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Bitcoin Mining Glossary

1443+ terms explained — from hashrate to halving

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Absolute Timelock

An absolute timelock prevents a Bitcoin transaction from being included in a block until a fixed point in the future…

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Absorption Chiller

An absorption chiller is a refrigeration machine that produces chilled water using a heat source rather than an electrically driven…

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Account (HD Wallet)

In a hierarchical deterministic wallet, an "account" is a distinct branch of the key tree that holds a self-contained set…

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Activation Function

An activation function is the nonlinear step applied to a neuron's weighted sum before it passes to the next layer.…

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Activation Recomputation

Activation recomputation, also called gradient or activation checkpointing, is a memory-saving technique that trades extra computation for reduced memory during…

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Activation Threshold

The activation threshold is the proportion of blocks that must signal support for a proposed soft fork before it locks…

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Adapter (LLM)

An adapter is a small, trainable neural module inserted between the layers of a large pretrained model to adapt it…

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Adapter Layer

An adapter layer is a small, trainable module inserted inside a frozen transformer so the model can be adapted to…

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Adaptor Signature

An adaptor signature is a cryptographic construction that ties the publication of a valid signature to the revelation of a…

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Address Manager (addrman)

The Address Manager, known in the Bitcoin Core source as addrman, is the in-memory database every full node uses to…

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Address Reuse

Address reuse means accepting multiple payments to — or spending and then reusing — the same Bitcoin address. Although it…

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addrv2 (BIP155)

BIP155 defines addrv2, a peer-to-peer message Bitcoin nodes use to share known peer addresses. It replaces the limitations of the…

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Adiabatic / Evaporative Cooling

Adiabatic, or evaporative, cooling uses the energy absorbed when liquid water turns to vapour to chill an air stream. Warm…

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Adjusted Cost Base (ACB)

Adjusted Cost Base (ACB) is the running cost, in Canadian dollars, of a property you hold — the figure the…

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Advantage Estimation

Advantage estimation is the process of computing how much better a particular action was than the model's average behavior in…

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Adversarial Example

An adversarial example is an input deliberately designed to make a machine learning model produce an incorrect output. As Goodfellow…

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Agent Memory

Agent memory is the set of mechanisms that let an LLM-driven agent hold onto information across turns, sessions, and tasks…

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Agent-to-Agent (A2A)

Agent-to-Agent, or A2A, is an open protocol that lets autonomous AI agents communicate and coordinate even when they were built…

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Agentic Workflow

An agentic workflow is an AI-driven process in which a language model does more than answer once: it plans, calls…

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AI Agent

An AI agent is a software system built around a large language model (LLM) that can pursue a goal autonomously:…

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AI Alignment

AI alignment is the broad research effort to ensure that an AI system's behavior and objectives match human values and…

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AI Watermarking

AI watermarking is the practice of embedding an imperceptible, machine-detectable signal directly into AI-generated text, images, audio, or video so…

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AIDA (Artificial Intelligence and Data Act)

The Artificial Intelligence and Data Act (AIDA) was Canada's first serious attempt at a national framework for regulating artificial intelligence.…

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Air Containment

Air containment is the set of physical barriers that seal a hot aisle / cold aisle layout so hot exhaust…

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Air Cooling

Beginner

Standard miner cooling using fans and heatsinks. Simple and effective but can be noisy for home use.

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Air-Gapped AI

Air-gapped AI means running language models or other AI systems on computers that are physically and logically isolated from any…

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Air-Gapped Signing

Air-gapped signing is the practice of signing Bitcoin transactions on a device that has no network connection of any kind,…

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Air-Side Economizer (Free Cooling)

An air-side economizer is the mechanism behind air-based free cooling. When outdoor air is cooler than the air leaving the…

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Altcoin

Altcoin is short for "alternative coin" and is a general label for any cryptocurrency other than Bitcoin. The term emerged…

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AML (Anti-Money Laundering)

Anti-Money Laundering (AML) refers to the framework of laws, regulations, and internal controls that financial institutions and crypto businesses must…

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AMTC (Antminer Maintenance Training Center)

AMTC — the Antminer Maintenance Training Center — is Bitmain's official training and certification program for ASIC miner repair, formerly…

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Analog-to-Digital Converter (ADC)

An analog-to-digital converter (ADC) translates a continuous analog voltage into a discrete digital number that a processor can act on.…

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Ancestor and Descendant Limits

Ancestor and descendant limits are mempool-policy caps on how many unconfirmed transactions may be linked together in a chain of…

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Anchor Connection

An anchor connection is a peer that a Bitcoin Core node deliberately tries to reconnect to immediately when it restarts.…

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Anchor Output

An anchor output is a small, immediately spendable output added to a Lightning Network commitment transaction so that either channel…

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Ancillary Services

Ancillary services are the support functions a grid operator relies on to keep electricity flowing reliably and to balance supply…

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Annular Ring

An annular ring is the band of copper that surrounds a drilled hole or via on a printed circuit board.…

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AnonCreds

AnonCreds (Anonymous Credentials) is an opinionated verifiable-credential format built from the ground up around zero-knowledge proofs, with the explicit goal…

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Anonymity Set

An anonymity set is the count of indistinguishable possibilities among which your activity is hidden. In a Bitcoin CoinJoin, if…

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Antenna Gain (dBi)

Antenna gain describes how effectively an antenna focuses transmitted (or received) radio energy in a particular direction rather than radiating…

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AntPool

AntPool is a Bitcoin mining pool launched in 2014 by Bitmain, the company behind the Antminer line of ASIC miners.…

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Any-to-Any Model

An any-to-any model is a multimodal system designed to both understand and generate across an arbitrary set of modalities within…

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Anycast

Anycast is an addressing and routing technique in which a single IP address is advertised from multiple physical locations at…

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AnyPrevOut (APO / BIP-118)

AnyPrevOut, abbreviated APO and specified in BIP-118, is a proposed new signature-hash (SIGHASH) mode for Bitcoin. A normal signature commits…

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Apache License 2.0

The Apache License 2.0 is a permissive open-source license maintained by the Apache Software Foundation. Like other permissive licenses it…

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Apartment Mining

Beginner

Mining in an apartment requires quiet hardware and low power. Open-source miners like Bitaxe are ideal.

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Approximate Nearest Neighbor (ANN)

Approximate Nearest Neighbor (ANN) search is the class of algorithms that powers fast similarity lookups in a vector database. Exact…

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APRS (Automatic Packet Reporting System)

APRS (Automatic Packet Reporting System) is an amateur-radio digital protocol for sharing real-time, location-aware data — GPS coordinates, weather telemetry,…

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Arc Flash

An arc flash is the dangerous release of energy that occurs when an electric arc bridges a gap between energized…

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AREDN (Amateur Radio Emergency Data Network)

AREDN (Amateur Radio Emergency Data Network) is open-source firmware, based on OpenWrt, that converts inexpensive commercial WiFi routers and radios…

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Arithmetic Intensity

Arithmetic intensity is the ratio of arithmetic work to data movement, usually expressed as floating-point operations per byte transferred (FLOPs/byte).…

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Ark

Ark is an off-chain protocol for fast, low-cost Bitcoin payments that avoids the inbound-liquidity and channel-management burdens of Lightning. It…

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Ark (Protocol)

Ark is an experimental Bitcoin layer-2 protocol designed for low-cost off-chain payments without the channel setup that Lightning requires. First…

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ASHRAE Thermal Guidelines

The ASHRAE Thermal Guidelines, published by ASHRAE Technical Committee 9.9, are the de facto reference for how warm and how…

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ASIC

Beginner

A specialized chip designed exclusively for Bitcoin mining, far faster and more efficient than general-purpose hardware.

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ASIC Chip

Intermediate

An individual mining chip that performs SHA-256 hashing. Modern miners contain dozens to hundreds of these.

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ASIC Resale Market

The ASIC resale market is the secondary market in which used and refurbished Bitcoin miners are bought and sold after…

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ASICBoost

ASICBoost is a proof-of-work optimization, invented by Timo Hanke and Sergio Demian Lerner in 2016, that exploits a structural quirk…

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Asset Issuance

Asset issuance is the process of creating a brand-new class of token on a Bitcoin sidechain such as Liquid. Any…

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Assume Valid (assumevalid)

Assume Valid, set with the -assumevalid option, is a Bitcoin Core feature that lets a node skip the most expensive…

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AssumeUTXO

AssumeUTXO is a Bitcoin Core feature that lets a new node become usable in minutes by loading a snapshot of…

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Atomic Multipath Payments (AMP)

Atomic Multipath Payments (AMP) extend the idea of splitting a Lightning payment across many routes, but add a cryptographic guarantee…

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Attack Surface

The attack surface is, in NIST's words, "the set of points on the boundary of a system, a system component,…

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Attention Sink

An attention sink is the empirical observation that the first few tokens of a sequence collect a disproportionately large share…

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Attenuation (RF)

Attenuation in radio is the reduction of signal power as a wave travels from transmitter to receiver. It accumulates from…

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AutoGen

AutoGen is an open-source programming framework for agentic AI, originally released by Microsoft Research. Its central idea is the conversable…

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Automatic Generation Control

Automatic Generation Control (AGC) is the centralized, closed-loop system that continuously adjusts the output of participating generators to keep system…

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Automatic Speech Recognition (ASR)

Automatic Speech Recognition (ASR) is the task of transcribing spoken language into written text. It is the technology behind dictation,…

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Automatic Transfer Switch (ATS)

An Automatic Transfer Switch (ATS) is a device that continuously monitors its primary power source and, the moment that source…

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Autotuning

Autotuning is a custom-firmware feature that finds the best operating point for a miner's ASIC chips instead of running them…

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AWQ (Activation-aware Weight Quantization)

AWQ (Activation-aware Weight Quantization) is a low-bit, weight-only quantization method for large language models, introduced by Lin et al. and…

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AxeOS

Beginner

Open-source firmware for Bitaxe miners. Web interface for pool setup, tuning, and monitoring.

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B

b-money

b-money is a 1998 proposal by computer engineer Wei Dai for an anonymous, distributed electronic cash system. Published in a…

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B.A.T.M.A.N. (Routing Protocol)

B.A.T.M.A.N. (Better Approach To Mobile Ad-hoc Networking) is a routing protocol for multi-hop wireless mesh networks, developed by the German…

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Backpropagation

Backpropagation is the algorithm that makes training a neural network possible. After the network makes a prediction and a loss…

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Bail-In

A bail-in is a method of resolving a failing bank by forcing its own creditors, rather than taxpayers, to absorb…

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Bank Run

A bank run occurs when a large number of depositors attempt to withdraw their funds at the same time, typically…

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Baseload

Baseload is the minimum, ever-present level of electricity demand on a grid, the "floor" of consumption that exists 24 hours…

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Baseload vs Peaking Power

Power plants are broadly classified by how often they run, measured as capacity factor, the share of energy actually produced…

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Batch Size (Inference)

Batch size in LLM inference is the number of requests or sequences the model processes together in a single forward…

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Battery Energy Storage System (BESS)

A Battery Energy Storage System (BESS) is a containerized bank of rechargeable cells—today almost always lithium iron phosphate (LFP)—paired with…

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Baud Rate

Baud rate is the signaling speed of a serial line, measured in symbols (for simple UART links, bits) per second.…

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BBS+ Signature

BBS+ is a multi-message signature scheme prized in decentralized identity because it delivers three strong privacy properties at once: selective…

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Beam Search

Beam search is a decoding algorithm that searches for a high-probability output sequence rather than sampling one token at a…

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Beam Width

Beam width is the central parameter of beam search, a decoding strategy used to generate text from a language model.…

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Bear Market

A bear market is a sustained period of falling asset prices accompanied by widespread pessimism and reduced confidence. A widely…

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Bearer Asset

A bearer asset is one whose ownership is determined entirely by possession of the asset (or the instrument that controls…

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Bech32

Bech32, specified in BIP173, is the address encoding introduced for native Segregated Witness. It replaced Base58Check for witness outputs and…

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Bech32m

Bech32m, specified in BIP350, is a small but important revision of the Bech32 address encoding. It is mandatory for Segregated…

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Behind-the-Meter

Behind-the-meter (BTM) describes electrical load that is wired directly to a generation source on the generator's side of the utility…

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Bench Power Supply

A bench power supply is an adjustable, regulated DC source used on a workbench to power a board under test.…

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Best-of-N Sampling

Best-of-N (BoN) sampling is an inference-time alignment method: instead of returning the first response a model produces, you sample N…

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BF16 (bfloat16)

BF16, or brain floating-point, is a 16-bit numeric format developed by the Google Brain team for training neural networks. It…

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BGA (Ball Grid Array)

BGA, or Ball Grid Array, is the surface-mount package format used for the hashing ASICs and many support chips on…

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BGP (Border Gateway Protocol)

Border Gateway Protocol (BGP) is the standardized exterior gateway protocol that lets independently operated networks, called autonomous systems (AS), tell…

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Bias-Variance Tradeoff

The bias-variance tradeoff is the central tension that governs how well a model generalizes. Bias is error from a model…

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Bill 96 (Quebec French-Language Law)

Bill 96 formally the Act respecting French, the official and common language of Québec is a 2022 statute that significantly…

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Binary Quantization (Embeddings)

Binary quantization compresses an embedding by reducing every float32 dimension to a single bit. The rule is trivial: if a…

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BIP Process (BIP 2)

The BIP process is the documented procedure by which changes to Bitcoin and its surrounding conventions are proposed, discussed, and…

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BIP21 (Bitcoin URI Scheme)

BIP21 defines the bitcoin: URI scheme, the format that lets a single scannable string carry not just an address but…

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BIP21 Payment URI

A BIP21 payment URI is a standardized bitcoin: link that lets a payer initiate a transaction by clicking a link…

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BIP32 (Hierarchical Deterministic Wallets)

BIP32 defines hierarchical deterministic (HD) wallets, the architecture behind nearly every modern Bitcoin wallet. Instead of generating and separately backing…

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BIP324 (v2 Encrypted P2P Transport)

BIP324 defines Bitcoin's version-2 (v2) peer-to-peer transport: an encrypted message layer that replaces the original plaintext v1 protocol used between…

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BIP44 Derivation Path

BIP44 is the Bitcoin Improvement Proposal that standardizes how hierarchical-deterministic (HD) wallets organize the billions of keys they can derive…

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BIP47 (Reusable Payment Codes / PayNym)

BIP47 defines reusable payment codes: a way to publish a single, permanent code that anyone can pay to without the…

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BIP70 (Payment Protocol)

BIP70 was an ambitious payment protocol designed to make Bitcoin payments to merchants safer and more informative than pasting a…

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BIP85 (Deterministic Entropy)

BIP85 is a Bitcoin Improvement Proposal that turns one master seed into a deterministic source of child entropy. From a…

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BIP9 / Version Bits

BIP9, commonly called version bits, is a mechanism for activating Bitcoin soft forks by treating the 32-bit block header version…

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Bit Gold

Bit Gold is a proposal by computer scientist and legal scholar Nick Szabo for a decentralized digital currency built on…

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Bitaxe

Beginner

An open-source solo Bitcoin miner. D-Central is a pioneer manufacturer with the original Mesh Stand.

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BitBox02

The BitBox02 is a hardware wallet developed and manufactured by Shift Crypto, a company based in Switzerland. It stores private…

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Bitcoin Core

Bitcoin Core is the reference implementation of the Bitcoin protocol and a direct descendant of the original client released by…

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Bitcoin Core Maintainer

A Bitcoin Core maintainer is a contributor trusted with commit access to the project's repository. The role is deliberately narrow:…

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Bitcoin Core Release Process

The Bitcoin Core release process is the documented sequence of steps that turns the project's source tree into versioned, verifiable…

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Bitcoin Developer Mailing List

The Bitcoin developer mailing list is the long-standing public forum where technical proposals, protocol changes, and Bitcoin Improvement Proposals are…

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Bitcoin Faucet

A Bitcoin faucet is a service that hands out small amounts of coins for free. On test networks, faucets are…

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Bitcoin Knots

Bitcoin Knots is a Bitcoin full-node and wallet implementation derived from the Bitcoin Core codebase. Maintained primarily by Luke Dashjr,…

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Bitcoin Pizza Day

Bitcoin Pizza Day is observed each May 22 to commemorate what is widely cited as Bitcoin's first real-world commercial transaction.…

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Bitcoin Script

Bitcoin Script is the small, stack-based programming language that Bitcoin uses to express the conditions for spending coins. It resembles…

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Bitcoin Vault

A Bitcoin vault is a custody construction that adds a mandatory delay and a recovery path to the spending of…

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Bitcoin Vault (Concept)

A Bitcoin vault is a self-custody design that places a mandatory delay and a recovery path between an attempt to…

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Bitcoin Whitepaper

The Bitcoin Whitepaper, formally titled Bitcoin: A Peer-to-Peer Electronic Cash System, is the founding document of the network. The pseudonymous…

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Bits

Advanced

A compact encoding of the mining difficulty target stored in each block header.

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bitsandbytes

bitsandbytes is an open-source library that adds low-precision quantization to PyTorch models with minimal code changes. It is best known…

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BitVM

BitVM is a paradigm for expressing arbitrary, Turing-complete computation that can be verified on Bitcoin without changing Bitcoin's consensus rules.…

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BitVM2

BitVM2 is a verification scheme that enables arbitrary, effectively Turing-complete computation to be secured by Bitcoin, presented by Robin Linus…

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Black Start

A black start is the process of restoring a power system from a complete shutdown without relying on the external…

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Blame Round

A blame round is the recovery mechanism a CoinJoin protocol triggers when a transaction fails to finalize because one or…

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BLEU and ROUGE

BLEU and ROUGE are two foundational automatic metrics for evaluating generated text against human reference text by counting overlapping word…

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Blinded Signature

A blinded (or blind) signature is a cryptographic construction, introduced by David Chaum in 1982, in which a signer authenticates…

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Block

Beginner

A bundle of Bitcoin transactions added to the blockchain. Miners compete to create each new block.

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Block Explorer

A block explorer is a web-based tool that indexes a blockchain and lets anyone search and inspect its contents: individual…

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Block Filter Index

The block filter index is an optional Bitcoin Core database, enabled with -blockfilterindex=basic, that precomputes a compact filter for every…

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Block Find Probability

Intermediate

The odds of your miner finding a block based on your share of network hashrate. Low for small miners but…

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Block Header

Intermediate

The 80-byte section of a block that miners hash. Contains version, previous hash, Merkle root, time, target, and nonce.

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Block Height

Beginner

The position number of a block in the blockchain, starting from zero at the genesis block.

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Block Propagation

Block propagation is the process of relaying a newly mined block across Bitcoin's peer-to-peer network so that every node receives,…

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Block Reorganization (Reorg)

A block reorganization, or reorg, happens when a node abandons one or more blocks at the tip of its chain…

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Block Reward

Beginner

The Bitcoin earned by mining a block. Currently 3.125 BTC, it halves roughly every four years.

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Block Size War

The Block Size War was a prolonged governance conflict, roughly 2015 to 2017, over how Bitcoin should scale to handle…

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Block Subsidy

Beginner

The newly created Bitcoin in each block, currently 3.125 BTC. Halves every four years until supply reaches 21M.

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Block Subsidy Reduction Hedge (Halving Hedge)

A block subsidy reduction hedge, often called a halving hedge, is the use of mining derivatives to fix revenue ahead…

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Block Template

Advanced

A candidate block that miners hash. Contains selected transactions and metadata ready for mining.

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Block Template Construction

Block template construction is the process of assembling a candidate block for miners to work on: choosing which transactions to…

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Block Time

Beginner

The average time between blocks, targeted at 10 minutes. Individual blocks vary randomly around this average.

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Block Withholding Attack

A block withholding attack targets a mining pool from the inside. The attacker joins the pool and mines normally, submitting…

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Block-Relay-Only Connection

A block-relay-only connection is a special type of outbound link that a Bitcoin Core node opens to a peer for…

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Blockstream Jade

Blockstream Jade is a hardware wallet produced by Blockstream for securing Bitcoin and Liquid assets. It signs transactions on-device and…

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Bloom Filter (BIP37)

BIP37 introduced connection Bloom filtering, the first widely deployed way for a Simplified Payment Verification (SPV) wallet to download only…

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Blossom (Media Storage)

Blossom is a protocol for storing binary media, called blobs, on servers that are independent of Nostr relays. It exists…

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BLS Signature

A BLS signature is a digital signature scheme built on bilinear pairings over a pairing-friendly elliptic curve, named after its…

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BM1366

Intermediate

A Bitmain mining chip powering the Antminer S19 XP and Bitaxe Supra. Efficient at around 21.5 J/TH.

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BM1368

Intermediate

A Bitmain chip used in Antminer S21 variants and the Bitaxe Gamma open-source miner.

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BM1370

Intermediate

Bitmain's latest mining chip in the Antminer S21. Industry-leading efficiency at approximately 15 J/TH.

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BOLT Specification

BOLT stands for Basis of Lightning Technology, the set of open specifications that define how Lightning Network implementations interoperate. Maintained…

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BOLT12 (Offers)

BOLT12, commonly called "Offers," is a Lightning Network payment protocol that introduces a reusable, static payment code in place of…

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BRC-20

BRC-20 is an experimental fungible-token standard built on top of Bitcoin Ordinals. Created in March 2023 by a pseudonymous developer…

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Break-Even

Beginner

The electricity rate where mining revenue equals power costs. Below this rate, mining is profitable.

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Break-even Electricity Price

The break-even electricity price is the maximum rate, expressed in dollars per kilowatt-hour, that a miner can pay for power…

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Briar

Briar is an open-source, censorship-resistant messaging app that works without any central server. Messages are synchronized directly between users' devices…

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Bribery Attack

A bribery attack subverts proof-of-work consensus not by owning a hashrate majority but by renting one. The attacker offers miners…

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Bricking (ASIC Miner)

Bricking is the slang term for an ASIC miner that will no longer boot or respond after its firmware has…

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Broadband-Hamnet (HSMM-Mesh)

Broadband-Hamnet, originally called HSMM-Mesh (High-Speed Multimedia Mesh), is a system that lets licensed amateur-radio operators run high-speed TCP/IP data networks…

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BTCPay Server

BTCPay Server is a free and open-source, self-hosted Bitcoin payment processor that lets a merchant accept Bitcoin payments directly, without…

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BTU Output

Beginner

Heat output in BTU/hr, calculated as watts times 3.412. Helps compare miners to traditional heaters.

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Buck Converter

A buck converter is a DC-DC switching regulator that steps a higher voltage down to a lower one. On an…

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Bull Market

A bull market is a sustained period of rising asset prices accompanied by broad optimism among participants. A common rule…

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Bulletproof

A Bulletproof is a short, non-interactive zero-knowledge argument of knowledge that requires no trusted setup. Introduced by Bunz, Bootle, Boneh,…

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Burn-In

Burn-in is a reliability screening process in which a freshly manufactured chip is deliberately operated at elevated voltage and temperature…

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Busbar

A busbar is a rigid metallic conductor—typically copper, sometimes aluminum—used to collect and distribute large electrical currents to many branch…

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Busway (Busduct)

A busway, sometimes called busduct, is a prefabricated modular power-distribution system in which solid copper or aluminum conductors (busbars) are…

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Byte-Pair Encoding (BPE)

Byte-Pair Encoding (BPE) is the subword tokenization algorithm that underpins most modern large language models, including the GPT family. Originally…

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Byzantine Fault Tolerance

Byzantine Fault Tolerance (BFT) is the property that lets a distributed system reach correct agreement even when some of its…

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C

Canary Deployment

Canary deployment is a progressive rollout strategy for safely shipping a new model version into production. Instead of switching every…

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Cantillon Effect

The Cantillon effect describes how newly created money does not raise all prices at the same time, so the order…

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Capacitor

A capacitor stores electrical energy as charge on two conductive plates separated by an insulating dielectric. It opposes changes in…

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Capacitor Plague

The capacitor plague refers to an era (roughly 1999 to 2007) when large numbers of aluminum electrolytic capacitors failed prematurely…

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Capacity Factor

Capacity factor is the ratio of a power source's actual energy output over a period to the output it would…

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Capacity Market

A capacity market is a mechanism used in some grid regions to ensure resource adequacy — the long-term ability of…

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Capital Controls

Capital controls are policy measures a government or central bank uses to limit the flow of money into or out…

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Capital Gains (Crypto, Canada)

A capital gain arises when you dispose of a cryptocurrency held as an investment for more than its adjusted cost…

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Cashu

Cashu is a free and open-source Chaumian ecash protocol for Bitcoin. A user pays a Lightning invoice to a "mint,"…

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Catastrophic Forgetting

Catastrophic forgetting, also called catastrophic interference, is the tendency of a neural network to lose previously learned knowledge when it…

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CC0 / Public Domain Dedication

CC0 1.0 is a legal tool from Creative Commons that lets a creator dedicate a work to the public domain…

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Censorship Resistance

Censorship resistance is a network's ability to process valid transactions regardless of their origin, destination, or purpose, with no party…

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CERN-OHL (CERN Open Hardware Licence)

The CERN Open Hardware Licence (CERN-OHL) is a legal tool developed by CERN to promote collaboration among hardware designers and…

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CFM (Airflow)

CFM (cubic feet per minute) is the volume of air moved per minute by a fan, blower, or whole cooling…

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Chain Analysis

Chain analysis is the discipline — and the industry — of mining Bitcoin's public, permanent ledger to link addresses, build…

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Chain Reorganization (Reorg)

A chain reorganization, or reorg, happens when a node drops blocks it had previously accepted at the tip and switches…

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Chain Split

A chain split occurs when the Bitcoin network diverges into two competing blockchains that share a common history up to…

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Chain-of-Thought Decoding

Chain-of-Thought decoding is a method for drawing reasoning out of a pre-trained language model by changing how it decodes rather…

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Chain-of-Thought Prompting

Chain-of-thought (CoT) prompting is a technique that improves a language model's reasoning by encouraging it to generate intermediate steps before…

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Change Address

A change address is where a Bitcoin wallet returns the surplus when the UTXOs it spends are worth more than…

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Change Output

Because Bitcoin spends whole Unspent Transaction Outputs (UTXOs), a wallet rarely has a coin that matches the exact payment amount.…

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Channel (Meshtastic)

A channel in Meshtastic is a named, encrypted logical group that determines which nodes can read and relay a given…

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Channel Capacity

Channel capacity is the total amount of Bitcoin committed to a Lightning payment channel between two nodes. It is fixed…

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Channel Factory

A channel factory is a multi-party Lightning construction in which a group of users cooperatively lock their funds into a…

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Chat Template

A chat template is the formatting specification that turns a structured list of messages — each tagged with a role…

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Chatbot Arena (Elo Rating)

Chatbot Arena is an open evaluation platform launched in 2023 by LMSYS and UC Berkeley's SkyLab that ranks language models…

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Chaumian Mint (ecash)

A Chaumian mint is a service that issues digital bearer tokens, ecash, using blind signatures, a technique David Chaum described…

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Child-Pays-For-Parent (CPFP)

Child-Pays-For-Parent, or CPFP, is a fee-bumping technique that lets the receiver of funds, not just the sender, speed up a…

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Chinchilla-Optimal Training

Chinchilla-optimal training refers to the compute-optimal recipe established by DeepMind's 2022 study "Training Compute-Optimal Large Language Models." Its central finding:…

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Chip Binning

Chip binning is the manufacturing practice of testing each ASIC die and sorting it into performance "bins" — grades defined…

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Chip Domain Bypass

Chip domain bypass is a salvage technique that electrically jumpers out a failed voltage domain so the remaining domains on…

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Chip Package

A chip package is the protective enclosure built around a bare semiconductor die that does three jobs at once: it…

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Chip Select

Chip select (often written CS, or SS for slave select) is a control line that tells a single chip on…

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Chiplet

A chiplet is a discrete, unpackaged die that implements one functional block, such as compute cores, memory, or I/O, and…

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Chunked Prefill

Chunked prefill is a scheduling optimization used when serving large language models on a GPU. Inference has two phases with…

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Chunking

Chunking is the step in a retrieval pipeline where long documents are split into smaller passages before they are embedded…

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Circuit Breaker

A circuit breaker is an electromechanical switch that automatically opens a circuit when it detects an overcurrent, short circuit, or…

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cjdns

cjdns implements an encrypted IPv6 network using public-key cryptography for address allocation and a distributed hash table (DHT) for routing.…

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Class 50 CCA (Computer Hardware)

Capital Cost Allowance (CCA) is how Canadian businesses deduct the cost of depreciable assets over time instead of all at…

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Client-Side Validation

Client-side validation is the design principle behind RGB and similar Bitcoin smart-contract systems, in which the full state and history…

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CLIP (Contrastive Language-Image Pre-training)

CLIP (Contrastive Language-Image Pre-training) is a multimodal model released by OpenAI in 2021 that learns to associate images with natural-language…

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Clock Domain Crossing (CDC)

A clock domain is a region of a chip driven by a single clock. A clock domain crossing (CDC) happens…

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Clock Gating

Clock gating is a low-power design technique that disables the clock signal to a circuit block whenever that block has…

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Clock Tree

A clock tree is the network of wires and buffers that distributes a single clock signal from its source to…

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CLOUD Act

The CLOUD Act (Clarifying Lawful Overseas Use of Data Act, 18 U.S.C. § 2713, signed into law March 23, 2018)…

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Cloud Mining

Cloud mining is an arrangement in which a customer pays a provider for a share of remote mining capacity rather…

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Cluster Mempool

Cluster mempool is a major reworking of how Bitcoin Core organises unconfirmed transactions. Instead of tracking loose ancestor and descendant…

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Code Review Culture (Bitcoin Core)

Code review culture describes the norms that govern how changes enter Bitcoin Core. The project treats careful, independent review as…

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Coin Control

Coin control is a wallet feature that lets you manually select which specific unspent transaction outputs (UTXOs) a transaction will…

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Coin Days Destroyed

Coin Days Destroyed (CDD) is an on-chain metric that weights the movement of coins by how long they sat unspent.…

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Coinbase Commitment

A coinbase commitment is the general technique of placing a cryptographic hash or marker inside a block's coinbase transaction so…

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Coinbase Maturity

Coinbase maturity is the Bitcoin consensus rule that newly mined coins cannot be spent immediately. The output of a coinbase…

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Coinbase Transaction

Intermediate

The special first transaction in each block that creates new Bitcoin and pays the miner.

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CoinJoin

CoinJoin is a privacy technique, first proposed by Bitcoin Core contributor Gregory Maxwell in 2013, in which several independent participants…

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CoinJoin Coordinator

A CoinJoin coordinator is the service that orchestrates a collaborative transaction between many Bitcoin users, collecting each participant's registered inputs…

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Coinstats Index

The coinstats index, enabled with -coinstatsindex=1, is an optional Bitcoin Core database that precomputes statistics about the unspent transaction output…

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CoinSwap

CoinSwap is an on-chain privacy protocol, first sketched by Greg Maxwell in 2013 and later developed as the Maxwell-Belcher protocol,…

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Cold Boot Attack

A cold boot attack recovers the contents of a computer's volatile memory, RAM, shortly after power is removed, exploiting a…

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Cold Joint

A cold solder joint is a defective connection that forms when the solder fails to reach a high enough temperature…

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Cold Plate

A cold plate, also called a water block, is a sealed metal block, usually copper or aluminum, with internal channels…

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Cold Storage

Cold storage is any method of holding Bitcoin private keys on a device that is kept offline. The defining property…

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Coldcard

Coldcard is a Bitcoin-only hardware signing device manufactured by Coinkite, a company based in Toronto, Canada. It is designed to…

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Colocation (Mining)

Colocation in Bitcoin mining is an arrangement where you retain ownership of your ASIC hardware but ship it to a…

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Combined Cycle

A combined cycle is a power-generation arrangement that captures the hot exhaust of a gas (combustion) turbine and uses it…

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Combined Cycle Gas Turbine (CCGT)

A Combined Cycle Gas Turbine (CCGT) plant captures the waste heat from a gas turbine's exhaust to raise steam for…

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Combined Heat and Power (CHP)

Combined heat and power (CHP), also called cogeneration, is the simultaneous production of electricity and useful heat from a single…

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Commitment Scheme

A commitment scheme is a fundamental cryptographic primitive that works like a sealed, tamper-evident envelope: a party can commit to…

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Common-Input-Ownership Heuristic

The Common-Input-Ownership Heuristic (CIOH) is the single most important assumption in Bitcoin blockchain analysis. It holds that whenever a transaction…

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Compact Block

A compact block is a bandwidth-efficient way of relaying a newly mined block, defined in BIP152 and active in Bitcoin…

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Compact Block Filters (BIP157/158)

Compact Block Filters let a lightweight Bitcoin wallet decide which blocks contain transactions it cares about without telling any peer…

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Compact Block Relay (BIP152)

Compact Block Relay, specified in BIP152, reduces the bandwidth and latency of propagating a newly mined block across the Bitcoin…

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Compact Blocks (BIP-152)

Compact Blocks, specified in BIP-152 and merged into Bitcoin Core in June 2016, is a peer-to-peer relay optimization that dramatically…

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Compartmentalization

Compartmentalization is the practice of dividing sensitive information, activities, and access into discrete, isolated cells, where each cell holds only…

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Compute Sovereignty

Compute Sovereignty is the principle and practice of running your computations on hardware you own or directly control, without dependency…

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Compute-Bound vs Memory-Bound

Every workload running on an accelerator is limited by one of two resources at any moment: the speed of its…

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Confidential Assets

Confidential Assets is the cryptographic feature that lets a Bitcoin sidechain hide which asset is moving in a transaction, not…

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Config Backup (Miner Settings)

A config backup is a saved copy of an ASIC miner's working settings: its pool URLs and worker credentials, network…

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Confirmation

A confirmation is a block that includes your transaction (or is mined on top of the block that does). The…

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Confirmation Time

Confirmation time is the interval between broadcasting a Bitcoin transaction and a miner including it in a block, giving it…

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Confirmations

Beginner

The number of blocks mined after a transaction, indicating how secure and irreversible it is.

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Confirmations Depth

Confirmations depth is the count of blocks built on top of the block that contains a given transaction, including that…

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Conformal Coating

Conformal coating is a thin protective film applied over a fully assembled printed circuit board to shield it from moisture,…

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Congestion Control Tree

A congestion control tree is a proposed transaction structure, enabled by a template-commitment opcode such as OP_CHECKTEMPLATEVERIFY, that lets a…

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Constitutional AI

Constitutional AI (CAI) is an alignment approach published by Anthropic in 2022 that trains a model to be harmless using…

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Constrained Decoding

Constrained decoding, also called guided or structured decoding, is a method that guarantees a language model's output conforms to a…

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Contactor

A contactor is a specialized relay designed to switch high-power loads on and off repeatedly under remote control. An energized…

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Context Compression

Context compression packs a long input into a much smaller set of learned representations, often called memory slots or soft…

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Context Window

The context window is the maximum amount of tokenized text a large language model can consider at one time. It…

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Continuity Test

A continuity test is a basic but essential diagnostic that checks whether an unbroken electrical path exists between two points.…

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Continuous Batching

Continuous batching is a scheduling technique for serving large language models that dramatically improves how many requests a GPU can…

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Contract Execution Transaction (CET)

A Contract Execution Transaction (CET) is one of a set of pre-signed Bitcoin transactions created when two parties open a…

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Contrastive Learning

Contrastive learning is a representation-learning technique that teaches a model to produce useful vectors by comparison: it pulls positive pairs…

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Control Block (Taproot)

The control block is the witness element that makes a Taproot script-path spend verifiable. When a spender reveals a script…

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Control Board

Intermediate

The management board in an ASIC miner that runs firmware, coordinates hashboards, and connects to the network.

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Controlled Impedance

Controlled impedance is the practice of designing a PCB trace so its characteristic impedance stays within a specified tolerance of…

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ControlNet

ControlNet is a neural network architecture, introduced by Lvmin Zhang and collaborators in 2023, that adds precise spatial control to…

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Convolutional Neural Network (CNN)

A Convolutional Neural Network (CNN) is a class of deep neural network that uses convolutional layers to filter inputs for…

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Coolant Distribution Unit (CDU)

A Coolant Distribution Unit (CDU) is the central pump-and-heat-exchanger module at the heart of a liquid cooling system. It circulates…

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Coolant Distribution Unit (CDU)

A Coolant Distribution Unit (CDU) is the bridge between a facility's cooling plant and the liquid-cooled hardware it serves. It…

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Cooling Tower

A cooling tower is a heat-rejection device that dumps a facility's waste heat into the atmosphere. Where a heat exchanger…

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Copper Pour

A copper pour is a large filled region of copper on a printed circuit board layer, as opposed to a…

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Copper Weight

Copper weight specifies how thick the copper foil on a PCB layer is, expressed in ounces per square foot (oz/ft2).…

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Copyleft

Copyleft is a general method for making a program or other work free and requiring that all modified and extended…

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Core Lightning (CLN)

Core Lightning (CLN), formerly known as c-lightning, is an implementation of a full Lightning Network node maintained by Blockstream under…

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Cosine Similarity

Cosine similarity measures how alike two vectors are by computing the cosine of the angle between them. The result ranges…

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Counterparty Risk

Counterparty risk is the chance that the party on the other side of a financial obligation cannot or will not…

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Covenant

A covenant is a restriction encoded into a Bitcoin output that limits how the coins can be spent in the…

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Covenant (Bitcoin)

A covenant is a spending condition that constrains how bitcoin may be spent in the future, rather than only who…

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Cover Traffic

Cover traffic is the practice of sending dummy messages that carry no real payload, purely to obscure the timing and…

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CRA Crypto Guidance

The Canada Revenue Agency (CRA) publishes guidance on how it taxes cryptocurrency, and it is the starting point for any…

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Creep Corrosion

Creep corrosion is a failure mode in which a corrosion product, most commonly copper sulfide, forms on exposed metal and…

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Crest Factor

Crest factor is the ratio of the peak value of a waveform to its RMS (root-mean-square) value. For a perfect…

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CrewAI

CrewAI is an open-source framework, written primarily in Python and released under the MIT license, for orchestrating role-playing, autonomous AI…

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Cross-Attention Fusion

Cross-attention fusion is a way of feeding one modality (typically vision) into a language model by inserting attention layers whose…

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Cross-Input Signature Aggregation (CISA)

Cross-Input Signature Aggregation (CISA) is a proposed Bitcoin protocol upgrade that would let a transaction combine the separate signatures from…

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Crypto-Anarchy

Crypto-anarchy is a strand of political thought, articulated by Timothy C. May in his 1988 Crypto Anarchist Manifesto, holding that…

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Cryptographic Accumulator

A cryptographic accumulator is a primitive that compresses an arbitrarily large set of elements into a single short digest, while…

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Crystal Oscillator

A crystal oscillator is an electronic circuit that uses a precisely cut piece of piezoelectric quartz to generate a stable,…

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CUDA

CUDA (Compute Unified Device Architecture) is NVIDIA's parallel-computing platform and programming model. It gives developers direct, general-purpose access to NVIDIA…

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Currency Debasement

Currency debasement is the reduction of a currency's intrinsic or real value by its issuer. In the era of metallic…

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Curriculum Learning

Curriculum learning is a training strategy that feeds a model examples in a deliberately chosen order, typically from easy to…

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Curtailable Load

A curtailable load is an electricity consumer that can rapidly reduce or shut off its power draw when asked —…

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Curtailment

Curtailment is the deliberate reduction of electricity production or consumption. On the supply side, a wind or solar farm is…

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Custom Firmware

Intermediate

Third-party firmware replacing stock software for better efficiency, autotuning, and monitoring features.

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Cypherpunk

A cypherpunk is an activist who uses strong cryptography and free software as the primary tools for defending personal privacy…

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D

Dandelion (BIP156)

Dandelion, specified in BIP156, is a proposed transaction-relay routing technique that makes it harder for a network observer to identify…

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Data Augmentation

Data augmentation is the practice of artificially enlarging a training dataset by creating modified copies of the data you already…

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Data Broker

A data broker is a business whose product is you. Brokers collect personal information from public records, app SDKs, loyalty…

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Data Lake

A data lake is a centralized, highly scalable repository that stores vast volumes of raw data — structured, semi-structured, and…

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Data Localization

Data localization is a legal requirement that data must be stored — and sometimes processed — within a specific country's…

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Data Parallelism

Data parallelism is the most common way to train a neural network across multiple accelerators. Every device holds a complete…

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Data Pipeline / ETL

A data pipeline is an automated workflow that moves data from where it is produced to where it is consumed,…

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Data Poisoning

Data poisoning is an attack in which an adversary controls part of the data used to train a machine-learning model,…

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Data Residency

Data residency refers to the physical or geographic location where your data is stored and processed and, by extension, which…

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Data Sovereignty

Data Sovereignty is the principle that data is subject to the laws and governance frameworks of the jurisdiction in which…

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Data Vending Machine (DVM)

A Data Vending Machine is an on-demand computation marketplace defined by NIP-90. The spec sums it up as "money in,…

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DATUM

DATUM (Decentralized Alternative Templates for Universal Mining) is a mining protocol developed by the OCEAN pool that lets individual miners…

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dbcache

dbcache is the Bitcoin Core option, set with -dbcache=<n> in MiB, that controls how much memory the node devotes to…

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dBm

dBm, short for decibel-milliwatts, is a logarithmic unit expressing absolute radio power referenced to one milliwatt. It is the default…

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Dead Man’s Switch

A dead man's switch is a mechanism that automatically performs a predetermined action when the operator fails to provide a…

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Debasement

Debasement is the deliberate reduction of the intrinsic value of a currency while its nominal face value is held constant.…

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Debian

Debian is a universal, free operating system produced by the Debian Project, an association of around a thousand volunteer developers…

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Decentralized Computing

Decentralized Computing is the distribution of computational workloads across many independently owned and operated nodes, such that no single entity…

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Decentralized Identifier (DID)

A Decentralized Identifier (DID) is a new class of identifier that lets a person, organization, or device prove control of…

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Decode Phase

The decode phase is the second stage of large language model (LLM) inference, following prefill. Here the model produces output…

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Decoding Strategy

A decoding strategy is the algorithm that converts a language model's raw per-step probability distribution into a concrete sequence of…

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Deep Packet Inspection (DPI)

Deep packet inspection (DPI) is a form of network analysis that examines not just a packet's routing headers but the…

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Deepfake

A deepfake is synthetic media — video, audio, or imagery — generated or manipulated by AI to convincingly portray a…

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Defect Density

Defect density, usually written D0, is the average number of killer defects per unit area of a wafer, expressed in…

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Defense in Depth

Defense in depth is the principle that security should never rest on a single control. Instead you stack multiple independent…

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Deflation

Deflation is a sustained decline in the general price level of goods and services across an economy, the opposite of…

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Delta-T (Thermal)

Delta-T (written ΔT) is the temperature difference between two points in a thermal system, calculated by subtracting one temperature from…

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Demand Charge

A demand charge is a component of a commercial or industrial electricity bill based not on how much energy you…

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Demand Response

Demand response is a grid-management practice in which large electricity consumers reduce or shift their power usage in response to…

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Dendrite Growth

Dendrite growth is the formation of branching, tree-like metallic deposits that bridge between conductors on a circuit board. Unlike tin…

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Deniable Authentication

Deniable authentication is a cryptographic property that lets a recipient be confident who sent a message during a conversation, while…

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Dennard Scaling

Dennard scaling is the scaling law, formulated in a 1974 paper led by IBM's Robert Dennard, stating that as transistors…

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Dense vs Sparse Retrieval

Dense and sparse retrieval are the two foundational ways to match a query against a document corpus, and understanding the…

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Descriptor Wallet

A descriptor wallet is defined by one or more output script descriptors rather than by a bare set of keys.…

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Desoldering Braid

Desoldering braid, also called solder wick, is a fine woven copper braid coated in flux that is used to remove…

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Deterministic Nonce (RFC 6979)

A deterministic nonce, specified in RFC 6979, is a way of generating the secret per-signature value k used in ECDSA…

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Diagnostic

Intermediate

Identifying faults in mining hardware using test equipment and systematic testing before repair.

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DID Document

A DID Document is the payload you get when you resolve a decentralized identifier. It is the serialization of the…

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DID Method

A DID Method is the ruleset that makes a particular family of decentralized identifiers actually work. Every DID carries a…

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did:web

The did:web method is the most pragmatic on-ramp to decentralized identity: it ties a DID Document to a web domain…

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Dielectric Coolant Types

Dielectric coolants are electrically non-conductive liquids that can touch live electronics directly while carrying heat away. Several distinct chemistry families…

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Dielectric Fluid

A dielectric fluid is a coolant that does not conduct electricity, which is precisely what lets you submerge live electronics…

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Differential Pair

A differential pair is two PCB traces routed side by side, carrying signals of equal magnitude and opposite polarity. The…

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Difficulty

Beginner

A value that controls how hard it is to mine a Bitcoin block, adjusted every two weeks to maintain 10-minute…

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Difficulty Adjustment

Beginner

The automatic recalculation of mining difficulty every 2,016 blocks to maintain 10-minute block times.

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Difficulty Manipulation

Difficulty manipulation refers to attacks that distort Bitcoin's difficulty adjustment by exploiting how the protocol uses block timestamps. Every 2,016…

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Difficulty Ribbon

The Difficulty Ribbon is an on-chain indicator that visualizes the rate of change in Bitcoin's mining difficulty. Created by analyst…

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Diffusion Model

A diffusion model is a class of generative AI that produces images (and increasingly audio and video) by learning to…

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Digital Sovereignty

Digital Sovereignty is the capacity of an individual, organization, or jurisdiction to own and control its digital infrastructure — including…

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Diode

A diode is a two-terminal semiconductor component that allows current to flow easily in one direction (forward bias) while blocking…

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Dipole Antenna

A dipole is the most fundamental practical antenna: a straight conductor, classically a half-wavelength long, fed at its centre so…

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Direct Preference Optimization (DPO)

Direct Preference Optimization (DPO) is a technique for aligning a language model with human preferences without training a separate reward…

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Discrete Logarithm Problem

The discrete logarithm problem (DLP) is the mathematical hardness assumption that secures every Bitcoin key. In its elliptic-curve form (ECDLP),…

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Distributed Compute

Distributed Compute is the practice of splitting computational tasks — model inference, data processing, simulation, or hash computation — across…

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District Heating

District heating is a system that distributes thermal energy from one or more central sources to many buildings through a…

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DMZ (Network)

In networking, a DMZ (demilitarized zone), also called a perimeter network or screened subnet, is an isolated subnet that sits…

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DNS (Domain Name System)

The Domain Name System (DNS) is a hierarchical, distributed naming service that translates human-readable domain names like example.com into the…

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Dollar Cost Averaging Mining

Beginner

Continuously mining to accumulate Bitcoin steadily over time, regardless of price movements.

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Dollar-Cost Averaging (DCA)

Dollar-cost averaging (DCA) is the practice of investing a fixed amount of money at regular intervals weekly, monthly, or quarterly…

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Domain Fronting

Domain fronting is a circumvention technique that hides the true destination of an HTTPS request by presenting one (typically permitted)…

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DoRA (Weight-Decomposed Low-Rank Adaptation)

DoRA (Weight-Decomposed Low-Rank Adaptation) is a parameter-efficient fine-tuning method that improves on LoRA by first decomposing each pre-trained weight matrix…

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Double Ratchet Algorithm

The Double Ratchet Algorithm is the engine that gives modern secure messengers their per-message key freshness. After two parties establish…

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Double SHA-256

Advanced

Applying SHA-256 twice in sequence, the specific hashing method Bitcoin uses for block mining.

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Double Spend

A double spend is the act of successfully spending the same coins more than once. It is the central problem…

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DPO (Direct Preference Optimization)

Direct Preference Optimization (DPO) is a 2023 method from Rafailov and colleagues at Stanford that aligns language models to human…

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Drift Detection

Drift detection is the practice of spotting when a deployed model's world has changed enough to hurt its accuracy. Models…

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Drivechain

Drivechain is a proposed mechanism, authored by Paul Sztorc as BIP-300 and BIP-301, that would let Bitcoin support sidechains with…

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Droop Control

Droop control is a simple, decentralized method that lets multiple power sources run in parallel and share load without communicating.…

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Dry Joint

A dry joint is a soldered connection that never properly bonded to the metal surfaces it joins, usually because too…

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Dry-Type Transformer

A dry-type transformer uses air, and often cast-resin or varnish-impregnated solid insulation, as its cooling and insulating medium instead of…

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Dual-Purpose Mining

Beginner

Mining Bitcoin while using the heat productively for heating spaces, water, or other applications.

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Duct Adapter

Beginner

A connector between a miner's exhaust and standard HVAC ducting for directing hot air where needed.

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Duress Wallet

A duress wallet is a decoy cryptocurrency wallet designed to be surrendered if you are physically coerced into unlocking your…

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Dust Attack

A dust attack (or dusting attack) is a privacy assault in which an adversary sprays minuscule amounts of Bitcoin —…

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Dust Limit

The dust limit is a Bitcoin Core relay-policy threshold that rejects transaction outputs whose value is too low to be…

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Dynamic DNS (DDNS)

Dynamic DNS (DDNS) is a service that automatically updates a domain name's DNS record whenever the underlying IP address changes.…

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Dynamic Voltage and Frequency Scaling (DVFS)

Dynamic voltage and frequency scaling (DVFS) is the practice of adjusting a chip's supply voltage and clock frequency together to…

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E

E-Fuse

An e-fuse (electrically programmable fuse, or eFuse) is a tiny one-time-programmable element built directly into a silicon die. A narrow…

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EAGLE Decoding

EAGLE (Extrapolation Algorithm for Greater Language-model Efficiency) is a speculative-decoding technique that speeds up large language model inference without changing…

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Early vs Late Fusion

Early fusion and late fusion describe where in a pipeline information from different modalities gets combined. The choice shapes how…

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Ecash

Ecash (electronic cash) is a class of bearer-token money in which value is represented by cryptographic tokens that can be…

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Eclair

Eclair is an implementation of a full Lightning Network node, written in Scala and maintained by ACINQ. It runs on…

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Eclipse Attack

An eclipse attack lets an adversary who controls enough IP addresses monopolize every connection to and from a victim Bitcoin…

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Eclipse-Attack Resistance

Eclipse-attack resistance is the collection of design choices in Bitcoin Core that make it hard for an attacker to eclipse…

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Economizer

An economizer is a heat exchanger that recovers waste heat from a boiler's flue gases and uses it to preheat…

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Edge Connector

An edge connector is the row of flat metal contacts along the edge of a printed circuit board that plugs…

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EEPROM (Hashboard)

An EEPROM (Electrically Erasable Programmable Read-Only Memory) is the small non-volatile memory chip found on each Antminer hashboard that stores…

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Efficiency (J/TH)

Beginner

Energy efficiency of a miner in Joules per Terahash. Lower is better as it means less electricity per unit of…

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Electrical Substation

An electrical substation is a node in the power grid that transforms voltage between levels and routes, controls, and protects…

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Electricity Cost

Beginner

The cost of power for mining, measured in $/kWh. The biggest ongoing expense, varying greatly by location.

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Electromigration

Electromigration is the gradual mass transport of metal atoms within a conductor, driven by the momentum transfer from a high…

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Electrum Wallet

Electrum is a long-standing Bitcoin wallet, first released by Thomas Voegtlin in 2011 and distributed under the MIT license. Rather…

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Elliptic Curve Cryptography (ECC)

Elliptic Curve Cryptography (ECC) is a family of public-key schemes whose security rests on the algebraic structure of elliptic curves…

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Elliptic Curve Diffie-Hellman (ECDH)

Elliptic Curve Diffie-Hellman (ECDH) is a key-agreement protocol that lets two parties, each holding an elliptic-curve key pair, compute an…

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Elliptic Curve Pairing

An elliptic curve pairing is a bilinear map that takes two points from elliptic-curve groups and outputs an element in…

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Elliptic Curve Point Multiplication

Elliptic curve point multiplication, also called scalar multiplication, is the core operation of every ECC system. Given a point P…

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Eltoo

Eltoo, also known as LN-Symmetry, is a proposed redesign of how Lightning payment channels enforce their current balance. In today's…

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Eltoo (LN-Symmetry)

Eltoo, also called LN-Symmetry, is a proposed replacement for the Lightning Network's channel-update mechanism in which any later channel state…

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Embedding Dimension

The embedding dimension (or vector dimensionality) is simply the number of numeric values used to represent each item in an…

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Embeddings

An embedding is a list of numbers, a vector, that represents a piece of data such as a word, sentence,…

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Emergent Abilities

Emergent abilities are capabilities that are absent in smaller models but appear in larger ones, such that they cannot be…

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EMI Shielding

EMI shielding is a conductive barrier that blocks electromagnetic interference from escaping a noisy circuit or reaching a sensitive one.…

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eMMC

eMMC (embedded MultiMediaCard) is a self-contained flash-storage package that pairs NAND flash with an on-chip controller in a single soldered-down…

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Empty Block

An empty block is a fully valid Bitcoin block that includes only its coinbase transaction and no user transactions —…

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Encoder-Decoder Architecture

The encoder-decoder architecture is a neural network design built from two cooperating components: an encoder that compresses an input into…

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End-to-End Encryption (E2EE)

End-to-end encryption (E2EE) is a method of securing communication so that a message is encrypted by its original sender and…

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Ephemeral Anchors

Ephemeral anchors are a Bitcoin relay-policy refinement that creates a clean, contention-free way to fee-bump multi-party transactions such as Lightning…

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Episodic vs Semantic Memory (AI)

Episodic and semantic memory are two categories of long-term memory that AI agent designers borrow from cognitive psychology, where Endel…

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Epoch

Intermediate

A 2,016-block period between difficulty adjustments. Each epoch lasts roughly two weeks.

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Epoch (Training)

In model training, an epoch is one complete pass of the entire training dataset through the learning algorithm. During a…

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Equal-Output CoinJoin

An equal-output CoinJoin is the most common privacy-preserving collaborative transaction structure on Bitcoin. Participants agree on a uniform output value,…

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Erlay (BIP330)

Erlay is a proposed bandwidth-efficient transaction-relay protocol for Bitcoin, specified in BIP330. Today, nodes announce every unconfirmed transaction to every…

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ESD (Electrostatic Discharge)

Electrostatic discharge (ESD) is the rapid transfer of static charge between two objects at different electrical potentials. To a technician…

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ESD Protection

Electrostatic discharge (ESD) protection is the set of on-chip structures that defend an integrated circuit from sudden, high-voltage charge transfers.…

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ESP32

Intermediate

A low-cost microcontroller powering open-source miners like Bitaxe. Handles WiFi, firmware, and chip control.

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Eutectic Solder

A eutectic solder is an alloy mixed at the precise ratio that melts and solidifies at one single temperature, passing…

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EUV Lithography

EUV (extreme ultraviolet) lithography is the chip-patterning technique that uses light with a wavelength of just 13.5 nanometers to print…

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Evil Maid Attack

An evil maid attack is a physical-access attack in which an adversary tampers with a device left briefly unattended, then…

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EXL2 (ExLlamaV2 format)

EXL2 is the quantization format used by ExLlamaV2, a fast inference library for running large language models on consumer-class GPUs.…

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ExLlamaV2

ExLlamaV2 is an open-source inference library built for running large language models locally on consumer-class GPUs. It is the successor…

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Expert Parallelism

Expert parallelism is a parallelization strategy built specifically for Mixture-of-Experts (MoE) architectures. An MoE layer contains many small sub-networks called…

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Extended Public Key (xpub / ypub / zpub)

An extended public key, almost always written as an xpub, is a BIP32 public key bundled with its chain code.…

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Extranonce

The extranonce is additional search space that lives inside a block's coinbase transaction, used by miners once the 32-bit nonce…

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F

F2Pool

F2Pool is one of the longest-running Bitcoin mining pools, co-founded in 2013 by Chun Wang and Mao Shihang. It is…

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Factory Reset (ASIC Miner)

A factory reset returns an ASIC miner's software configuration to its out-of-the-box defaults. It clears the pool configuration, custom passwords,…

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Fan Curve

A fan curve is the relationship between a cooling fan's speed and a control input, almost always chip temperature, defined…

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Faraday Bag

A Faraday bag is a portable, flexible version of a Faraday cage: a pouch lined with conductive material that blocks…

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FATF Travel Rule

The FATF Travel Rule is the crypto-specific application of the Financial Action Task Force's Recommendation 16, which requires that originator…

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Feather Fork

A feather fork is a censorship strategy that lets a miner with well under half the network's hashrate pressure others…

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Feature Store

A feature store is a centralized repository for the engineered inputs — the features — that machine-learning models consume. It…

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Federated Peg

A federated peg is the trust model that lets bitcoin move between the main chain and a sidechain without changing…

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Federation (Bitcoin)

In Bitcoin, a federation is a fixed set of independent operators who collectively control funds or a secondary network through…

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Fedimint

Fedimint is an open-source protocol for running federated Chaumian ecash mints on Bitcoin. It lets a community establish a trust-minimized,…

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Fee Estimation

Fee estimation is the process by which a wallet predicts the feerate a transaction needs to confirm within a desired…

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Fee Rate (sat/vB)

Fee rate, quoted in satoshis per virtual byte (sat/vB), is the price a sender offers for each unit of block…

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Fee Sniping

Fee sniping is a mining strategy in which a miner deliberately re-mines one or more of the most recent blocks…

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Feed-in Tariff

A feed-in tariff (FIT) is a policy mechanism that guarantees producers of renewable electricity a fixed payment for every kilowatt-hour…

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Feeler Connection

A feeler connection is a short-lived, single test connection that a Bitcoin Core node opens roughly once every two minutes…

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Ferrite Bead

A ferrite bead is a small passive component that suppresses high-frequency electrical noise by converting it into a tiny amount…

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Few-Shot Prompting

Few-shot prompting is a technique in which you include a small number of worked examples — typically two to a…

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Fiat Currency

Fiat currency is money that a government has declared to be legal tender but that is not backed by or…

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Fidelity Bond

A fidelity bond is a mechanism in which Bitcoin value is deliberately sacrificed or locked up to make a cryptographic…

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Fine-Tuning

Fine-tuning is the process of taking a model that has already been pretrained on a broad corpus and continuing to…

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FinFET

A FinFET (fin field-effect transistor) is a non-planar, three-dimensional transistor in which the conducting channel is raised into a thin…

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Finite Field

A finite field, also called a Galois field, is a number system containing a finite number of elements in which…

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Finney Attack

A Finney attack is a double-spend technique against merchants who accept zero-confirmation payments, named after early Bitcoin contributor Hal Finney,…

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FINTRAC (for Bitcoin Miners)

FINTRAC — the Financial Transactions and Reports Analysis Centre of Canada — is Canada's federal anti-money-laundering and counter-terrorist-financing regulator. It…

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Firewall

A firewall is a device or piece of software that enforces an access-control policy between networks, deciding which packets may…

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Firmware

Beginner

The software running on a miner that manages hashing, pool connections, and hardware monitoring.

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Firmware Dev Fee

A firmware dev fee is the compensation that makers of custom ASIC firmware collect for their work, taken not as…

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Firmware Flashing (ASIC Miner)

Firmware flashing is the process of writing a complete firmware image onto an ASIC miner's control board, overwriting the operating…

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First-Seen-Safe Rule

The first-seen rule, sometimes called first-seen-safe, is the default mempool policy in Bitcoin Core: when a node receives two transactions…

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Flare Gas Mining

Flare gas mining places Bitcoin miners directly at oil and gas wellheads, running them on electricity produced from associated gas…

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Flared Gas Mining (Flare Mitigation)

Flared gas mining is the practice of siting Bitcoin miners directly on an oil-and-gas well pad and powering them with…

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Flash Attention

Flash Attention is a fast, memory-efficient algorithm for computing the attention operation at the heart of every transformer model. It…

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Flip Chip

Flip chip, also called controlled-collapse chip connection or C4, is an interconnect method in which the active face of a…

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FLOPS (Floating-Point Operations Per Second)

FLOPS stands for floating-point operations per second and is the standard unit for expressing the raw arithmetic throughput of a…

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FLOPS (Floating-Point Operations per Second)

FLOPS (floating-point operations per second) is the standard measure of a processor's raw arithmetic throughput — how many floating-point calculations…

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Flowise

Flowise is an open-source, low-code tool that provides a drag-and-drop interface for building applications powered by large language models. Written…

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Flux

Flux is a chemical cleaning agent that makes good soldering possible. Its core job is twofold: it dissolves the metal…

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Flux Activator

A flux activator is the chemically aggressive ingredient inside a soldering flux that actually does the work of stripping oxides…

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FOMO

FOMO stands for "Fear Of Missing Out." In cryptocurrency it describes the anxiety participants feel when an asset is rising…

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Fork

Intermediate

A split in the blockchain into two paths. Can be temporary from competing blocks or permanent from rule changes.

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Fork-After-Withholding (FAW) Attack

The fork-after-withholding (FAW) attack, introduced in 2017 research, fuses a block withholding attack with the deliberate forking logic of selfish…

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Forward Proxy

A forward proxy is a server that sits between a group of clients and the wider internet, making outbound requests…

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Forward Secrecy

Forward secrecy, also called perfect forward secrecy (PFS), is a property of key-agreement protocols guaranteeing that recorded encrypted sessions cannot…

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Foundation Model

A foundation model is, in the definition coined by Stanford's Center for Research on Foundation Models in 2021, any model…

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Foundation Passport

Passport is a Bitcoin-only hardware wallet made by Foundation Devices. It is designed to operate air-gapped: the device has no…

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Foundry

A foundry, or fab, is the factory that physically manufactures integrated circuits. In the pure-play foundry model, the foundry owns…

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Foundry USA Pool

Foundry USA Pool is a Bitcoin mining pool operated by Foundry Digital LLC, a subsidiary of Digital Currency Group (DCG).…

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FP16 / INT8 Precision

FP16 and INT8 are two of the lower-precision number formats used to store and compute the weights and activations inside…

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FP8

FP8 is an 8-bit floating-point format used to push neural-network training and inference below the 16-bit precision of BF16. Because…

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FPGA (Field-Programmable Gate Array)

An FPGA (Field-Programmable Gate Array) is an integrated circuit built from a grid of configurable logic blocks and programmable interconnects,…

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FPPS

Intermediate

A pool payout method paying miners a fixed rate per share including estimated transaction fees.

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Fractional Reserve Banking

Fractional reserve banking is the dominant model of modern commercial banking, in which a bank keeps only a small fraction…

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Free Cooling

Free cooling is any cooling strategy that rejects heat using naturally cold ambient air or water instead of, or before,…

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Frequency Hopping (FHSS)

Frequency-hopping spread spectrum (FHSS) transmits a signal by rapidly switching the carrier frequency among many channels spread across a wide…

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Frequency Regulation

Frequency regulation is the ancillary service that keeps a power grid's alternating-current frequency locked to its nominal target — 60…

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Fresnel Zone

A Fresnel zone is one of a series of concentric, ellipsoidal regions surrounding the straight line-of-sight path between two antennas.…

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FRI Protocol

FRI, short for Fast Reed-Solomon Interactive Oracle Proof of Proximity, is a protocol that proves a committed set of values…

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Frontier Model

A frontier model is a highly capable, general-purpose AI model that sits at the cutting edge of what is currently…

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FROST

FROST, short for Flexible Round-Optimized Schnorr Threshold, is a threshold signing protocol in which any t out of n participants…

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FUD

FUD stands for "Fear, Uncertainty, and Doubt." In cryptocurrency communities it refers to negative, misleading, or exaggerated information that spreads…

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Full Node

A full node is a Bitcoin client that downloads every block and transaction, independently verifies them against the network's consensus…

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Fully Sharded Data Parallel (FSDP)

Fully Sharded Data Parallel (FSDP) is PyTorch's memory-efficient evolution of data parallelism. Where standard DistributedDataParallel keeps a full copy of…

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Function Calling

Function calling, also known as tool use, is the mechanism that lets a language model interact with external code and…

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Functionary

A functionary is one of the specialized physical devices that operate and secure a federated Bitcoin sidechain like Liquid. Each…

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G

GAAFET (Gate-All-Around)

A GAAFET (gate-all-around field-effect transistor) is the successor to the FinFET, in which the gate completely encircles the channel on…

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Gallium Nitride (GaN)

Gallium Nitride (GaN) is a wide-bandgap semiconductor increasingly used in the power transistors of high-density switching supplies. With a bandgap…

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Gap Limit

The gap limit is the rule a hierarchical deterministic wallet uses to decide when to stop scanning for funds. Because…

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Garage Mining

Beginner

Running miners in a home garage for noise isolation and easy access. A popular choice for residential mining.

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Gated Linear Attention

Gated linear attention (GLA) is a refinement of linear attention that adds data-dependent gating to the model's recurrent state. Plain…

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GEMM (General Matrix Multiply)

GEMM, short for General Matrix Multiply, is the core dense linear-algebra operation defined as C = αAB + βC, where…

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Generative Adversarial Network (GAN)

A generative adversarial network (GAN) is a generative model, introduced by Ian Goodfellow and colleagues in 2014, built from two…

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Generative Adversarial Network (GAN)

A Generative Adversarial Network (GAN) is a generative machine-learning architecture, introduced by Ian Goodfellow and colleagues in 2014, in which…

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Generator (Genset)

A generator set, or genset, is a self-contained package that pairs a fuel-burning engine with an electrical alternator to produce…

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Generator Point

The generator point, often called the base point and written G, is a single fixed point on the secp256k1 curve…

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Genesis Block

The genesis block is the very first block of the Bitcoin blockchain, block 0, mined by Satoshi Nakamoto on January…

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Genesis Block Headline

The genesis block headline is the line of text Satoshi Nakamoto embedded in the coinbase parameter of Bitcoin's first block…

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Genset Synchronization

Genset synchronization is the process of safely connecting a generator to an energized bus, or to another running generator, so…

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Geothermal Mining

Geothermal mining is Bitcoin mining powered by electricity derived from the Earth's internal heat. Geothermal power plants drill wells deep…

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getblocktemplate (GBT)

getblocktemplate, abbreviated GBT, is the Bitcoin Core RPC method that returns everything a miner needs to construct a block to…

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Getwork

Advanced

An older, less efficient mining protocol replaced by Stratum. Required frequent polling for new work.

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GGUF

GGUF (GGML Universal Format) is a binary file format for storing large language models so they can be run efficiently…

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GMRS (General Mobile Radio Service)

GMRS (General Mobile Radio Service) is a licensed two-way radio service in the United States operating on channels around 462…

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Golden Nonce

A golden nonce is the rare nonce value that, when combined with the rest of the block header and run…

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Goodput (LLM Serving)

Goodput is the performance metric that tells a large language model operator how much useful work their server can actually…

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GPIO (General-Purpose Input/Output)

GPIO stands for general-purpose input/output: uncommitted digital pins on a processor or microcontroller whose direction and state are set by…

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GPL (GNU General Public License)

The GNU General Public License (GPL) is the most widely used strong copyleft software license, authored by the Free Software…

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GPQA (Graduate-Level Google-Proof Q&A)

GPQA (Graduate-Level Google-Proof Q&A) is a benchmark introduced in 2023 by David Rein and colleagues to test deep reasoning in…

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GPTQ

GPTQ (Generative Pre-trained Transformer Quantization) is a one-shot, post-training quantization method that compresses large language model weights down to 3…

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GPU Kernel

A GPU kernel is a function written in a serial style that the GPU executes simultaneously across many threads. In…

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GPUDirect RDMA

GPUDirect RDMA is an NVIDIA technology that lets a network adapter or other PCIe peer device transfer data directly to…

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Gradient Accumulation

Gradient accumulation lets you train with a large effective batch size when your hardware cannot hold one in memory. Instead…

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Gradient Checkpointing

Gradient checkpointing, also called activation checkpointing, is a technique that trades extra computation for reduced memory. During an ordinary forward…

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Gradient Clipping

Gradient clipping constrains how large gradients can grow during backpropagation, guarding against the exploding-gradient problem. In deep networks, gradients are…

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Gradient Descent

Gradient descent is the optimization method that actually trains a neural network. Backpropagation computes the gradient of the loss with…

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Grammar-Constrained Decoding

Grammar-constrained decoding restricts a language model's next-token choice to only those tokens that keep the partial output valid against a…

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GrapheneOS

GrapheneOS is a free, open-source, privacy- and security-focused mobile operating system built on the Android Open Source Project (AOSP). Developed…

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Great Mining Migration

The Great Mining Migration refers to the mass relocation of Bitcoin mining hardware out of China in 2021, triggered by…

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Greedy Decoding

Greedy decoding is the simplest text-generation strategy for a language model: at every step it selects the single token with…

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Gresham’s Law

Gresham's law is the economic observation that "bad money drives out good." When two forms of money are required by…

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Grid Interconnection

Grid interconnection is the formal, regulated process by which a new power generator, or a large new consumer of power…

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Grid Mix

Grid mix is the combination of generation sources supplying electricity to a given grid at a given time: hydro, natural…

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Grid-Following Inverter

A grid-following inverter is the conventional grid-tied converter found in most solar and battery installations. It controls the AC-side current…

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Grid-Forming Inverter

A grid-forming inverter is a power-electronic converter that controls the AC-side voltage waveform directly, behaving as a voltage source that…

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Grokking

Grokking is a training phenomenon in which a neural network first memorizes its training data — reaching near-perfect training accuracy…

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Ground Fault

A ground fault is an unintentional electrical path between an energized (hot) conductor and a grounded surface earth, a metal…

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Ground Plane

A ground plane is a large, continuous area of copper, usually a full inner layer of a multilayer board, that…

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Ground Truth / Labeled Data

Ground truth is the set of known-correct answers a supervised machine-learning model learns from and is measured against. Each training…

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Grouped-Query Attention (GQA)

Grouped-Query Attention (GQA) is an attention mechanism that interpolates between two extremes: full multi-head attention, where every query head owns…

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Grouped-Query Attention (GQA)

Grouped-query attention (GQA) is a memory-saving form of self-attention introduced in a 2023 Google paper by Ainslie and colleagues. It…

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GRPO (Group Relative Policy Optimization)

Group Relative Policy Optimization (GRPO) is a reinforcement-learning algorithm introduced by DeepSeek in its DeepSeekMath work and later used to…

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GSM8K (Grade School Math Benchmark)

GSM8K (Grade School Math 8K) is a benchmark released by OpenAI in 2021 to measure multi-step mathematical reasoning. It contains…

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GST/HST on Crypto Mining (Canada)

Goods and Services Tax / Harmonized Sales Tax (GST/HST) treatment is one of the more surprising corners of Canadian crypto-mining…

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Guardrails (LLM)

Guardrails are programmable rules and constraints placed around a large language model at runtime to keep its behaviour safe, on-topic,…

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H

Hallucination (LLM)

A hallucination is an output from a language model that sounds plausible and confident but is factually incorrect, fabricated, or…

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Halving

Beginner

The event that cuts Bitcoin's block reward in half every four years, enforcing digital scarcity.

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Hard Fork

Advanced

A non-backward-compatible protocol change requiring all nodes to upgrade. Can permanently split the chain.

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Hard Money

Hard money is a form of money whose supply is difficult and expensive to increase, making it resistant to debasement…

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Hardened Derivation

Hardened derivation is a BIP32 safety mechanism used when deriving child keys at indices 2^31 and above. In wallet paths…

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Hardware Backdoor

A hardware backdoor is a covert access mechanism embedded in the physical components of a device or in its low-level…

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Hardware Wallet

A hardware wallet is a purpose-built physical device whose only job is to generate, store, and use Bitcoin private keys…

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Harmonics

Harmonics are voltage or current components at integer multiples of the fundamental line frequency, for example 180 Hz (3rd) and…

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Hash

Beginner

The output of a cryptographic function. Miners search for block hashes below the difficulty target.

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Hash Cost

Intermediate

The cost to produce one terahash of mining power. Mining is profitable when hash price exceeds hash cost.

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Hash Engine

A hash engine (also called a hashing core) is the elementary compute block inside a Bitcoin mining ASIC that physically…

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Hash Price

Intermediate

Revenue per terahash per day. A key metric showing the economic value of mining power at any given time.

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Hash Ribbon

The Hash Ribbon is an on-chain market indicator that reads the health of Bitcoin's mining sector through its hashrate. Created…

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HASH160

HASH160 is the two-step hashing operation Bitcoin uses to turn a public key (or a script) into a short, fixed-length…

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Hashboard

Intermediate

The main mining board inside an ASIC containing rows of mining chips. Most miners have 3-4 hashboards.

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Hashboard Repair

Intermediate

Fixing malfunctioning hashboards by replacing failed chips and components to restore full mining performance.

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Hashcenter

Hashcenter is D-Central's term for a compute facility purpose-built around hash-dense or inference-dense workloads — Bitcoin ASIC mining, GPU-based AI…

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Hashprice

Hashprice is the single most important unit of measure for a Bitcoin miner's revenue: it expresses how much a given…

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Hashprice NDF (Non-Deliverable Forward)

A hashprice non-deliverable forward (NDF) is a cash-settled contract whose value tracks Bitcoin mining hashprice rather than requiring any actual…

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Hashrate

Beginner

The speed at which a mining device performs calculations. More hashrate equals more mining power.

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Hashrate Derivative

A hashrate derivative is a financial contract whose value is tied to the economics of Bitcoin mining rather than to…

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Hashrate Forward Contract

A hashrate forward contract is an over-the-counter (OTC) agreement in which a miner commits to deliver a fixed quantity of…

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Hashrate Futures

Hashrate futures are standardized derivative contracts whose settlement value is tied to the Bitcoin network's mining output, usually approximated through…

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Hashrate Marketplace

A hashrate marketplace is a venue, typically over-the-counter, where Bitcoin mining capacity and the revenue it produces are traded as…

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Hashrate Units (TH/s, PH/s, EH/s)

Hashrate units express how many SHA-256 computations a miner or the whole network performs each second. The base unit is…

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Haystack

Haystack is an open-source AI orchestration framework built by deepset for creating production-ready LLM applications in Python. Its core abstraction…

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HBM (High-Bandwidth Memory)

High-Bandwidth Memory (HBM) is a JEDEC-standard memory technology that stacks DRAM dies vertically and connects them to the processor over…

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Header-Only Mining

Header-only mining (HOM) is the Stratum V2 mode used on standard channels, where a hashing device works only on the…

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Headers-First Sync

Headers-First Sync is the initial-block-download strategy Bitcoin Core has used since version 0.10.0. Rather than walking the chain one full…

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Heat Exchanger

A heat exchanger is a device that transfers thermal energy between two fluid streams without letting them mix. It is…

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Heat Pump (COP)

A heat pump is a device that moves heat from one place to another rather than creating it by burning…

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Heat Rate

Heat rate is the standard measure of how efficiently a thermal power plant converts fuel into electricity. It expresses the…

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Heat Recovery

Beginner

Capturing miner heat for productive use like home heating. Makes mining economics much more favorable in cold climates.

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Heat Reuse

Heat reuse (or waste-heat recovery) is the practice of capturing the thermal energy a Bitcoin miner produces and putting it…

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Heatsink

Beginner

A metal component that absorbs and dissipates heat from mining chips, critical for performance.

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Heaviest Chain Rule

The Heaviest Chain Rule is a fork-choice rule that selects the branch supported by the most observed work across an…

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Hierarchical Navigable Small World (HNSW)

Hierarchical Navigable Small World (HNSW) is the most widely used graph-based index for approximate nearest neighbor search, and the default…

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High Bandwidth Memory (HBM)

High Bandwidth Memory (HBM) is a memory architecture that stacks multiple DRAM dies vertically and places them directly beside the…

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HODL

HODL is a deliberately preserved misspelling of "hold" that has become one of Bitcoin's most recognizable cultural terms. It describes…

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HODL Waves

HODL Waves are a visualization of Bitcoin's circulating supply grouped by the age of its unspent transaction outputs (UTXOs). The…

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Home Mining

Beginner

Mining Bitcoin at home. Requires managing noise, heat, and power while potentially heating your space.

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Hop Limit (Meshtastic)

The hop limit is a Meshtastic LoRa configuration value that controls how far a packet travels across the mesh before…

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Hot Air Rework Station

A hot air rework station is a bench tool that blows a controlled stream of heated air through a nozzle…

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Hot Aisle / Cold Aisle

Hot aisle / cold aisle is the foundational airflow layout for any air-cooled Hashcenter or data center. Rows of ASIC…

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Hot Tweezers

Hot tweezers are a soldering tool with two independently heated, tweezer-style tips that close on a small surface-mount component and…

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Hot Wallet

A hot wallet is a Bitcoin wallet running on a device that is connected to the internet, typically an app…

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HTLC (Hashed Timelock Contract)

A Hashed Timelock Contract (HTLC) is the conditional payment primitive at the heart of every Lightning Network transaction. It locks…

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Hugging Face Hub

The Hugging Face Hub is the de facto public repository for open machine learning, hosting over two million models, more…

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Human-in-the-Loop (AI)

Human-in-the-loop, or HITL, is the deliberate placement of human oversight at critical decision points inside an otherwise autonomous AI workflow.…

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HumanEval

HumanEval is a code-generation benchmark released by OpenAI in 2021 alongside the Codex paper. It contains 164 hand-written Python programming…

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Hybrid Attention

Hybrid attention describes architectures that deliberately mix two kinds of sequence-mixing layers: a small number of expensive full-attention layers and…

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Hybrid Search

Hybrid search runs two complementary retrieval strategies in parallel and merges their results: a sparse keyword search (typically BM25) and…

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Hydro Cooling

Hydro cooling (water cooling) removes heat from an ASIC miner by running coolant — typically deionized water or a water-glycol…

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Hydroelectric Mining

Hydroelectric mining runs ASIC fleets on electricity from hydropower dams and run-of-river stations. Hydropower is a long-established, low-marginal-cost source, and…

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Hyperbitcoinization

Hyperbitcoinization is a term coined by Daniel Krawisz in a 2014 essay for the Satoshi Nakamoto Institute to describe a…

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Hyperparameter

A hyperparameter is a configuration value you set before training begins, which governs how a model learns rather than what…

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I

I2C Bus

The I2C bus (Inter-Integrated Circuit, pronounced "I-squared-C") is a two-wire serial bus that lets one controller talk to many low-speed…

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I2P (Invisible Internet Project)

I2P, the Invisible Internet Project, is a free, open-source anonymity network built as a self-contained overlay on top of the…

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IEC 60320 C13 / C14 Connector

The IEC 60320 C13 and C14 form the most common appliance coupler in computing and small mining hardware. The C14…

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IEC 60320 C19 / C20 Connector

The IEC 60320 C19 and C20 are the larger, higher-current siblings of the familiar C13/C14 pair. The C20 is the…

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Image Embedding

An image embedding is a fixed-length vector of numbers that encodes the visual content of an image. A neural network,…

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Image Patch Embedding

Image patch embedding is the operation that converts a raw image into a sequence of vectors a transformer can read.…

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Immersion Cooling

Advanced

Submerging mining hardware in non-conductive liquid for silent, efficient cooling. Eliminates fans and dust.

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Immersion Tank

Advanced

A sealed container of cooling fluid for silent mining. Eliminates fans and enables overclocking.

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Importance Matrix (imatrix)

An importance matrix, often shortened to imatrix, is a calibration artifact used by llama.cpp to improve the quality of quantized…

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In-Context Learning

In-context learning (ICL) is the ability of a large language model to perform a new task purely from information in…

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In-Flight Batching

In-flight batching is a request-scheduling technique used by self-hosted LLM inference servers to keep a GPU fully occupied while generating…

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Inbound Liquidity

Inbound liquidity is the amount of Bitcoin parked on the remote side of your Lightning channels, which determines how much…

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Indirect Prompt Injection

Indirect prompt injection is an attack in which an adversary plants malicious instructions inside external content that a large language…

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Inductor

An inductor is a passive two-terminal component, usually a coil of wire around a magnetic core, that stores energy in…

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Inference

Inference is the stage at which a trained machine-learning model is actually used: it receives an input (such as a…

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Inference Endpoint

An inference endpoint is the network-addressable interface through which a deployed model receives input and returns predictions. In practice it…

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InfiniBand

InfiniBand is an open-standard, high-speed, low-latency interconnect technology used to network servers, storage, and accelerators in high-performance computing and large…

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Inflation

Inflation is a sustained increase in the general price level across an economy, meaning that over time the same amount…

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Initial Block Download (IBD)

Initial Block Download (IBD) is the one-time process a brand-new Bitcoin full node performs when it first comes online: downloading…

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Input Registration

Input registration is the opening phase of a coordinated CoinJoin round. Each participant selects which of their unspent outputs (UTXOs)…

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Inrush Current

Inrush current is the instantaneous peak current that floods into a device the moment it is energized. In a switch-mode…

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Inscriptions

An inscription is arbitrary content, such as an image, text, or JSON, stored directly on the Bitcoin blockchain inside a…

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Interconnection Queue

The interconnection queue is the formal waitlist of projects — both new generation and large new loads — applying for…

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Interleaved Image-Text

Interleaved image-text refers to content in which images and text alternate within a single sequence, the way an illustrated blog…

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Intermetallic Compound

An intermetallic compound (IMC) is the thin metallurgical layer that forms at the boundary where molten solder meets a copper…

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Interruptible Load

Interruptible load is demand that an end-use customer makes available to its utility or load-serving entity for curtailment, via contract…

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Inverted File Index (IVF)

An inverted file index (IVF) is a partitioning scheme that makes vector search scale to billions of items. At build…

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Inverter

An inverter is a power-electronics device that converts direct current (DC) into alternating current (AC) at a required voltage and…

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IP Reporter

IP Reporter is a small Windows utility published by Bitmain that lets you discover an Antminer's network address without scanning…

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ISM Band

An ISM band (Industrial, Scientific, and Medical band) is a portion of radio spectrum that the International Telecommunication Union has…

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Iterative DPO

Iterative DPO is the practice of running Direct Preference Optimization not once over a fixed dataset, but in repeated rounds,…

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J

J/TH (Joules per Terahash)

J/TH — joules per terahash — is the standard efficiency metric for Bitcoin ASIC miners. It expresses how much energy…

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Jailbreak (LLM)

A jailbreak is a crafted prompt that bypasses the safety guardrails of a large language model (LLM), causing it to…

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Jamba

Jamba is a hybrid large language model that interleaves three building blocks: Mamba state-space layers, transformer attention layers, and mixture-of-experts…

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Jan (app)

Jan is an open-source desktop application that runs large language models locally on a user's own computer, positioned as a…

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JIT Channel (Just-In-Time)

A Just-In-Time (JIT) channel is one that a Lightning Service Provider opens in direct response to an incoming payment destined…

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Job Declaration Protocol

The Job Declaration Protocol (JDP) is the Stratum V2 sub-protocol that hands block-template construction back to the miner. Under legacy…

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Job Declaration Protocol (Stratum V2)

The Job Declaration Protocol is the part of Stratum V2 that returns transaction-selection power to the people running the hardware.…

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Job Declarator

The Job Declarator is the moving part of Stratum V2 that actually carries a miner's transaction choices to the pool…

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JoinMarket

JoinMarket is open-source software for building CoinJoin transactions, with an incentive structure designed to make collaborative privacy practical. It creates…

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JSON Mode

JSON mode is a generation setting that forces a language model to return output that parses as valid JSON. It…

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JTAG (Joint Test Action Group)

JTAG is a hardware debug standard defined by IEEE 1149.1 that exposes a small serial interface (TCK, TMS, TDI, TDO,…

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K

K-quants (llama.cpp)

K-quants are a family of quantization formats in llama.cpp, the GGUF-based ecosystem, denoted by names such as Q4_K_M, Q5_K_S, and…

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Kali Linux

Kali Linux is a free, open-source, Debian-based Linux distribution built for penetration testing, security auditing, and digital forensics. It is…

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Kernel Log

The kernel log is the most detailed diagnostic source on an ASIC miner, recording what the firmware sees as it…

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Key Ceremony

A key ceremony is a structured, deliberate procedure for generating cryptographic keys, and distributing any resulting shares, under controlled conditions…

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Key Path vs Script Path Spend

Every Taproot output can be unlocked two different ways, and the chooser picks at spending time. The key path is…

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Keyoxide

Keyoxide is free, open-source software for building and verifying decentralized online identities. A Keyoxide profile is a collection of identity…

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Keysend

Keysend is a Lightning Network feature that lets one node push a payment directly to another node's public key without…

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KL Penalty (KL Divergence)

The KL penalty is a regularization term used throughout reinforcement-learning fine-tuning of language models. It measures the Kullback-Leibler (KL) divergence,…

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Knowledge Distillation

Knowledge distillation is a model-compression technique that transfers the behaviour of a large, capable teacher model into a smaller, cheaper…

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Knowledge Graph

A knowledge graph is a structured representation of information in which real-world entities (people, devices, miners, firmware versions) are stored…

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KoboldCpp

KoboldCpp is an open-source, easy-to-use AI text-generation tool that builds on top of llama.cpp. It is distributed as a single…

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Krux

Krux is open-source firmware, developed under the selfcustody project, that turns inexpensive off-the-shelf Kendryte K210 boards, such as the Maix…

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KTO (Kahneman-Tversky Optimization)

KTO (Kahneman-Tversky Optimization) is a method for aligning large language models that learns from a single binary label per response…

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KV Cache (Key-Value Cache)

The KV cache, short for key-value cache, is the working memory that makes autoregressive text generation practical. During inference, a…

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KV Cache Quantization

KV cache quantization reduces the memory footprint of long-context inference by storing cached attention keys and values in low-precision integer…

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kVA (Apparent Power)

kVA, or kilovolt-amperes, measures the apparent power an alternating-current load pulls from the supply. It is the vector sum of…

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kVAR (Reactive Power)

kVAR, kilovolt-amperes reactive, quantifies reactive power the portion of alternating-current power that flows back and forth between source and load…

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KYC (Know Your Customer)

Know Your Customer (KYC) is the identity-verification process that regulated financial institutions and cryptocurrency exchanges are required to perform before…

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KZG Polynomial Commitment

The KZG polynomial commitment, named after Kate, Zaverucha, and Goldberg, is a pairing-based scheme that commits to a polynomial with…

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L

Landfill Gas Mining

Landfill gas mining powers ASIC miners with electricity made from methane captured at municipal landfills or biogas facilities. As buried…

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LangChain

LangChain is an open-source framework for building applications on top of large language models, including agents that can call tools…

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LangGraph

LangGraph is an open-source orchestration framework and runtime, developed by the LangChain team, for building stateful and long-running AI agents.…

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Laser Eyes

"Laser eyes" refers to a Bitcoin social-media meme in which people edit glowing red beams onto the eyes of their…

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Latch-Up

Latch-up is a destructive failure mode unique to CMOS in which an unintended low-impedance path forms directly between the power…

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Late Interaction (ColBERT)

Late interaction is a retrieval architecture, popularized by the ColBERT model (Khattab and Zaharia, 2020), that sits between cheap single-vector…

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Latent Space

A latent space is the abstract, lower-dimensional space in which a machine-learning model represents the compressed, essential features of its…

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Law 25 (Quebec)

Law 25 is the common name for Quebec's Act to modernize legislative provisions as regards the protection of personal information,…

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Layer Normalization

Layer normalization, introduced by Ba, Kiros, and Hinton in 2016, is a technique that stabilizes neural network training by re-scaling…

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Lazy Consensus

Lazy consensus is the informal decision-making model used by the Bitcoin Core project. There is no formal voting, no board,…

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Leakage Current

Leakage current is the current that flows through a transistor when it is nominally 'off' and not actively switching. It…

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Ledger

Ledger is a manufacturer of hardware wallets, including the Nano and Stax model lines, that store private keys offline and…

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Lender of Last Resort

The lender of last resort is the function, usually performed by a central bank, of providing emergency liquidity to financial…

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Lifted Pad

A lifted pad is a copper landing pad that has separated from the laminate surface of the circuit board it…

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Lightning Address

A Lightning Address is an email-like identifier in the form username@domain.com that anyone can pay over the Lightning Network without…

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Lightning Dev Kit (LDK)

The Lightning Dev Kit (LDK) is a complete Lightning Network implementation delivered as a software development kit rather than a…

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Lightning Invoice (BOLT11)

A Lightning invoice in the BOLT11 format is a single bech32-encoded string that encodes everything a sender needs to make…

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Lightning Network

Intermediate

A Layer 2 protocol enabling fast, cheap Bitcoin payments through off-chain payment channels.

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Lightning Service Provider (LSP)

A Lightning Service Provider (LSP) is a business or node operator that helps users connect to and transact on the…

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Lightning Terminal (litd)

Lightning Terminal (litd, also written LiT) is a browser-based application from Lightning Labs for managing Lightning Network channel liquidity. It…

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Lindy Effect

The Lindy Effect (also called Lindy's Law) holds that for non-perishable things — ideas, technologies, books, or cultural artifacts —…

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Line of Sight

Line of sight (LOS) is the direct, unobstructed path between a transmitting and receiving antenna. At the VHF, UHF, and…

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Linear Attention

Linear attention is a family of attention mechanisms that reduce the cost of self-attention from quadratic to linear in the…

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Link Budget

A link budget is the full accounting of every gain and loss along a radio path, used to predict the…

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Linux distribution

A Linux distribution (or distro) is a complete operating system assembled from the Linux kernel together with the additional software…

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Liquid Network

The Liquid Network is a Bitcoin sidechain launched by Blockstream in 2018 and governed by an open federation of exchanges,…

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Liquidity

Liquidity is the ease with which an asset can be bought or sold without significantly moving its price. A highly…

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Liquidity Ads

Liquidity ads are a way for Lightning nodes to advertise, directly over the network's gossip layer, that they are willing…

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llama.cpp

llama.cpp is an open-source inference engine, written primarily in C and C++, that runs large language models (LLMs) entirely on…

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LLC Resonant Converter

The LLC resonant converter is the isolated DC-DC stage found in most modern high-efficiency ASIC and server power supplies. It…

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LM Studio

LM Studio is a free desktop application for discovering, downloading, and running open-weight large language models entirely on your own…

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LND (Lightning Network Daemon)

LND (Lightning Network Daemon) is one of the most widely deployed implementations of a full Lightning Network node. Written in…

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LNURL

LNURL is a family of open standards (the LUD series) that wrap interactions with a Lightning service inside a bech32-encoded…

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LNURL-auth

LNURL-auth is the LNURL subprotocol (LUD-04) that turns a Lightning wallet into a password-free login credential. Instead of a username…

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Load Balancer

A load balancer is a network component that distributes incoming requests across a pool of backend servers so that no…

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Load Factor

Load factor is the ratio of average electrical demand to peak demand over a billing period, expressed as a number…

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Load Following

Load following is the practice of increasing and decreasing generation over a period of many minutes to hours to track…

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Local LLM

Local LLM is a large language model deployed on hardware under your direct control — a personal computer, a server…

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Locktime (nLockTime)

Locktime (the nLockTime field) is a 4-byte value at the end of every Bitcoin transaction that specifies the earliest point…

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Logic Analyzer

A logic analyzer is a test instrument that samples many digital lines simultaneously and displays them as parallel timing waveforms.…

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Logit Bias

Logit bias is a per-token override applied during decoding that nudges or forbids specific tokens regardless of what the model…

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Long Context Window

A long context window refers to a language model whose maximum input length stretches well beyond the few-thousand-token windows of…

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Longest Chain Rule

Intermediate

Nodes accept the chain with the most proof of work as the valid blockchain. Resolves competing chains.

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Lookahead Decoding

Lookahead decoding is a parallel decoding algorithm that accelerates language-model inference by breaking the strict left-to-right dependency of autoregressive generation.…

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LoRa

LoRa (Long Range) is a radio modulation technique developed by Semtech that enables long-distance wireless data transmission at very low…

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LoRA (Low-Rank Adaptation)

LoRA, short for Low-Rank Adaptation, is a parameter-efficient fine-tuning technique introduced by Hu et al. in 2021. Instead of updating…

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LoRA Alpha

LoRA alpha (often written lora_alpha) is the scaling hyperparameter that controls how strongly a LoRA adapter's low-rank update is applied…

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LoRA Rank

LoRA rank, written as r, is the central hyperparameter of Low-Rank Adaptation. It sets the inner dimension of the two…

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LoRaWAN

LoRaWAN is an open, royalty-free networking protocol standardised by the LoRa Alliance that sits on top of Semtech's LoRa radio…

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Loss Scaling

Loss scaling is a numerical technique that keeps low-precision training stable by preventing small gradients from vanishing to zero. In…

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Lost in the Middle

Lost in the middle is a documented failure pattern in which a language model retrieves and reasons over information most…

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Lottery Mining

Beginner

Solo mining with low odds but full block reward potential. The thrill of the possibility, every hash counts.

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Low-Dropout Regulator (LDO)

A low-dropout regulator (LDO) is a type of linear voltage regulator that can hold its output steady even when the…

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Luxor Mining Pool

Luxor Mining Pool is a Bitcoin mining pool operated by Luxor Technology, a U.S.-based company that also runs hashrate derivatives…

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M

MAC Address

A MAC (Media Access Control) address is a 48-bit identifier assigned to a network interface controller (NIC) and used to…

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Man-in-the-Middle Attack

A man-in-the-middle (MITM) attack is one in which an attacker secretly relays — and possibly alters — communications between two…

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Market Capitalization

Market capitalization, or "market cap," is the total market value of a cryptocurrency at a given moment. It is calculated…

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Mask Set

A mask set is the complete group of photomasks required to manufacture a particular chip. Each photomask, also called a…

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Masked Language Modeling

Masked language modeling (MLM) is a self-supervised pretraining task, popularized by BERT, in which some tokens of an input sentence…

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MAST (Merkelized Alternative Script Tree)

A Merkelized Alternative Script Tree, or MAST, is a way to lock bitcoin to many possible spending conditions while only…

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Master Weights

Master weights are a full-precision FP32 copy of a model's parameters maintained throughout low-precision training. In mixed-precision training, weights, activations,…

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Matryoshka Embedding

A Matryoshka embedding is a vector representation trained so that its leading dimensions already carry the most important information. Named…

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MCP (Model Context Protocol)

The Model Context Protocol (MCP) is an open standard, introduced by Anthropic in late 2024, for connecting AI applications to…

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Median Time Past (MTP)

Median Time Past, or MTP, is the timestamp Bitcoin uses to evaluate time-based timelocks. Instead of trusting a single block's…

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Medium of Exchange

A medium of exchange is one of the three classical functions of money, alongside unit of account and store of…

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Medusa Decoding

Medusa is an inference-acceleration framework that speeds up language-model generation by adding multiple lightweight prediction heads on top of the…

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Meek (Transport)

Meek is a pluggable transport that disguises censored but lawful traffic as ordinary HTTPS requests to a major, hard-to-block web…

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Megawatt (MW)

A megawatt (MW) is a unit of power equal to one million watts, or 1,000 kilowatts. It expresses the rate…

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Membership Inference Attack

A membership inference attack answers a single, privacy-sensitive question: was this exact data point part of the model's training set?…

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Memory Bandwidth

Memory bandwidth is the rate at which a processor can transfer data between its compute cores and its memory, measured…

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Memory Wall

The memory wall is the long-running phenomenon in which processor speed has improved far faster than memory bandwidth and latency,…

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Mempool

Intermediate

The waiting area for unconfirmed transactions. Miners pick transactions from here to include in blocks.

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Mempool Eviction

Mempool eviction is what a Bitcoin node does when its memory pool fills up: to stay within its configured size…

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Mempool Minimum Fee

The mempool minimum fee is the feerate floor a transaction must meet to be accepted into a particular node's memory…

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Mempool Persistence

Mempool persistence is the feature that lets a Bitcoin Core node remember its pool of unconfirmed transactions across a restart.…

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Mempool Policy

Mempool policy is the body of local, node-configurable rules that govern which unconfirmed transactions a Bitcoin Core node will accept…

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mempool.space (Self-Hosted Explorer)

mempool.space is an open-source block explorer and mempool visualizer maintained by The Mempool Open Source Project. It displays real-time and…

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Merged Mining (AuxPoW)

Merged mining lets a miner work on two or more separate blockchains simultaneously using a single proof-of-work computation. The technique,…

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Merkle Proof

A merkle proof, also called an inclusion proof or merkle branch, is the compact set of hashes that lets anyone…

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Merkle Root

Advanced

A hash summarizing all transactions in a block using a tree structure for efficient verification.

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Merkleize All The Things (MATT)

Merkleize All The Things, abbreviated MATT, is an experimental research approach for general smart contracts on Bitcoin, developed by Salvatore…

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Mesh Routing

Mesh routing is the set of techniques by which a network of peer radios relays each other's messages, so data…

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Mesh VPN (Overlay Network)

A mesh VPN is an overlay network in which devices form encrypted, peer-to-peer tunnels directly with one another instead of…

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Meshtastic

Meshtastic is an open-source project and firmware stack for LoRa radio hardware that turns commodity microcontroller boards into a peer-to-peer…

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Meta-Prompting

Meta-prompting is an advanced technique in which a language model is used to generate, refine, or analyse prompts — rather…

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Metadata

Metadata is data about data: the contextual details surrounding an activity rather than its content. For a phone call, the…

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Metadata-Resistant Messaging

Metadata-resistant messaging refers to communication systems engineered to conceal not just the contents of messages but the metadata surrounding them,…

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Metcalfe’s Law

Metcalfe's Law is a heuristic from network theory proposing that the value of a communications network grows in proportion to…

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Methane Mitigation

Methane mitigation refers to any approach that reduces the release of methane (CH₄) into the atmosphere. Methane is a short-lived…

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MiCA (Markets in Crypto-Assets)

MiCA, the Markets in Crypto-Assets Regulation (Regulation (EU) 2023/1114), is the European Union's comprehensive framework establishing uniform rules for crypto-assets…

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Microcontroller (MCU)

A microcontroller (MCU) is a single chip that packs a CPU core, a small amount of RAM and flash memory,…

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Microgrid

A microgrid is a local electrical network with clearly defined boundaries that behaves as a single, controllable entity. It bundles…

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Miner Capitulation

Miner capitulation is the point in a market cycle where a meaningful share of the Bitcoin mining sector becomes unprofitable…

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Miner Web UI

The miner web UI is the browser-based control panel that an ASIC miner serves from its own control board. You…

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Miner-Activated Soft Fork (MASF)

A Miner-Activated Soft Fork (MASF) is a backward-compatible protocol upgrade that switches on after a supermajority of miners signal their…

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Mining

Beginner

Using specialized hardware to validate Bitcoin transactions and earn block rewards by solving cryptographic puzzles.

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Mining as Business Income (Canada)

In Canada, the tax treatment of Bitcoin mining hinges on whether the Canada Revenue Agency (CRA) views the activity as…

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Mining Job (Stratum)

A mining job is the packet of work a pool sends to a connected miner over the Stratum protocol. Delivered…

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Mining Pool

Beginner

A group of miners who combine computing power and share block rewards proportionally.

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Mining Pool Decentralization

Mining pool decentralization refers to the goal of distributing control over Bitcoin block construction across many independent miners rather than…

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Mining Pool Fee

A mining pool fee is the cut a pool keeps from the rewards it distributes, charged in exchange for aggregating…

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Mining Profitability

Beginner

Net financial return from mining after subtracting electricity and other costs from Bitcoin earned.

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Mining Variance

Mining variance is the statistical randomness baked into proof-of-work. Because each hash is an independent lottery ticket with the same…

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Mining-as-a-Service (MaaS)

Mining-as-a-Service (MaaS) is a managed model in which a provider handles the operational side of Bitcoin mining — procurement, deployment,…

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Miniscript

Miniscript is a language for expressing a well-defined subset of Bitcoin Script in a structured way, designed so that scripts…

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minisign / signify

signify and minisign are deliberately minimal tools for signing files and verifying those signatures. signify was written for OpenBSD to…

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MIT License

The MIT License is one of the shortest and most widely adopted permissive licenses. It permits anyone to use, copy,…

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Mixnet (Mix Network)

A mixnet, or mix network, is a class of anonymity network designed to defeat traffic analysis, the practice of deducing…

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Mixture of Depths

Mixture of Depths (MoD) is a transformer technique, introduced by Google DeepMind, that spends compute unevenly across tokens. In a…

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Mixture of Experts (MoE)

Mixture of Experts (MoE) is a neural network architecture that splits a model's feed-forward layers into many specialized sub-networks called…

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Mixture of Tokens

Mixture of Tokens is a Transformer architecture, presented at NeurIPS 2024, designed as a more stable alternative to the sparse…

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MLC-LLM

MLC-LLM (Machine Learning Compilation for LLMs) is an open-source universal deployment engine for large language models. Its goal is to…

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MLOps

MLOps (Machine Learning Operations) is the set of practices, tooling, and culture that takes a trained machine learning model out…

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MMLU (Massive Multitask Language Understanding)

MMLU (Massive Multitask Language Understanding) is a benchmark introduced by Dan Hendrycks and colleagues in 2020 to measure how much…

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Modality Projector (Connector)

A modality projector, also called a connector, is the bridge component in a multimodal large language model (MLLM) that translates…

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Mode Collapse (LLM)

Mode collapse describes a failure in which a model converges on a narrow band of outputs, producing similar, stereotyped responses…

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Model Backdoor / Trojan

A model backdoor, also called a neural trojan, is a hidden malicious behavior planted in a machine learning model during…

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Model Card

A model card is a short, structured document that records the essential facts about a machine-learning model: what it is…

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Model Checkpoint

A model checkpoint is a saved snapshot of a model's state captured at a point during training. A complete checkpoint…

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Model Collapse

Model collapse is the progressive degradation that occurs when a generative model is trained, generation after generation, on data produced…

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Model Distillation

Model distillation, also called knowledge distillation, is a compression technique in which a small student model is trained to imitate…

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Model Extraction / Stealing

A model extraction attack, also called model stealing, recreates or closely approximates a proprietary machine learning model by repeatedly querying…

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Model FLOPs Utilization (MFU)

Model FLOPs Utilization (MFU) measures how efficiently an AI workload uses its hardware. It is the ratio of the useful…

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Model Inversion Attack

A model inversion attack attempts to reconstruct or infer the private features of the data a machine learning model was…

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Model Monitoring

Model monitoring is the continuous process of observing a deployed model's behavior and performance in production. A model that scored…

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Model Registry

A model registry is a centralized repository that stores trained machine learning models along with their metadata and manages each…

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Model Serving

Model serving is the infrastructure layer that takes a trained machine learning model and makes it answer prediction requests in…

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Modular Arithmetic

Modular arithmetic is a system in which numbers wrap around upon reaching a fixed value called the modulus, exactly the…

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Moore’s Law

Moore's Law is the observation, first made by Intel co-founder Gordon Moore in 1965, that the number of transistors that…

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MOSFET (Power Switching Transistor)

A MOSFET (metal-oxide-semiconductor field-effect transistor) is a voltage-controlled switch and the most common power-handling device on a mining ASIC's hashboard…

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MPC Wallet

An MPC wallet uses multi-party computation (MPC) to replace a single private key with distributed cryptographic control. Authority is divided…

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MT-Bench

MT-Bench is a benchmark introduced by Lianmin Zheng and colleagues in 2023 to evaluate a language model's conversational ability over…

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Mt. Gox

Mt. Gox was a Tokyo-based Bitcoin exchange that, at its peak around 2013, handled the large majority of global Bitcoin…

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Multi-Agent System

A multi-agent system coordinates two or more LLM-driven agents that each hold a role, a set of tools, and sometimes…

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Multi-Head Latent Attention (MLA)

Multi-Head Latent Attention (MLA) is an attention mechanism introduced in DeepSeek-V2 and carried into DeepSeek-V3 to attack the largest memory…

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Multi-Path Payments (MPP)

Multi-Path Payments (MPP) let a single Lightning payment be split into several smaller pieces, or "shards," that travel over different…

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Multi-Patterning

Multi-patterning is a family of fabrication techniques that print a single chip layer using more than one exposure or deposition…

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Multi-Query Attention (MQA)

Multi-Query Attention (MQA) is a modification of the standard multi-head attention used in transformer language models. In ordinary multi-head attention,…

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Multimeter

A multimeter is a handheld electronic instrument that measures multiple electrical quantities — DC and AC voltage, current, resistance, continuity,…

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Multimodal AI Model

A multimodal AI model is a machine-learning system capable of processing and integrating information from multiple modalities, or types of…

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Multimodal Alignment

Multimodal alignment is the process of mapping data from different modalities into a common representation space where semantically related items…

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Multimodal Model

A multimodal model is an AI system that can process and reason over more than one type of data, such…

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Multipath Payments (MPP)

Multipath Payments (MPP), specified in BOLT 4, let a Lightning node split a single payment into several smaller shards and…

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Multiphase Buck Converter

A multiphase buck converter is several buck (step-down) converter stages wired in parallel and switched out of phase with each…

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Multisig

Multisig, short for multi-signature, is a Bitcoin wallet arrangement that requires more than one key to authorize a spend. It…

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MuSig2 (BIP327)

MuSig2, standardized in BIP327 (merged March 2023), is a multi-signature scheme that lets several parties combine their public keys into…

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MVRV Ratio

The MVRV Ratio (Market Value to Realized Value) is an on-chain indicator defined as market capitalization divided by realized capitalization.…

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N

N-Gram Speculation

N-gram speculation, also called prompt lookup decoding, is the simplest form of speculative decoding for large language models. Where methods…

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n8n

n8n is a workflow automation platform built around a visual node editor: users connect nodes representing triggers, actions, and integrations…

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Nakamoto Consensus

Nakamoto Consensus is the consensus model introduced in the Bitcoin whitepaper, named after Bitcoin's pseudonymous creator. It lets a permissionless,…

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NAND Flash

NAND flash is a type of non-volatile solid-state memory used to store data that must survive a power cycle. On…

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NCCL

NCCL, the NVIDIA Collective Communications Library (pronounced "nickel"), provides the optimized routines that let multiple GPUs exchange and combine data…

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Need-to-Know Principle

The need-to-know principle holds that access to sensitive information should be granted only to those who genuinely require it to…

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Needle in a Haystack

The needle in a haystack test is a popular evaluation of a language model's long-context recall. A single out-of-place statement,…

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NEMA 14-50 Receptacle

The NEMA 14-50 is a high-capacity North American receptacle rated 125/250V at 50 amps, with four contacts: two hot conductors,…

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NEMA 5-15 Receptacle

The NEMA 5-15 is the ordinary grounded wall outlet found throughout North American homes and offices: 125 volts, 15 amps,…

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NEMA L6-30 Receptacle

The NEMA L6-30 is a locking (twist-lock) receptacle rated 250 volts and 30 amps, carrying two hot conductors and a…

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Nested SegWit (P2SH-P2WPKH)

Nested SegWit, formally P2SH-P2WPKH, embeds a native SegWit output inside a Pay-to-Script-Hash wrapper. The result is an address that begins…

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Network Address Translation (NAT)

Network Address Translation (NAT) is a technique routers use to map an entire private network onto a single public IP…

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Network Effect

A network effect (also called a network externality or demand-side economy of scale) occurs when the value a user derives…

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Network Hashrate

Beginner

The total computing power of all Bitcoin miners combined. Higher network hashrate means more competition.

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NF4 (4-bit NormalFloat)

NF4, or 4-bit NormalFloat, is a quantization data type introduced alongside the QLoRA fine-tuning method. It is designed around the…

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NIP (Nostr Implementation Possibility)

A NIP, or Nostr Implementation Possibility, is a specification document that describes how a particular feature of the Nostr protocol…

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NIP-05 (Nostr Identifier)

NIP-05 is the Nostr standard for tying a raw public key to a human-readable, DNS-backed identifier shaped like name@domain.com. A…

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NIP-07 (Browser Signer)

NIP-07 defines a standard window.nostr object that a browser extension injects into web pages, giving websites a controlled way to…

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NIP-17 (Private Direct Messages)

NIP-17 specifies private direct messages on Nostr that hide not just content but the surrounding metadata. It supersedes the old…

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NIP-44 (Versioned Encryption)

NIP-44 is the Nostr Improvement Proposal that defines versioned, keypair-based encryption for event payloads. It exists to replace the legacy…

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NIP-59 (Gift Wrap)

NIP-59 defines "gift wrapping," a three-layer construction that lets Nostr events hide not just their content but most of their…

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NixOS

NixOS is a free, open-source Linux distribution built on the Nix package manager and build system. Its defining idea is…

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NNCP (Node to Node Copy)

NNCP (Node to Node Copy) is a collection of utilities for secure, store-and-forward exchange of files, mail, and commands between…

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No-Clean Flux

No-clean flux is a soldering flux formulated to leave a small, chemically benign residue that can safely remain on the…

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No-Coiner

"No-coiner" is Bitcoin community slang for a person who holds no bitcoin and is generally skeptical or dismissive of it.…

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Noctua Fan

Beginner

Premium quiet fans used to replace loud stock miner fans, making home mining feasible.

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Noise Level (dB)

Beginner

Miner sound output in decibels. Stock ASICs are 75-85 dB but can be reduced to under 40 dB for home…

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Noise Protocol Handshake (Stratum V2)

Every Stratum V2 connection is encrypted and authenticated by a handshake built on the Noise Protocol Framework. This is one…

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Noise Reduction

Beginner

Techniques to quiet mining hardware for home use: fan swaps, enclosures, immersion, and acoustic insulation.

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Nominal vs. Actual Hashrate

Every ASIC ships with a nominal hashrate — the manufacturer's nameplate figure, usually quoted with a tolerance band such as…

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Nonce

Intermediate

A number miners change to produce different hash results when searching for a valid block.

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Nonce Reuse

Nonce reuse is one of the most dangerous failure modes in digital signatures, including the ECDSA and Schnorr schemes Bitcoin…

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Nonce Space

Nonce space - sometimes called the search space - is the full set of header values a miner is free…

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Nostr

Nostr — short for "Notes and Other Stuff Transmitted by Relays" — is an open protocol for decentralized social networking…

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Nostr Event Kind

An event kind is the integer field, defined in NIP-01, that every Nostr event carries to declare what it is.…

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Nostr Marketplace (NIP-15)

NIP-15 defines a decentralized marketplace built directly on Nostr, letting a merchant run a storefront with nothing but a keypair…

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Nostr Outbox Model (Gossip)

The Outbox Model, historically called the "gossip" model, is a relay-routing strategy defined by NIP-65 that keeps Nostr decentralized as…

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Nostr Relay

A Nostr relay is a simple server that accepts, stores, and forwards the cryptographically signed messages that make up the…

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Nostr Wallet Connect (NIP-47)

Nostr Wallet Connect (NWC), defined in NIP-47, is a protocol that lets a Nostr or Lightning application send commands to…

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Nostr Zap (NIP-57)

A Nostr Zap is a Lightning Network tip sent in response to a Nostr profile or note, standardized in NIP-57.…

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Notification Transaction

A notification transaction is the handshake that bootstraps a BIP47 payment-code relationship. Before a sender can derive private one-time addresses…

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NPU (Neural Processing Unit)

A Neural Processing Unit (NPU) is a class of hardware accelerator designed to speed up artificial-intelligence and machine-learning workloads, especially…

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npub / nsec

npub and nsec are the two halves of a Nostr identity, encoded in a human-friendly format defined by NIP-19. The…

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Nuclear-Powered Mining (SMR)

Nuclear-powered mining sources electricity for ASIC fleets, or for co-located compute and data-center loads, from nuclear generation. Interest has grown…

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NVLink

NVLink is NVIDIA's proprietary high-speed interconnect for direct GPU-to-GPU communication. When a model is too large to fit on a…

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NVT Ratio

The NVT Ratio (Network Value to Transactions) is an on-chain valuation metric that divides a network's market capitalization by the…

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O

obfs4

obfs4 (the "obfourscator") is a randomizing pluggable transport that wraps a connection in a layer of specialized encryption so that…

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OCEAN (Mining Pool)

OCEAN is a Bitcoin mining pool that launched in 2023, co-founded by Bitcoin Core developer Luke Dashjr and backed by…

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Off-Grid Compute

Off-Grid Compute is the operation of computing workloads — Bitcoin mining, AI inference, data processing, or mesh communications — from…

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Off-Grid Mining

Off-grid mining describes any Bitcoin mining operation that draws power from a dedicated, privately controlled source rather than from the…

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Oil-Filled Transformer

An oil-filled (liquid-immersed) transformer submerges its windings and core in insulating mineral oil or ester fluid, which acts simultaneously as…

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Okapi BM25

Okapi BM25 ("Best Matching 25") is a probabilistic ranking function that scores how relevant a document is to a keyword…

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Ollama

Ollama is an open-source platform for running large language models locally with a single command. Written mainly in Go and…

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On-Load Tap Changer (OLTC)

An on-load tap changer (OLTC) is a switching device built into a power transformer that adjusts the transformer's turns ratio…

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On-Premise AI

On-Premise AI is AI inference and, where applicable, training infrastructure deployed within a physical facility owned or leased by the…

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One-Shot Prompting

One-shot prompting provides a language model with exactly one worked example inside the prompt before asking it to handle the…

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Onion Service (.onion)

An onion service (historically a "hidden service") is a server — a website, a Bitcoin node, an SSH endpoint —…

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Online DPO

Online DPO is a variant of Direct Preference Optimization in which the preference pairs used for training are generated on-policy…

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ONNX

ONNX (Open Neural Network Exchange) is a community-driven open standard for representing machine-learning models in a portable way. It defines…

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Ontology

An ontology is a formal, explicit specification of the concepts in a domain and the relationships that can hold between…

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Opcode

An opcode (operation code) is a single-byte instruction in Bitcoin Script. Each opcode tells the script interpreter to perform one…

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Open Cycle Gas Turbine (OCGT / Peaker)

An Open Cycle Gas Turbine (OCGT), also called a simple-cycle or peaker turbine, is the most basic form of gas-fired…

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Open-Source Firmware

Intermediate

Publicly available mining firmware that can be audited, modified, and improved by the community.

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Open-Source Mining

Beginner

Mining hardware with publicly available designs. Anyone can build, modify, and improve the hardware.

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Open-Weight Model

An open-weight model is one whose trained parameters, the numeric weights that constitute the model, are published for anyone to…

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Operational Amplifier (Op-Amp)

An operational amplifier, or op-amp, is a high-gain DC amplifier with two inputs: a non-inverting input (+) and an inverting…

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Operational Intensity

Operational intensity is the metric used as the horizontal axis of the roofline model: the number of operations performed per…

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Operational Security (OPSEC)

Operational security, almost always shortened to OPSEC, is a systematic process for denying an adversary the information they would need…

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OPSEC (Operational Security)

OPSEC — operational security — is the discipline of protecting yourself by controlling the small pieces of information that, taken…

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Optical Character Recognition (OCR)

Optical Character Recognition (OCR) is the conversion of images of text, from scanned documents, photographs, or screenshots, into machine-encoded characters…

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Optimizer State

Optimizer state is the per-parameter bookkeeping an adaptive optimizer keeps between update steps. The Adam optimizer and its variants, the…

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OP_CAT

OP_CAT is a Bitcoin Script opcode that takes the top two items on the stack, joins them into a single…

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OP_CHECKCONTRACTVERIFY (CCV)

OP_CHECKCONTRACTVERIFY (often abbreviated CCV) is a proposed, experimental Bitcoin opcode authored by Salvatore Ingala and published as BIP 443. It…

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OP_CHECKLOCKTIMEVERIFY (CLTV)

OP_CHECKLOCKTIMEVERIFY, abbreviated CLTV, is a Bitcoin Script opcode introduced in BIP 65 that lets a locking script enforce an absolute…

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OP_CHECKMULTISIG

OP_CHECKMULTISIG (opcode 0xae) implements classic m-of-n multisignature validation in legacy Bitcoin Script. It reads a public-key count n and n…

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OP_CHECKSEQUENCEVERIFY (CSV)

OP_CHECKSEQUENCEVERIFY, abbreviated CSV, is a Bitcoin Script opcode defined in BIP 112 that enforces a relative timelock. Rather than a…

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OP_CHECKSIG

OP_CHECKSIG (opcode 0xac) is the workhorse signature-verification operation in Bitcoin Script. It pops two items from the stack — a…

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OP_CHECKSIGADD

OP_CHECKSIGADD (opcode 0xba) is the Tapscript replacement for legacy multisignature, introduced in BIP 342 alongside the Taproot upgrade. It pops…

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OP_CHECKSIGFROMSTACK (CSFS)

OP_CHECKSIGFROMSTACK, abbreviated CSFS, is a proposed Bitcoin opcode described in BIP 348, with authorship credited to Brandon Black and Jeremy…

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OP_CHECKTEMPLATEVERIFY (CTV)

OP_CHECKTEMPLATEVERIFY (CTV), specified in BIP 119 by Jeremy Rubin, is a proposed Bitcoin opcode that commits an output to a…

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OP_CHECKTEMPLATEVERIFY (CTV)

OP_CHECKTEMPLATEVERIFY, abbreviated CTV and specified in BIP119, is a proposed Bitcoin opcode that lets an output commit, in advance, to…

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OP_HASH160

OP_HASH160 (opcode 0xa9) consumes the top item on the stack, computes RIPEMD160(SHA256(x)) of that item, and pushes the resulting 20-byte…

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OP_IF / Script Conditional

OP_IF and its companions OP_NOTIF, OP_ELSE, and OP_ENDIF are the conditional flow-control opcodes of Bitcoin Script. They let a single…

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OP_RETURN

OP_RETURN is a Bitcoin Script opcode that immediately marks the script it appears in as invalid, making any output that…

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OP_SUCCESS (Tapscript)

OP_SUCCESS opcodes are Tapscript's built-in upgrade hooks, defined in BIP 342 as part of the Taproot soft fork. A range…

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OP_TXHASH

OP_TXHASH is a proposed, experimental Bitcoin opcode described in BIP 346, authored by Steven Roose and Brandon Black. It is…

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OP_VAULT

OP_VAULT is a proposed covenant opcode described in BIP 345 by James O'Beirne (later co-authored with Greg Sanders). It is…

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Oracle Announcement

An oracle announcement is the message an oracle publishes before an event occurs, committing in advance to sign its eventual…

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Oracle Attestation

An oracle attestation is the cryptographic signature an oracle publishes after a real-world event resolves, declaring which outcome actually occurred.…

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Orange Pill

The "orange pill" is a metaphor in Bitcoin culture for the moment a person begins to understand and accept Bitcoin's…

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Ordinals

Ordinals is a numbering scheme, introduced by Casey Rodarmor in January 2023, that assigns every satoshi a unique serial number…

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Orphan Block

Intermediate

A valid block rejected by the network because a competing block at the same height was accepted first.

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ORPO (Odds Ratio Preference Optimization)

ORPO (Odds Ratio Preference Optimization) is a preference-alignment method that merges supervised fine-tuning and preference learning into one step, removing…

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Outbound Connection Slots

Outbound connection slots are the peer links a Bitcoin Core node initiates itself, as opposed to inbound connections it merely…

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Output Descriptor

An output descriptor is a compact, machine-readable string that fully and unambiguously describes how a set of Bitcoin outputs can…

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Output Linking

Output linking is the process by which blockchain analysts connect the outputs of one transaction to the inputs of later…

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Output Linking Resistance

Output linking resistance is the property that lets a recipient accept many payments to one logical identity while a public…

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Output Registration

Output registration is the CoinJoin phase in which each participant tells the coordinator which outputs they want the final transaction…

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Overclocking

Intermediate

Running mining hardware faster than default to increase hashrate, at the cost of more power and heat.

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Overfitting

Overfitting describes a model that has learned its training data too well, capturing not just the underlying patterns but also…

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P

P-Tuning

P-tuning is a parameter-efficient fine-tuning method that adapts a frozen language model by learning continuous prompt embeddings, but it differs…

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P2PKH (Legacy Address)

P2PKH (Pay to Public Key Hash) is Bitcoin's original standard address type, the default wallets used from 2009 until SegWit…

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P2TR (Pay to Taproot)

P2TR (Pay to Taproot) is the output type activated by the 2021 Taproot soft fork. It is witness version 1,…

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P2WPKH (Native SegWit)

P2WPKH (Pay to Witness Public Key Hash) is the native Segregated Witness equivalent of a legacy P2PKH output, introduced with…

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Package Relay (BIP-331)

Package relay is a proposed enhancement to Bitcoin's peer-to-peer transaction relay, formalized as BIP-331, that lets nodes announce and evaluate…

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Packet Radio

Packet radio is a mode of sending digital data over amateur (ham) radio frequencies, packaging information into discrete frames that…

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Parameter Count

The parameter count of a machine-learning model is the total number of trainable weights it contains — the individual numbers,…

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Parrot OS

Parrot OS (Parrot Security) is a free, open-source, Debian-based Linux distribution oriented toward cybersecurity operations, privacy, and software development. It…

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Passphrase (25th Word)

A BIP39 passphrase, often called the 25th word, is an optional secret you supply alongside your written seed phrase. Unlike…

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Pay-to-Contract

Pay-to-contract is the cryptographic construction that lets a party embed an arbitrary commitment inside an ordinary-looking public key without changing…

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Pay-to-EndPoint (P2EP)

Pay-to-EndPoint (P2EP) is the conceptual ancestor of PayJoin. It describes a payment in which the receiver contributes one or more…

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Pay-to-Script-Hash (P2SH)

Pay-to-Script-Hash, or P2SH, is a Bitcoin output type defined in BIP 16 that locks coins to the hash of a…

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PayJoin (P2EP)

PayJoin — also called Pay-to-EndPoint (P2EP) and standardized in BIP-78 — is a collaborative payment in which both the sender…

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Payment Channel

A payment channel is the foundational building block of the Lightning Network. Two parties open a channel by broadcasting a…

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Payment Code (BIP47)

A payment code is the static identifier at the heart of BIP47, "Reusable Payment Codes for Hierarchical Deterministic Wallets." Technically…

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PayNym

A PayNym is a memorable, shareable handle layered on top of a BIP47 payment code. Because a raw payment code…

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PCB

Intermediate

The circuit board that supports and connects mining chips. The physical foundation of a hashboard.

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PCB Delamination

Delamination is the separation of the bonded layers inside a printed circuit board, either between copper and laminate or between…

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PCB Stackup

A PCB stackup is the layer-by-layer arrangement of copper foils and insulating dielectric materials that make up a multilayer printed…

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PCB Trace

A PCB trace is a flat copper conductor etched onto a printed circuit board that carries current or signal from…

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PCI Express (PCIe)

PCI Express (PCIe) is the high-speed expansion bus that modern computers use to connect add-in cards such as graphics cards,…

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PDU

Intermediate

A power distribution device for feeding multiple miners from one circuit with monitoring and protection.

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Peak Shaving

Peak shaving is the practice of reducing a facility's highest instantaneous power demand during periods when electricity is most expensive…

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Peaker Plant

A peaker plant, or "peaker," is a power station that runs only during periods of peak electricity demand, the hot…

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Peer Eviction Logic

Peer eviction logic is the routine inside Bitcoin Core, implemented as AttemptToEvictConnection(), that decides which existing inbound peer to drop…

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PEFT (Parameter-Efficient Fine-Tuning)

Parameter-Efficient Fine-Tuning (PEFT) is an umbrella term for techniques that specialise a large language model to a new task or…

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Peg-In

A peg-in is the act of moving bitcoin from the main chain onto a federated Bitcoin sidechain such as Liquid,…

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Peg-Out

A peg-out is the reverse of a peg-in: a participant burns Liquid Bitcoin (L-BTC) on the sidechain and receives an…

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Permissionless

Permissionless describes a system that anyone may join and use without seeking approval from a central authority. On the Bitcoin…

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Permissive License

A permissive license is a class of open-source license that grants broad rights to use, modify, and redistribute software while…

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Perplexity (Metric)

Perplexity is one of the oldest and most fundamental metrics for evaluating language models. It measures how well a model…

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Petahash, Exahash, and Zettahash

As Bitcoin's computing power grew beyond what a single machine produces, larger SI-prefixed units became necessary to describe aggregated hashrate.…

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PGP / GPG

PGP (Pretty Good Privacy) is the original public-key encryption and signing program created by Phil Zimmermann in 1991. GPG (GNU…

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Phase-Locked Loop (PLL)

A phase-locked loop (PLL) is a feedback control circuit that produces an output clock whose phase and frequency are locked…

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PHIPA

The Personal Health Information Protection Act, 2004 (PHIPA) is Ontario's provincial health privacy law, cited as S.O. 2004, Chapter 3,…

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Phoenix Wallet

Phoenix is a self-custodial mobile Bitcoin wallet built by ACINQ that uses the Lightning Network to send and receive payments.…

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Photolithography

Photolithography is the core patterning technique used to build integrated circuits. It works much like photographic printing: a light-sensitive chemical…

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PIC Microcontroller (Antminer)

The PIC microcontroller is a small Microchip chip (commonly a PIC16F-series part) found on many conventional Antminer hashboards. Its job…

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PIPEDA

The Personal Information Protection and Electronic Documents Act (PIPEDA) is Canada's federal private-sector privacy law. It sets the ground rules…

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Pipeline Parallelism

Pipeline parallelism, also called vertical or inter-layer parallelism, splits a model by depth. The layers are divided into consecutive stages,…

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Planar Transistor

A planar transistor is the traditional, flat MOSFET in which the source, gate, and drain all sit on a single…

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Planner-Executor Pattern

The planner-executor pattern, also called plan-then-execute, is an agentic design that separates reasoning from action. A planner component first formulates…

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Plausible Deniability

Plausible deniability is a security property that lets you credibly deny the existence of hidden data or assets, even when…

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Plenum

A plenum is a sealed, pressurized air space used to distribute or collect air across a cooling system. In data…

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Pluggable Transport

A pluggable transport (PT) is a modular software component that reshapes the data flow between a client and an entry…

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Point Time-Locked Contract (PTLC)

A Point Time-Locked Contract (PTLC) is a conditional Lightning Network payment that locks funds to a point on Bitcoin's elliptic…

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Policy Gradient

Policy gradient is a family of reinforcement-learning methods that optimize a model's behavior, its policy, directly by following the gradient…

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Policy vs Consensus Rules

Bitcoin enforces two distinct layers of rules, and conflating them is a common source of confusion. Consensus rules determine whether…

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Polynomial Commitment Scheme

A polynomial commitment scheme lets a prover publish a short commitment to a polynomial, then later prove the polynomial's value…

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Pool Fee

Beginner

The percentage a pool takes from rewards. Ranges from 0-4% depending on the pool and payout method.

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Pool Hopping

Pool hopping is a strategy in which a miner directs hashrate to a pool only when each submitted share is…

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Pool Luck

Pool luck is a metric that compares how many shares a pool was statistically expected to submit before finding a…

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Port Forwarding

Port forwarding is a router configuration that tells your network to deliver unsolicited inbound traffic arriving on a particular port…

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Position Interpolation

Position interpolation extends the usable context length of a model built on rotary position embeddings by squeezing longer position indices…

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Positional Encoding (RoPE)

Self-attention treats a sequence as an unordered set, so a Transformer needs an explicit signal telling it where each token…

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Post-Mix Spending

Post-mix spending is the discipline of using coins after a CoinJoin without undoing the privacy you just gained. A mix…

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Power Circuit

Beginner

The electrical wiring and breaker serving mining hardware. Full-size miners often need dedicated 240V circuits.

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Power Distribution Unit (PDU)

A power distribution unit (PDU) takes one high-capacity electrical feed and divides it into many protected outlets, letting a single…

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Power Factor

Power factor (PF) is the ratio of real power, measured in kilowatts (kW), to apparent power, measured in kilovolt-amperes (kVA),…

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Power Factor Correction (PFC)

Power Factor Correction (PFC) is the front-end circuitry inside a switch-mode power supply that forces the current drawn from the…

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Power Gating

Power gating is a low-power technique that completely cuts the supply voltage to a region of a chip when it…

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Power Plane

A power plane is a continuous copper layer in a PCB stackup dedicated to carrying one supply voltage, such as…

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Power Purchase Agreement (PPA)

A Power Purchase Agreement (PPA) is a long-term contract between an electricity generator (or independent power producer) and a buyer,…

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Power Quality

Power quality describes how closely the electricity delivered to a load matches an ideal, undistorted sine wave at the correct…

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Power Usage Effectiveness (PUE)

Power Usage Effectiveness (PUE) is the ratio of the total energy a facility draws from the grid to the energy…

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Power Whip

A power whip (also called a PDU whip) is a heavy-duty, pre-assembled cable that brings power from a remote power…

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PPLNS

Intermediate

A pool payout distributing actual block rewards based on shares contributed. Lower fees but more variable income.

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PPO (Proximal Policy Optimization)

Proximal Policy Optimization (PPO) is a policy-gradient reinforcement-learning algorithm introduced by OpenAI in 2017. It became the standard optimizer for…

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PPS

Intermediate

A pool payout paying a fixed rate per share based on the block subsidy only, not transaction fees.

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Preference Dataset

A preference dataset is the fuel for modern LLM alignment: a collection of prompts where, for each one, responses are…

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Prefill Phase

The prefill phase is the first of two stages in large language model (LLM) inference. When you send a prompt,…

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Prefill-Decode Disaggregation

Prefill-decode disaggregation is a serving architecture that runs the two phases of language-model inference on physically separate hardware. The prefill…

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Prefix Caching

Prefix caching is an inference optimization that reuses computation across separate requests whenever they begin with the same tokens. Many…

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Prefix Tuning

Prefix tuning is a parameter-efficient fine-tuning method that steers a frozen language model by prepending a sequence of trainable continuous…

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Preheater

A preheater is a bench rework tool that brings an entire circuit board up to an elevated baseline temperature before…

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Pretraining

Pretraining is the first and most computationally expensive stage of building a large language model. The model is trained on…

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Prime vs Standby Power Rating

Under ISO 8528, a generator set carries different power ratings depending on how it will be used, and choosing the…

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Principle of Least Privilege

The principle of least privilege (PoLP) holds that any user, account, process, or device should have only the minimum access…

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Printed Circuit Board (PCB)

A printed circuit board (PCB) is the rigid board, usually fiberglass (FR-4), with etched copper traces that both physically mount…

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Probabilistic Finality

Probabilistic finality describes how Bitcoin settles transactions: there is no single moment at which a payment becomes officially irreversible. Instead,…

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Process Node

A process node is the name given to a particular generation of semiconductor manufacturing technology, expressed in nanometers, for example…

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Product Quantization

Product quantization (PQ) is a vector-compression technique for approximate nearest-neighbour search, introduced by Jegou, Douze, and Schmid in 2011. Instead…

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Profit Switching

Profit switching is the practice of automatically pointing your hashrate at whichever coin — or whichever algorithm — currently yields…

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Prompt Caching

Prompt caching lets an inference engine store a frequently reused prompt prefix (system instructions, tool definitions, long documents, or examples)…

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Prompt Compression

Prompt compression shortens the text fed to a language model by deleting or condensing tokens that contribute little information, cutting…

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Prompt Engineering

Prompt engineering is the deliberate design of the inputs given to a language model so that it produces accurate, relevant,…

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Prompt Injection

Prompt injection is the top-ranked vulnerability (LLM01) in the OWASP Top 10 for Large Language Model Applications. It occurs when…

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Prompt Template

A prompt template is a reusable prompt skeleton that combines fixed text — instructions, role context, formatting rules — with…

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Prompt Tuning

Prompt tuning is one of the simplest parameter-efficient fine-tuning methods: it freezes the entire pretrained model and learns only a…

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Proof of Authority

Proof of Authority (PoA) is a consensus mechanism used mainly in permissioned blockchains, where a small set of pre-approved, publicly…

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Proof of Burn

Proof of Burn (PoB) is a mechanism in which participants permanently destroy cryptocurrency to earn the right to validate blocks…

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Proof of Keys

Proof of Keys is an annual Bitcoin tradition in which participants withdraw their bitcoin from third-party custodians, such as exchanges,…

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Proof of Reserves

Proof of Reserves (PoR) is a verification practice in which a custodial platform demonstrates that it actually holds enough assets…

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Proof of Space

Proof of Space (PoSpace), sometimes called proof of capacity, is a consensus mechanism in which participants demonstrate they have reserved…

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Proof of Stake

Proof of Stake (PoS) is a consensus mechanism in which the right to validate transactions and produce blocks is allocated…

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Proof of Work

Beginner

Bitcoin's security mechanism requiring miners to expend energy to validate transactions and create blocks.

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Propagation Delay

Advanced

The time for a new block to spread across the network. Faster propagation reduces competing blocks.

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Protection Relay

A protection relay is the decision-making element of an electrical protection scheme. It continuously watches measured quantities, current, voltage, frequency,…

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Pruned Node

A pruned node is a Bitcoin full node that fully validates every block during the initial download but then deletes…

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PSBT (Partially Signed Bitcoin Transaction)

A Partially Signed Bitcoin Transaction, or PSBT, is a standardized container format defined in BIP174 for moving a transaction between…

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Pseudonymity

Pseudonymity is the near-anonymous state in which you operate under a consistent identifier, a pseudonym, that is not your legal…

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PSU

Beginner

The power supply that converts AC electricity to DC power for the miner. A critical component affecting efficiency.

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Public Pool

Beginner

A no-fee, no-registration solo mining pool popular with Bitaxe users. Full block reward goes to the finder.

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Pump-Out Effect

The pump-out effect is the progressive displacement of thermal paste from between a chip and its heatsink, driven by repeated…

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Purchasing Power

Purchasing power is the real value of money expressed as the quantity of goods and services one unit can actually…

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R

Race Attack

A race attack is the simplest form of double-spend against a merchant who accepts zero-confirmation payments. The attacker creates two…

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Radio Duty Cycle

The radio duty cycle is the proportion of time a transmitter is allowed to be actively sending on a given…

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RAG (Retrieval-Augmented Generation)

Retrieval-augmented generation (RAG) is a technique that lets a large language model pull in relevant, up-to-date information from an external…

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Ramp Rate

Ramp rate is the speed at which a power source — or a controllable load — can change its output,…

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RaspiBlitz

RaspiBlitz is an open-source project, released under the MIT license, that lets a user build and operate a Bitcoin and…

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Rate of Change of Frequency

Rate of Change of Frequency (RoCoF) measures how quickly an AC grid's frequency moves immediately after a generation-load imbalance, expressed…

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Re-Ranking Cross-Encoder

A re-ranking cross-encoder is the precision stage of a two-stage retrieval pipeline. Where a first-stage retriever quickly fetches a broad…

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ReAct Pattern

ReAct, short for Reasoning and Acting, is a prompting paradigm introduced in the 2022 paper ReAct: Synergizing Reasoning and Acting…

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Realized Cap

Realized Cap (realized capitalization) is an on-chain valuation model that values each unit of bitcoin at the price it last…

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Realized Price

Realized Price is an on-chain valuation figure equal to the Realized Cap divided by the circulating supply. Conceptually, it expresses…

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Rear-Door Heat Exchanger (RDHx)

A Rear-Door Heat Exchanger (RDHx) is a cooling coil built into the back door of a server or miner rack.…

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Reasoning Model

A reasoning model, sometimes called a large reasoning model (LRM) or reasoning language model, is a language model specifically trained…

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Reballing

Reballing is the process of restoring a fresh, uniform set of solder balls to the underside of a BGA chip…

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Reciprocal Rank Fusion (RRF)

Reciprocal Rank Fusion (RRF) is a lightweight algorithm for merging two or more ranked result lists into a single combined…

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Reciprocating Engine Genset

A reciprocating engine genset pairs a large internal-combustion piston engine, typically a four-stroke, spark-ignited, lean-burn gas unit, with an alternator…

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Rectifier

A rectifier is a device that converts alternating current (AC) into direct current (DC). It is the electrical inverse of…

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Recurrent Neural Network (RNN)

A Recurrent Neural Network (RNN) is a class of neural network designed for sequential data, where connections loop back on…

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Recursive Covenant

A recursive covenant is a covenant whose restrictions reproduce themselves in the outputs it creates, so the same rules can…

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Red-Teaming (AI)

Red-teaming in AI is the practice of deliberately attacking a model with adversarial inputs to uncover security vulnerabilities, safety failures,…

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Redistribution Layer (RDL)

A redistribution layer, or RDL, is one or more layers of patterned copper traces and dielectric film built directly onto…

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Redundancy Repair

Redundancy repair is the technique foundries use to salvage chips that contain a small number of manufacturing defects. Rather than…

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Reflexion (Verbal Reinforcement Learning)

Reflexion is a framework for improving language agents without retraining their weights. Instead of gradient updates, the agent receives a…

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Reflow

Reflow is the controlled melting and re-solidifying of solder used to attach or reseat chips during hashboard repair. Rather than…

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Reflow Oven

A reflow oven is a multi-zone heating chamber used in surface-mount assembly and board-level repair to melt solder paste and…

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Reflow Profile

A reflow profile is the controlled temperature-versus-time curve a board (or a localized work area) is taken through when melting…

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Reflowing

Advanced

Reheating solder joints to fix broken connections. A common repair for intermittent chip failures.

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Refurbished ASIC

A refurbished ASIC is a previously owned Bitcoin miner that a repair shop has tested, repaired where necessary, and verified…

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Regtest

Regtest (regression test mode) lets a developer run a completely private Bitcoin blockchain with the same basic rules as testnet,…

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Regularization

Regularization is a collective name for techniques that deliberately constrain a model during training so it generalizes better to unseen…

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Reindex

Reindexing is Bitcoin Core's recovery and rebuild operation. Launching with -reindex wipes the block index and the chainstate (UTXO) databases,…

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Reissuance Token

A reissuance token is a control asset created alongside a newly issued token on a Bitcoin sidechain like Liquid. Its…

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Reject Rate

The reject rate is the fraction of shares a mining pool refuses to credit, expressed as a percentage of all…

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Rejection Sampling Fine-Tuning

Rejection Sampling Fine-Tuning is an alignment technique where the model generates several candidate responses for each prompt, a reward model…

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Relative Timelock

A relative timelock prevents a coin from being spent until a defined amount of time has elapsed since the output…

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Renewable Energy Certificate (REC)

A Renewable Energy Certificate (REC) is a market-based instrument that represents the legal property rights to the environmental and non-power…

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Reorg Protection

Reorg protection refers to the practices that guard a recipient against a chain reorganization quietly undoing a transaction they believed…

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Repetition Penalty

Repetition penalty is a decoding control that discourages a language model from repeating tokens it has already produced or seen…

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Replace-By-Fee (RBF)

Replace-By-Fee, or RBF, is a node mempool policy that allows an unconfirmed transaction to be swapped out for a new…

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Replay Attack

A replay attack in the blockchain context occurs when a transaction that is valid on one chain is maliciously rebroadcast…

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Replay Protection

Replay protection is a safeguard added during a chain split that ensures a transaction can be confirmed on only one…

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Reproducible Builds

Reproducible builds (also called deterministic builds) are software build processes in which, given identical source code and a fully specified…

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Reproducible Builds (Bitcoin)

Reproducible builds are a technique that lets multiple independent people compile the same source code into byte-for-byte identical binaries. For…

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Request Scheduling (LLM Serving)

Request scheduling is the logic inside a large language model inference server that decides, at each step, which queued requests…

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Reranking

Reranking is a precision step in retrieval pipelines that re-orders an initial set of candidate documents by how relevant each…

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Residential Mining

Beginner

Mining in a home setting, balancing hashrate with noise, heat, and power constraints of residential life.

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Residual Connection

A residual connection, also called a skip connection, is a shortcut that adds a layer's input directly to its output…

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Resistor

A resistor is a passive two-terminal component whose only job is to oppose the flow of electric current. That opposition,…

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Reticulum

Reticulum is an open-source cryptographic networking stack designed to build resilient, operator-independent networks over almost any medium — LoRa radios,…

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Retrieval Evaluation Metrics

Retrieval evaluation metrics quantify how well a search or retrieval system surfaces the right documents for a query. They are…

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Reusable Payment Address

A reusable payment address is a static identifier you can publish once — on a profile, a donation page, or…

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Reverse Proxy

A reverse proxy is a server that sits in front of one or more backend applications and forwards client requests…

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Reward Hacking

Reward hacking, also called specification gaming, occurs when a system trained with reinforcement learning finds a way to maximize its…

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Reward Model

A reward model is a neural network that takes a prompt and a candidate response and outputs a single scalar…

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Reward Shaping

Reward shaping is a reinforcement-learning technique that supplements an environment's sparse or delayed reward with extra intermediate signals, helping a…

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RGB Protocol

RGB is a smart-contract and asset-issuance system for Bitcoin and the Lightning Network developed under the LNP/BP Standards Association. Rather…

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Ride The Lightning (RTL)

Ride The Lightning (RTL) is a web-based, device-agnostic interface for managing Lightning Network node operations from a browser. Rather than…

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Right to Repair

Right to repair is the principle — increasingly backed by law — that the person who owns a device should…

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Ring Oscillator

A ring oscillator is one of the simplest yet most revealing structures on a chip: an odd number of inverters…

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Ring Signature

A ring signature is a type of digital signature that can be produced by any member of a defined group…

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RLAIF (Reinforcement Learning from AI Feedback)

Reinforcement Learning from AI Feedback (RLAIF) is an alignment technique in which the preference judgments that steer a model's training…

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RLHF (Reinforcement Learning from Human Feedback)

RLHF (Reinforcement Learning from Human Feedback) is the alignment technique that turned raw language models into helpful assistants. Introduced at…

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RMA (Return Merchandise Authorization)

RMA, short for Return Merchandise Authorization, is the formal process by which a buyer returns a product — here, a…

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ROCm

ROCm (Radeon Open Compute) is AMD's open-source software platform for GPU-accelerated computing. It is AMD's answer to NVIDIA's CUDA ecosystem,…

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ROI

Beginner

The time for mining profits to pay back the hardware cost. Shorter payback periods are better.

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Rollout (Reinforcement Learning)

In reinforcement learning, a rollout is a complete trajectory the model generates by acting out its current policy from a…

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Roofline Model

The roofline model is a simple, visual performance model that bounds the maximum throughput a workload can achieve on a…

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Rootstock (RSK)

Rootstock (RSK) is a long-running Bitcoin sidechain that adds a smart-contract platform compatible with the Ethereum Virtual Machine (EVM). It…

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Rotary Position Embedding (RoPE)

Rotary Position Embedding (RoPE) is the technique most modern open-weight language models use to tell the attention mechanism where each…

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Round-Amount Heuristic

The round-amount heuristic is a change-detection shortcut used in blockchain analysis. People tend to send payments in tidy figures, 0.05…

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Routing Node

A routing node is a Lightning Network node that forwards payments on behalf of others, earning fees for the liquidity…

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RSSI (Received Signal Strength Indicator)

RSSI, the Received Signal Strength Indicator, is the absolute power a radio receiver measures at its antenna input, expressed in…

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Runes

Runes is a protocol for issuing fungible tokens on Bitcoin, designed by Ordinals creator Casey Rodarmor and launched at the…

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RWKV

RWKV (Receptance Weighted Key Value, pronounced "RwaKuv") is a sequence-modeling architecture that combines the parallelizable training of transformers with the…

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S

SAC305 Solder Alloy

SAC305 is the most widely used lead-free solder alloy in modern electronics, and the one you will most often encounter…

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Satoshi (unit)

A satoshi, often shortened to "sat," is the smallest unit of bitcoin recorded on the blockchain. One satoshi equals 0.00000001…

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Sats per Terahash

Intermediate

Mining revenue measured in satoshis per terahash per day. Shows BTC yield independent of price.

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Sats per vByte

Sats per vByte (sat/vB) is the standard way to express a Bitcoin transaction's fee rate: the number of satoshis paid…

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SBI Crypto Pool

SBI Crypto Pool is a Bitcoin mining pool operated by SBI Crypto, a wholly owned subsidiary of Japan's SBI Holdings…

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Scaling Laws

Scaling laws are empirical relationships showing that a language model's prediction error (loss) decreases smoothly and predictably as you increase…

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Schelling Point

A Schelling point (or focal point) is a choice that multiple parties tend to select independently, without being able to…

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Schematic

A schematic is a diagram that represents a circuit's components and the electrical connections between them using standardized symbols, independent…

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Schnorr Batch Verification

Schnorr batch verification is a property of BIP340 signatures that lets a Bitcoin node validate a large set of signatures…

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Schnorr Signature

A Schnorr signature is the digital-signature scheme Bitcoin adopted in the November 2021 Taproot soft fork, specified in BIP340. It…

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Script Stack

The script stack is the core data structure of Bitcoin Script, the Forth-like, stack-based language that decides whether a transaction…

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SD Card Flashing (Control Board Recovery)

SD card flashing is a recovery technique for ASIC miners whose control board will no longer boot from its internal…

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SD-JWT

SD-JWT (Selective Disclosure for JWTs) is the IETF specification that retrofits privacy onto the ubiquitous JSON Web Token. Standard JWTs…

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Sealed Sender

Sealed Sender is a metadata-reduction feature in Signal that removes the sender's identity from what the server can observe. End-to-end…

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secp256k1

secp256k1 is the elliptic curve that underpins every Bitcoin private key, public key, and signature. Its name encodes its parameters:…

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Secure Boot

Secure Boot is a firmware security feature, defined in the UEFI specification, that ensures a device boots using only software…

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Secure Element

A Secure Element (SE) is a tamper-resistant hardware platform capable of securely storing cryptographic keys and confidential data, and of…

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Seed Phrase

A seed phrase (also called a recovery phrase or mnemonic) is a human-readable backup of a Bitcoin wallet's master secret,…

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Seed XOR

Seed XOR splits a BIP-39 seed into multiple phrases by combining them with the bitwise exclusive-OR (XOR) operation. Take an…

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SeedSigner

SeedSigner is an open-source project that provides firmware and assembly instructions for building a do-it-yourself, air-gapped Bitcoin signing device from…

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SegWit

Advanced

A 2017 upgrade that increased block capacity by separating signature data and enabled the Lightning Network.

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Seigniorage

Seigniorage is the profit an issuer captures by creating money, equal to the difference between the face value of the…

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Selective Disclosure

Selective Disclosure is the data-minimization principle made cryptographic: prove the one fact that is asked for, and nothing else. Instead…

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Selective State Space

Selective state space is the core innovation of the Mamba architecture, sometimes called the S6 mechanism. Classical state-space models process…

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Self-Attention

Self-attention is the core operation of the Transformer. For every token in a sequence, the model produces three learned vectors:…

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Self-Consistency

Self-consistency is a prompting technique, introduced by Wang and colleagues in 2022, that improves reasoning reliability by sampling multiple independent…

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Self-Custody

Self-custody means holding the private keys to your own Bitcoin, rather than trusting a custodian such as an exchange to…

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Self-Custody (Compute)

Self-Custody (Compute) is the application of the Bitcoin self-custody principle to computing infrastructure: running workloads — AI inference, data processing,…

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Self-Hosted Wallet (Regulatory View)

A self-hosted wallet, also called an unhosted or non-custodial wallet, is one in which the user holds their own private…

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Self-Hosting

Self-hosting is the practice of running applications and storing data on infrastructure you own and operate — a home server,…

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Self-Refine (Iterative Refinement)

Self-Refine is a prompting strategy in which one language model generates an answer, then provides written feedback on that answer,…

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Self-Signed Certificate / TLS

Transport Layer Security (TLS) is the protocol that encrypts and authenticates connections on the modern internet, securing everything from a…

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Self-Sovereign Identity (SSI)

Self-Sovereign Identity (SSI) is an approach to digital identity in which the individual, not a platform, a government, or a…

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Self-Supervised Learning

Self-supervised learning (SSL) is a training paradigm that sidesteps the need for massive human-labeled datasets by generating its own supervisory…

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Selfish Mining

Advanced

A strategy of withholding mined blocks to gain advantage over honest miners. Theoretical but rarely observed.

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Semantic Kernel

Semantic Kernel is an open-source software development kit from Microsoft for building, orchestrating, and deploying AI agents and multi-agent systems.…

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Semantic Search

Semantic search retrieves information by meaning rather than literal keyword matching. Each document and query is converted into a high-dimensional…

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Semiconductor Die

A die (plural: dies or dice) is one individual integrated circuit as it exists on, or after being cut from,…

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Semiconductor Yield

Semiconductor yield is the percentage of dies on a finished wafer that function correctly and meet specification. Because a wafer's…

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Sentence Embedding

A sentence embedding is a single fixed-length vector that represents the meaning of an entire sentence or short passage, rather…

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Sequence Number (nSequence)

The sequence number (nSequence) is a 32-bit field present on every input of a Bitcoin transaction. Originally imagined by Satoshi…

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Serial Console

A serial console is a text interface to a device's operating system that runs over a serial port rather than…

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SGLang

SGLang is an open-source, high-performance serving framework for large language models and multimodal models. Originating from research associated with UC…

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SHA-256

Intermediate

The cryptographic algorithm Bitcoin uses for mining. ASIC chips are designed specifically to compute SHA-256 at high speed.

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SHA-256 Midstate

A SHA-256 midstate is the saved internal hash state produced after processing the first 64-byte chunk of a Bitcoin block…

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Shadow Deployment

Shadow deployment is a way to test a new model under real production conditions without exposing a single user to…

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Shamir’s Secret Sharing (SLIP-39)

Shamir's Secret Sharing (SSS) is a cryptographic technique that splits a secret into a number of shares such that any…

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Shamir’s Secret Sharing (SLIP39)

Shamir's Secret Sharing (SSS), published by Adi Shamir in 1979, is a cryptographic method for splitting a secret into multiple…

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Share

Intermediate

A partial proof of work submitted to a pool to prove your miner is working. Used to calculate your reward…

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Share Difficulty

Share difficulty is the lowered target a mining pool sets for an individual miner so it can measure that miner's…

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Short Circuit

A short circuit is an unintended low-resistance connection that lets current bypass its intended path and flow in an excessive,…

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Shroud

Beginner

A duct attachment for directing miner airflow. Essential for home mining heat management and noise reduction.

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Side-Channel Attack

A side-channel attack recovers secret information by observing the physical behavior of a device as it performs a cryptographic operation,…

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SIGHASH

SIGHASH (signature hash type) is a one-byte flag attached to the end of every Bitcoin signature that declares exactly which…

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SIGHASH Flags

SIGHASH flags are single-byte codes appended to every Bitcoin signature that tell the network exactly which portions of a transaction…

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SIGHASH_ANYONECANPAY

SIGHASH_ANYONECANPAY is a modifier flag (value 0x80) that, when OR-ed with one of the three base SIGHASH modes, restricts a…

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SIGHASH_ANYPREVOUT (APO)

SIGHASH_ANYPREVOUT (APO), specified in BIP 118 and formerly known as SIGHASH_NOINPUT, is a proposed Taproot signature mode. A standard signature…

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Signal Protocol

The Signal Protocol is the open cryptographic framework that underpins end-to-end encrypted messaging in Signal, WhatsApp, and many sovereignty-focused chat…

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Signature Aggregation

Signature aggregation is the ability to collapse several signatures, or several signers' keys, into one compact Schnorr signature that the…

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Signature Operations (Sigops)

Signature operations, universally shortened to "sigops," are a count of the signature-verifying opcodes inside a transaction's scripts. Because checking an…

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Signet

Signet is a Bitcoin test network defined in BIP 325 that adds an extra signature requirement to block validation. Rather…

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Sigop Budget (Tapscript)

The sigop budget is Tapscript's mechanism (BIP 342) for limiting the computational cost of signature checking within a single spending…

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Silent Payment Scan Key

The silent payment scan key is one half of the two-key design that makes BIP352 silent payments practical. A silent…

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Silent Payments (BIP352)

Silent Payments (BIP352) is a Bitcoin wallet standard for static, reusable receiving addresses that preserve privacy. A user publishes one…

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Silicon Carbide (SiC)

Silicon Carbide (SiC) is a wide-bandgap semiconductor used in high-voltage power MOSFETs and diodes. Its bandgap of about 3.26eV, very…

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Silicon Interposer

A silicon interposer is a passive slab of silicon that sits between one or more active dies and the package…

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Silicon Wafer

A silicon wafer is the circular slice of ultra-pure, single-crystal silicon that serves as the substrate for building integrated circuits.…

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Silkscreen

Silkscreen is the layer of printed ink, usually white, applied on top of a printed circuit board's solder mask to…

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Simple Cycle

A simple cycle (or open cycle) is the most basic gas-turbine power configuration: air is compressed, mixed with fuel and…

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SimpleX Chat

SimpleX Chat is an open-source messaging network notable for having no user identifiers of any kind — no phone numbers,…

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Simplicity (Bitcoin Smart Contract Language)

Simplicity is a low-level, typed functional programming language for blockchain smart contracts, first envisioned in 2012 by Blockstream researcher Russell…

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Simplified Payment Verification (SPV)

Simplified Payment Verification (SPV) is the technique, described in Section 8 of Satoshi Nakamoto's Bitcoin whitepaper, that lets a lightweight…

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SimPO (Simple Preference Optimization)

SimPO (Simple Preference Optimization) is a reference-free method for aligning language models to human preferences. Introduced by Meng, Xia, and…

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Single-Phase Immersion Cooling

Single-phase immersion cooling submerges mining hardware in a tank of non-conductive dielectric fluid that absorbs heat but never changes state.…

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Sliding Window Attention

Sliding window attention is an attention mechanism that restricts each token to attend only to a fixed number of nearby…

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Small Modular Reactor (SMR)

A small modular reactor (SMR) is an emerging class of nuclear fission reactor with a rated electrical output below 300…

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SMT Stencil

An SMT stencil is a thin sheet of stainless steel or other foil, usually laser-cut, with apertures that line up…

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Snowflake (Transport)

Snowflake is a pluggable transport that tunnels blocked but lawful traffic through short-lived volunteer proxies running inside ordinary web browsers,…

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SNR (Radio)

Signal-to-Noise Ratio (SNR) on a radio link is the difference, expressed in decibels, between the received signal power and the…

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Social Recovery

Social recovery is an access-restoration model in which a user designates a set of trusted parties, called guardians, who can…

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Soft Fork

Advanced

A backward-compatible protocol upgrade. Old nodes still accept new blocks without upgrading.

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Soft Fork Activation

Soft fork activation refers to the mechanisms that coordinate when a backward-compatible consensus rule change takes effect across the Bitcoin…

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Soft Prompt

A soft prompt is a set of learnable vectors, often called virtual tokens, that are concatenated with a model's input…

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Soft Start

A soft start is a circuit that deliberately slows the rate at which a power supply energizes, holding the input…

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Soft Switching (ZVS/ZCS)

Soft switching is the practice of timing a power transistor's turn-on or turn-off to coincide with the instant its voltage…

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Softmax

Softmax is the function that turns a vector of arbitrary real-valued scores (logits) into a probability distribution: every output is…

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Solar-Powered Mining

Solar-powered mining uses photovoltaic panels to supply some or all of the electricity that drives an ASIC fleet. Configurations range…

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Solder Bridge

A solder bridge is an unwanted connection of solder spanning two or more conductors that are meant to be electrically…

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Solder Joint Fatigue

Solder joint fatigue is the gradual mechanical failure of a soldered connection under repeated cyclic strain. Whereas a brittle fracture…

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Solder Mask

Solder mask is the thin polymer coating applied over the copper of a printed circuit board, leaving openings only where…

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Solder Paste

Solder paste is a gray, putty-like mixture of microscopic solder alloy spheres suspended in flux and a binder. Deposited onto…

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Solder Wick (Desoldering Braid)

Solder wick, also called desoldering braid, is a fine copper braid coated with flux that is used to remove solder…

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Solo Block

Beginner

A block found by a solo miner earning the full reward. Rare for small miners but hugely celebrated.

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Solo Lottery Mining

Solo lottery mining is the practice of pointing a small amount of hashrate at the Bitcoin network in the hope…

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Solo Mining

Beginner

Mining on your own without a pool. Low odds but you keep the full block reward if you win.

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SOPR

SOPR (Spent Output Profit Ratio) is an on-chain indicator that measures, for coins moved in a given period, the ratio…

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Sound Money

Sound money is a term economists use for money whose supply is difficult to expand and that is not controlled…

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Sovereign AI

Sovereign AI is the practice of running artificial intelligence models on hardware you own, in a location you control, with…

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Sovereign Individual

The sovereign individual is a person whose economic and personal autonomy rests on technology rather than on the protection of…

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Sovereign Rollup

A sovereign rollup is a Layer 2 blockchain that publishes its transaction data to another blockchain, typically for data availability…

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Sovereign Stack

Sovereign Stack is D-Central's framework for layered self-sufficiency: the combination of Bitcoin (sound money and censorship-resistant payment rails), local AI…

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Space Heater Mining

Beginner

Using miners as heaters that also earn Bitcoin. 100% of electricity becomes useful heat in cold weather.

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Spacechain

A spacechain is a proposed type of Bitcoin sidechain that borrows Bitcoin's proof-of-work security through blind merged mining, without a…

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Sparrow Wallet

Sparrow is a Bitcoin desktop wallet built around transparency and user control, licensed under Apache 2.0. It aims to make…

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Sparse Attention

Sparse attention is a family of techniques that approximate full self-attention by letting each token attend to only a chosen…

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SPDX Identifier

An SPDX identifier is a standardized short code that uniquely names a specific software license or exception, drawn from the…

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Special Tokens

Special tokens are reserved entries in a tokenizer's vocabulary that carry structural or control meaning instead of representing literal text.…

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Specter Desktop

Specter Desktop is an open-source application for managing Bitcoin self-custody, developed under the cryptoadvance umbrella and the Specter project. It…

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Speculative Decoding

Speculative decoding is an inference optimisation that makes large language models generate text faster without changing what they would have…

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Speech-to-Text

Speech-to-text, also called automatic speech recognition (ASR), converts spoken audio into written text. The best-known open-weight example is OpenAI's Whisper,…

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Speedy Trial

Speedy Trial is a soft-fork activation strategy proposed by David Harding, based on an idea from Russell O'Connor, designed to…

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SPI (Serial Peripheral Interface)

SPI (Serial Peripheral Interface) is a synchronous serial bus that a controller chip uses to exchange data with one or…

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SPI Bus (Serial Peripheral Interface)

The Serial Peripheral Interface, or SPI, is a synchronous serial bus that moves data between a controlling processor and one…

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Spinning Reserve

Spinning reserve is unused generating capacity that is already online and synchronized to the grid, ready to increase output within…

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Splice-In

Splice-in is the act of adding fresh on-chain bitcoin to an already-open Lightning channel using one cooperative transaction, while the…

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Splice-Out

Splice-out is the act of moving bitcoin out of an open Lightning channel to an on-chain address in a single…

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Splicing

Splicing lets a Lightning node resize an existing payment channel, adding or removing funds, without closing it. The change is…

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Spreading Factor (LoRa)

Spreading Factor (SF) is a tunable parameter of LoRa radio that trades data rate against range and reliability. LoRa encodes…

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SPV Mining (Validationless Mining)

SPV mining, also called validationless mining, is the practice of beginning work on the next block using only the previous…

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SSH Access (to a Miner)

SSH access is a secure command-line login to the embedded Linux system that runs an ASIC miner's control board. Where…

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Stacking Sats

Stacking sats is a Bitcoin community phrase describing the steady accumulation of satoshis, the smallest divisible unit of bitcoin. One…

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Stale Block

Intermediate

A valid block not included in the main chain because a competing block was accepted first.

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Stale Share

A stale share is a proof of work that your miner computed correctly but submitted too late: by the time…

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Standardness

Standardness is the set of relay-policy checks a transaction must pass for a Bitcoin Core node to accept it into…

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Starlink

Starlink is SpaceX's low-Earth-orbit (LEO) satellite broadband constellation, built to deliver high-speed, relatively low-latency internet anywhere on Earth without terrestrial…

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StartOS (Start9)

StartOS is an open-source operating system developed by Start9 for personal servers. Its goal is to make running a private…

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State Space Duality

State space duality (SSD) is the theoretical framework introduced with Mamba-2 that proves a deep equivalence between certain state-space models…

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State Space Model (Mamba)

A State Space Model (SSM) is a sequence-modelling approach borrowed from control theory, in which a hidden state evolves over…

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Statechain

A statechain is an off-chain protocol that lets the ownership of an entire Bitcoin UTXO move between people without an…

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Static Pressure

Static pressure is the force a fan can exert to push air through resistance, such as a dense heatsink, an…

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Stealth Address

A stealth address is a privacy technique in which a recipient publishes a single static address, yet every payment to…

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Steel Seed Backup

A steel seed backup is a recovery seed recorded on a durable metal medium, typically stainless steel or titanium, rather…

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Stereo Microscope (Bench Microscope)

A stereo microscope, often called a bench or dissecting microscope, uses two separate optical paths to give each eye a…

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Stock-to-Flow Ratio

The stock-to-flow ratio is a measure of scarcity that divides an asset's total existing supply (the stock) by the amount…

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Store and Forward

Store and forward is a messaging pattern in which a well-resourced relay node holds onto traffic destined for peers that…

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Store of Value

A store of value is any asset that can be saved, retrieved, and exchanged later while retaining its purchasing power.…

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Stranded Energy

Intermediate

Energy that cannot reach consumers economically. Bitcoin mining can convert stranded energy into value on-site.

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Stratum Mining Channel

A mining channel is the logical pipe over which a Stratum V2 connection carries jobs and shares between a downstream…

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Stratum Mining Protocol (v1)

Stratum v1 is the de facto standard protocol that connects mining hardware to a pool. It is a line-based dialect…

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Stratum Protocol

Intermediate

The protocol miners use to communicate with pools. Stratum v2 adds encryption and miner-selected transactions.

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Stratum V1

Stratum V1 is the original pooled-mining protocol that has connected ASIC hardware to mining pools since 2012. It uses a…

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Stratum V2

Stratum V2 (SV2) is a ground-up redesign of the protocol that connects mining hardware to pools. Where the original Stratum…

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Structured Output (JSON Mode)

Structured output — often called JSON mode when the target format is JSON — is the practice of forcing a…

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Stubborn Mining

Stubborn mining is a family of strategies that generalizes selfish mining by changing how an attacker behaves when it falls…

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Sub-Quadratic Attention

Sub-quadratic attention is an umbrella term for sequence-mixing methods whose time and memory cost grow more slowly than the square…

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Submarine Swap

A submarine swap is a trustless exchange between on-chain Bitcoin and off-chain Lightning balance. It is a specific kind of…

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Subnet / CIDR

A subnet (subnetwork) is a logical subdivision of an IP network, and CIDR (Classless Inter-Domain Routing) is the notation and…

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Superficial Loss Rule

The superficial loss rule is a Canada Revenue Agency (CRA) anti-avoidance rule, sometimes called the "30-day rule," that prevents you…

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Supply Chain Attack (Hardware)

A hardware supply chain attack compromises a device before it ever reaches the end user, by inserting malicious functionality or…

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Surge Protection

Surge protection refers to the devices and design practices that defend electrical and electronic equipment against transient overvoltages—brief, high-energy spikes…

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Surveillance Capitalism

Surveillance capitalism is a term coined by Harvard professor Shoshana Zuboff to describe an economic logic that, in her words,…

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Sweep (Wallet)

To sweep a private key is to broadcast a transaction that sends the entire balance from an address controlled by…

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Switchboard

A switchboard is an electrical distribution assembly that receives power from a single large incoming feed and divides it among…

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Switchgear

Switchgear is the collective term for the circuit breakers, disconnect switches, fuses, busbars, meters, and protective relays assembled to control,…

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Switching Frequency

Switching frequency is the rate at which a switch-mode power supply's transistors turn on and off, typically tens of kilohertz…

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Sybil Attack

A Sybil attack is a peer-to-peer network attack in which a single adversary creates a large number of pseudonymous identities…

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Sycophancy (LLM)

Sycophancy is the tendency of a language model to align its answers with a user's stated beliefs, framing, or assumptions,…

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Synchronous Rectification

Synchronous rectification (SR) is the technique of replacing the rectifying diode on a converter's output with an actively gated MOSFET.…

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Synthetic Data

Synthetic data is artificially generated information that reproduces the statistical properties of a real dataset without copying its actual records.…

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Synthetic Inertia

Synthetic inertia, also called virtual inertia, is a control technique that makes an inverter-based resource — a battery, solar plant,…

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System Bus

A system bus is the communication pathway that ties a processor together with memory and peripherals, carrying the data, addresses,…

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System Prompt

A system prompt is the standing instruction an application gives a language model before the user ever types anything. It…

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System-on-Chip (SoC)

A System-on-Chip (SoC) integrates the major building blocks of a computer — processor cores, memory controllers, peripheral interfaces, and often…

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T

Tails OS

Tails (The Amnesic Incognito Live System) is a portable, Debian-based operating system that runs as a live image from a…

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Tainted Coins

"Tainted coins" is the informal label for bitcoin that blockchain-analysis firms or exchanges have flagged because their transaction history links…

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TapBranch

TapBranch is the internal-node hash function used to assemble a Taproot script tree from its leaves up to a single…

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Tape-Out

Tape-out is the point in chip development at which the design is considered final and the complete layout database is…

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Tapleaf

A tapleaf is one leaf of the Merkle tree that Taproot commits to alongside its internal public key. Each tapleaf…

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Taproot

Advanced

A 2021 upgrade adding Schnorr signatures for better privacy and efficiency in complex Bitcoin transactions.

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Taproot (BIP341)

Taproot, defined in BIP341 and activated at block 709,632 in November 2021, is the soft fork that gave Bitcoin a…

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Taproot Annex

The annex is an optional final element in a Taproot input's witness, recognized by a leading 0x50 byte. It is…

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Taproot Assets

Taproot Assets, formerly named Taro (Taproot Asset Representation Overlay), is a protocol from Lightning Labs for issuing and transferring assets…

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Taproot Internal Key

The Taproot internal key, written P in BIP341, is the public key a wallet selects as the foundation of a…

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Taproot Merkle Path

The Taproot merkle path is the sequence of sibling node hashes a spender supplies to prove that a particular script…

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Taproot Output Key

The Taproot output key, denoted Q in BIP341, is the 32-byte X-only public key that actually appears in a Pay-to-Taproot…

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Taproot Tweak

The Taproot tweak is the cryptographic operation at the heart of BIP341 that fuses a single public-key spending condition with…

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Tapscript

Tapscript is the version of Bitcoin Script used when a Taproot output is spent via its script path. Specified in…

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Target

Advanced

The threshold a block hash must be below to be valid. Lower target means harder mining.

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Target (Mining)

The target is the 256-bit number that defines what counts as a winning hash in Bitcoin mining. For a block…

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TCP/IP

TCP/IP is the foundational protocol suite of the internet, named after its two core protocols: the Transmission Control Protocol (TCP)…

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TDP

Intermediate

The maximum heat output of a miner in watts. Equal to power consumption since all electricity becomes heat.

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Temperature (Sampling)

Temperature is the sampling parameter that controls how random a language model's output is at inference time. After the model…

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Temperature Sensor

Intermediate

Sensors monitoring chip and ambient temperatures to prevent overheating and control fan speeds.

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Template Distribution Protocol

The Template Distribution Protocol (TDP) is the Stratum V2 sub-protocol that moves freshly built block templates from a Bitcoin node,…

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Template Provider

A Template Provider is the Stratum V2 component that constructs candidate block templates from a node's mempool and serves them…

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Tensor Core

A Tensor Core is a specialized execution unit inside modern NVIDIA GPUs, first introduced with the Volta architecture. Where a…

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Tensor Parallelism

Tensor parallelism, also known as horizontal or intra-layer parallelism, divides the math inside a single layer across multiple accelerators. Instead…

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TensorRT-LLM

TensorRT-LLM is an open-source library from NVIDIA for optimizing the inference of large language models on NVIDIA GPUs. Released publicly…

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Terahash (TH/s)

A terahash per second (TH/s) is one trillion — 1012, or 1,000,000,000,000 — double-SHA-256 hash attempts every second. It is…

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Test Fixture

A test fixture is a bench rig that lets a technician power and scan a single hashboard outside the miner…

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Test-Time Compute (Inference-Time Scaling)

Test-time compute, also called inference-time scaling, is the practice of allocating more computation when a model answers a question rather…

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Testnet

Testnet is a parallel Bitcoin blockchain that lets developers and tinkerers experiment with transactions, wallets, and applications using coins that…

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Text Generation Inference (TGI)

Text Generation Inference (TGI) is an open-source toolkit, maintained by Hugging Face, for deploying and serving large language models behind…

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text-generation-webui (oobabooga)

text-generation-webui, widely known by its maintainer's handle “oobabooga,” is an open-source Gradio web interface for running large language models locally.…

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Text-to-Speech

Text-to-speech (TTS) synthesizes spoken audio from written text. Modern neural TTS produces voices natural enough to be hard to distinguish…

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Thermal Fatigue

Thermal fatigue is the progressive cracking of solder joints and interconnects caused by repeated heating and cooling cycles rather than…

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Thermal Interface Material (TIM)

Thermal interface material (TIM) is the paste, grease, or pad applied between a heat-generating component and its heatsink to improve…

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Thermal Pad

A thermal pad is a pre-formed sheet of conductive, pliable material, usually silicone loaded with ceramic or other fillers, placed…

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Thermal Paste

Beginner

A compound applied between chips and heatsinks for better heat transfer. Regular replacement improves miner performance.

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Thermal Resistance

Thermal resistance quantifies how strongly a material, joint, or path opposes the flow of heat, much as electrical resistance opposes…

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Thermal Shim

A thermal shim is a thin, precisely sized piece of conductive metal, usually copper, inserted into a cooling interface to…

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Thermal Throttling

Thermal throttling is a protective behavior built into mining ASIC firmware: when a chip's junction temperature approaches its safe limit,…

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Thermocap

Thermocap is an on-chain aggregate equal to the cumulative USD value of all revenue paid to miners over the entire…

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Thiers’ Law

Thiers' Law is the inverse of Gresham's Law. Where Gresham's Law observes that "bad money drives out good" — people…

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Threat Model

A threat model is a deliberate, written assessment of the risks you actually face, used to decide where to spend…

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Threat Modeling

Threat modeling is the disciplined practice of asking, before you build or deploy a system, "What can go wrong, who…

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Three-Phase Power

Three-phase power is an alternating-current system that delivers electricity over three conductors, each carrying a current offset from the others…

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Threshold ECDSA

Threshold ECDSA lets a group of parties collaboratively produce a valid ECDSA signature without any single participant ever possessing the…

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Through-Silicon Via (TSV)

A through-silicon via, or TSV, is a vertical electrical connection that passes completely through a silicon die, wafer, or interposer.…

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Throughput vs Latency (LLM Inference)

Throughput versus latency is the central trade-off when serving large language models (LLMs). Latency measures how fast one request is…

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Throughput-Optimized Serving

Throughput-optimized serving is a way of configuring a large language model inference server to maximize the total number of tokens…

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Time Preference

Time preference is an economic concept describing how much people value having goods now versus the same goods in the…

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Time To First Token (TTFT)

Time to first token (TTFT) measures how long a large language model (LLM) takes to produce its very first output…

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Time-of-Use Rate

A time-of-use (TOU) rate is an electricity tariff in which the price per kilowatt-hour varies according to the time of…

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Time-Warp Attack

The time-warp attack exploits a quirk in Bitcoin's difficulty-adjustment algorithm. Difficulty retargets every 2,016 blocks based on the time elapsed…

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Timechain

Timechain is the name Satoshi Nakamoto originally used for the data structure the world now calls the blockchain. The term…

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Timestamp

Intermediate

The time recorded in a block header when the block was mined, used for difficulty adjustments.

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Tin Whisker

A tin whisker is a thin, electrically conductive single-crystal filament that grows spontaneously from pure or tin-rich metal surfaces. Whiskers…

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Token Budget / Rate Limiting

Token budgeting and rate limiting are the controls that govern how much work a large language model endpoint will accept…

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Tokenizer

A tokenizer is the component that converts raw text into the numeric tokens a language model actually processes. LLMs do…

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Tokenizer Vocabulary

A tokenizer vocabulary is the fixed dictionary of tokens a language model can read and emit. It is the bridge…

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Tokens

A token is the basic unit of text a large language model actually processes. Models do not read characters or…

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Tokens per Second

Tokens per second (TPS) is the primary metric for how fast a large language model produces text. It is simply…

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Tombstoning

Tombstoning, also called the Manhattan effect or drawbridge effect, is a surface-mount soldering defect in which a small two-terminal component…

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Tool Schema (JSON Schema for Tools)

A tool schema is the structured definition that tells a language model what an external tool does and how to…

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Tool Use

Tool use is the capability that separates an AI agent from a plain chatbot: the model can call out to…

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Top-k Sampling

Top-k sampling is a decoding strategy that limits a language model's choice of next token to the k highest-probability candidates…

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Top-p (Nucleus Sampling)

Top-p sampling, also called nucleus sampling, is a decoding strategy that controls the randomness of a language model's output. At…

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TOPS (Tera Operations Per Second)

TOPS, or Tera Operations Per Second, is the headline throughput rating stamped on neural processing units (NPUs), edge AI accelerators,…

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Tor (The Onion Router)

Tor (The Onion Router) is a free, open-source anonymity network that conceals who is talking to whom by routing each…

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Tor Bridge

A Tor bridge is an entry relay into the Tor anonymity network whose IP address is deliberately kept off the…

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Total Harmonic Distortion (THD)

Total Harmonic Distortion (THD) measures how much a voltage or current waveform departs from an ideal sine wave. Formally, it…

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TPU (Tensor Processing Unit)

A Tensor Processing Unit (TPU) is an application-specific integrated circuit (ASIC) developed by Google to accelerate machine-learning workloads. Rather than…

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Trace Current Capacity

Trace current capacity, or ampacity, is the maximum current a PCB trace can carry before it heats up beyond an…

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Traffic Obfuscation

Traffic obfuscation is the practice of reshaping a network connection's bytes, packet sizes, and timing so that an observer cannot…

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Train-Test Split

A train-test split is the practice of dividing a dataset into separate subsets so that a model is evaluated on…

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Training-Data Extraction

Training-data extraction is an attack in which an adversary recovers actual examples from a model's training set using only query…

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Trampoline Routing

Trampoline routing is a Lightning Network technique that lets a sending node delegate route calculation to a better-connected intermediary, called…

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Transaction Accelerator

A transaction accelerator is a tool that helps a stuck Bitcoin transaction confirm sooner than its fee rate would otherwise…

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Transaction Fees

Beginner

Fees users pay for miners to process their transactions. Becomes more important as block rewards decrease.

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Transaction Fingerprinting

Transaction fingerprinting (also called wallet fingerprinting) is the practice of inferring which wallet software built a Bitcoin transaction from the…

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Transaction Graph

The transaction graph is the network of connections that Bitcoin transactions create between addresses over time. Because every output spent…

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Transaction Index (txindex)

The transaction index, enabled with -txindex=1, is an optional LevelDB database that records where every transaction lives inside the block…

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Transaction Pinning Attack

A transaction pinning attack abuses the very mempool limits that protect nodes from denial of service, turning them into a…

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Transaction Propagation

Transaction propagation is how a newly broadcast Bitcoin transaction spreads across the peer-to-peer network. Starting from the originating node, the…

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Transformer

The Transformer is a neural network architecture introduced in the 2017 paper Attention Is All You Need by Vaswani and…

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Transient (Voltage Spike)

A transient, often called a voltage spike or surge, is a very short, sharp deviation from the normal waveform. IEEE…

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Transistor Density

Transistor density measures how many transistors a process can pack into a given area of silicon, most often expressed in…

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Tree-of-Thought

Tree-of-Thought (ToT) is a prompting and inference framework, introduced by Yao and colleagues in 2023, that generalises step-by-step reasoning into…

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Trezor

Trezor is a line of hardware wallets made by SatoshiLabs, a company founded in Prague. The original Trezor Model One,…

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Triffin Dilemma

The Triffin Dilemma describes the inherent conflict of interest a country faces when its national currency also serves as the…

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Trigeneration

Trigeneration, also known as combined cooling, heat and power (CCHP), produces three useful outputs from a single fuel input: electricity,…

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Triplen Harmonics

Triplen harmonics are the odd multiples of the third harmonic: the 3rd, 9th, 15th, 21st, and so on. They are…

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TRUC Transactions (v3)

TRUC stands for Topologically Restricted Until Confirmation, an opt-in mempool policy signalled by setting a transaction's nVersion field to 3.…

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Trusted Platform Module (TPM)

A Trusted Platform Module (TPM) is a secure cryptoprocessor, standardized as ISO/IEC 11889, that provides hardware-based cryptographic functions and tamper-resistant…

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Trusted Setup Ceremony

A trusted setup ceremony is a multi-party computation that generates the public parameters, often called the structured reference string or…

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Trustless

Trustless is shorthand for a system in which participants do not have to trust each other or a central intermediary,…

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TTL Logic Level

A logic level is the voltage range a digital line uses to represent a binary 1 or 0. TTL logic…

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Turndown Ratio

Turndown ratio describes how wide an operating range a power source can cover, defined as the ratio of its maximum…

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Two-Phase Immersion Cooling

Two-phase immersion cooling exploits a phase change to move heat. Hardware sits in a sealed tank filled with a dielectric…

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U

UART (Serial Console)

UART (Universal Asynchronous Receiver/Transmitter) is a simple asynchronous serial interface that moves data over two signal wires — transmit (TX)…

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UASF (User-Activated Soft Fork)

A User-Activated Soft Fork (UASF) is a method of deploying a Bitcoin consensus change in which ordinary full nodes —…

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Unconfirmed Transaction

An unconfirmed transaction is one that nodes have validated and accepted into their mempools but that no miner has yet…

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Underclocking

Intermediate

Running mining hardware slower to reduce power, heat, and noise. Essential for home mining setups.

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Underfill

Underfill is the epoxy adhesive injected into the gap between a BGA chip and the PCB to mechanically reinforce the…

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Underfitting

Underfitting is the opposite failure mode to overfitting. It occurs when a model is too simple, or trained too briefly,…

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Undervolting

Intermediate

Lowering chip voltage to reduce power consumption and heat, improving efficiency for home mining.

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Uninterruptible Power Supply (UPS)

An Uninterruptible Power Supply (UPS) is a device that provides instantaneous backup power when the incoming mains fails, sags, or…

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Unit Bias

Unit bias is a cognitive heuristic from behavioral economics describing the human tendency to treat a single unit of something…

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Unit of Account

A unit of account is one of the three classical functions of money: the standard numerical measure people use to…

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Uptime / Availability

Uptime, or availability, is the proportion of time a facility operates without interruption, usually expressed as a percentage and shorthanded…

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USB-to-Serial Adapter

A USB-to-serial adapter is a small bridge that turns a modern computer's USB port into a serial line a device…

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Utreexo

Utreexo is a dynamic, hash-based cryptographic accumulator designed by Tadge Dryja to shrink Bitcoin's Unspent Transaction Output set from gigabytes…

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UTXO

A UTXO (Unspent Transaction Output) is a discrete amount of bitcoin that has been received and not yet spent. Bitcoin…

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UTXO Commitment

A UTXO commitment is a compact cryptographic summary of the complete set of unspent transaction outputs, the current spendable balances…

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UTXO Consolidation

UTXO consolidation is the practice of merging many small Unspent Transaction Outputs into one or a few larger UTXOs. Every…

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UTXO Labeling

UTXO labeling is the practice of attaching human-readable notes to the records in a wallet: individual transactions, addresses, inputs, outputs,…

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V

Validity Rollup (Bitcoin)

A validity rollup is a Layer 2 blockchain that proves the correctness of its state transitions to a base layer…

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Vanity Address

A vanity address is a Bitcoin address deliberately generated to contain a chosen, human-readable pattern, such as a name, brand,…

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Vapor Chamber

A vapor chamber is a sealed, flattened two-phase heat-transfer device, essentially a planar heat pipe, that spreads concentrated heat from…

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Vardiff (Variable Difficulty)

Vardiff, short for variable difficulty, is the system a mining pool uses to automatically set and adjust the share difficulty…

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Variational Autoencoder (VAE)

A variational autoencoder (VAE) is a probabilistic generative model, introduced by Kingma and Welling in 2013, that learns a smooth,…

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Variational Autoencoder (VAE)

A Variational Autoencoder (VAE) is a generative model that learns a probabilistic mapping between high-dimensional data and a lower-dimensional latent…

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VASP (Virtual Asset Service Provider)

A Virtual Asset Service Provider (VASP) is the Financial Action Task Force's umbrella term for any business that, as a…

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Veblen Good

A Veblen good is a type of good for which demand increases as price increases, producing an upward-sloping demand curve…

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Vector Commitment

A vector commitment lets a prover commit to an ordered sequence of values with a single short string, then later…

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Vector Database

A vector database is a storage system purpose-built to hold embedding vectors and answer the question "which stored items are…

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Vector Quantization

Vector quantization (VQ) is a lossy compression technique borrowed from signal processing and now central to efficient embedding search. It…

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Vector76 Attack

The Vector76 attack, also called the one-confirmation attack, is a double-spend strategy that combines elements of the Finney Attack and…

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Verifiable Credential

A Verifiable Credential (VC) is a digital, cryptographically signed statement of claims, such as a diploma, a membership, or proof…

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Verifiable Presentation

A Verifiable Presentation is how a holder actually shows up to be checked. Where a credential is data signed by…

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Verifier Model

A verifier model is a model whose job is to judge the output of another model rather than to produce…

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Verify, Don’t Trust

"Don't trust, verify" is the operational mantra of the sovereign Bitcoiner. It turns the abstract property of trustlessness into a…

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Verkle Tree

A Verkle tree is an authenticated data structure whose name fuses Vector commitment and Merkle tree. It replaces the hash-based…

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Version

Advanced

A block header field that indicates the block format version and signals support for protocol upgrades.

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Version Bits (BIP 9 / BIP 8)

Version bits are Bitcoin's standard way for miners to signal readiness for a soft fork by setting individual bits in…

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Version Rolling (BIP 310)

Version rolling is a mining technique that treats reserved bits of the block header's nVersion field as an additional source…

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Via

A via is a plated hole that carries an electrical connection from one copper layer of a printed circuit board…

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Via Stitching

Via stitching is the placement of a periodic array of vias that connect copper planes, usually ground planes, across the…

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ViaBTC

ViaBTC is a Bitcoin mining pool founded in 2016 by Haipo Yang, who wrote the initial pool software himself. The…

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Virtual Byte (vByte)

A virtual byte (vByte or vB) is the everyday unit Bitcoiners use to size transactions and price fees. It is…

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Virtual Byte (vByte)

A virtual byte (vByte, or vB) is the unit used to measure a Bitcoin transaction's size for fee purposes after…

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Virtual Power Plant (VPP)

A virtual power plant (VPP) is a network of distributed energy resources — rooftop solar, home and grid batteries, EV…

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Vision Encoder

A vision encoder is the part of a multimodal system responsible for turning raw pixels into a numerical representation that…

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Vision Transformer (ViT)

The Vision Transformer (ViT) is an image model, introduced by Google researchers in 2020, that applies the transformer architecture, originally…

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Vision-Language Model

A vision-language model (VLM) is a multimodal architecture that combines visual perception with language understanding, letting a single model take…

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Visual Question Answering (VQA)

Visual Question Answering (VQA) is a multimodal task in which a system is given an image and a free-form natural-language…

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Visual Token

A visual token is the unit by which an image enters a multimodal language model. A vision encoder splits a…

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VLAN (Virtual LAN)

A VLAN (Virtual Local Area Network) is a logically separate network created on top of shared physical switching hardware. It…

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vLLM

vLLM is an open-source library for fast LLM inference and serving, originally developed at UC Berkeley's Sky Computing Lab. Where…

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Voltage Domain

A voltage domain is a group of hashing ASIC chips on a mining hashboard that are wired in series and…

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Voltage Drop

Voltage drop is the reduction in voltage between the source and the load caused by the resistance of the conductors…

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Voltage Flicker

Voltage flicker is the visible fluttering of lighting caused by repeated, rapid variations in supply voltage. It is not a…

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Voltage Regulator

Advanced

Components that convert 12V power to the precise low voltage ASIC chips need. A common failure point in miners.

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Voltage Sag

A voltage sag (also called a dip) is a short-duration decrease in RMS voltage. Under IEEE 1159, a sag is…

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Voltage Swell

A voltage swell is the inverse of a sag: a temporary increase in RMS voltage above nominal. IEEE 1159 defines…

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VRAM

VRAM (Video Random Access Memory) is the high-speed memory built into a graphics card. For gaming it holds textures and…

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W

Wallet Backup: Seed vs Descriptor

A wallet backup protects your ability to recover funds, but not all backups capture the same information. A seed phrase,…

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Wallet Clustering

Wallet clustering is the technique surveillance firms use to lump together the many addresses that probably belong to a single…

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Warrant Canary

A warrant canary is a regularly published statement affirming that a service provider has not received a particular kind of…

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Waste Heat Recovery

Waste heat recovery is the practice of capturing thermal energy that a process or machine would otherwise reject to the…

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Watch-Only Wallet

A watch-only wallet holds only public key material, typically an extended public key (xpub) or a full output descriptor, and…

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Watchtower

A watchtower is a service that monitors the Bitcoin blockchain on a Lightning node's behalf, defending its channels against breaches…

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Water Usage Effectiveness (WUE)

Water Usage Effectiveness (WUE) measures how much water a facility consumes to cool its compute load, expressed in liters of…

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Wavelength

Wavelength is the physical distance a radio wave travels during one complete cycle of its oscillation. It is found by…

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Web of Trust

A Web of Trust is a decentralized model for establishing trust and authenticity without a central authority. Rather than relying…

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WebLN

WebLN is a JavaScript interface to the Bitcoin Lightning Network that lets a web application interact with the user's Lightning…

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Weight Unit

A weight unit (WU) is the fundamental unit Bitcoin uses to measure how much of a block a transaction occupies.…

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Whale

In crypto markets, a whale is an individual or entity that holds a very large amount of an asset —…

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Wheeling

Wheeling is the transport of electric power from a generator to a buyer over transmission or distribution lines owned by…

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Whirlpool

Whirlpool is a Chaumian CoinJoin implementation built on the ZeroLink framework, originally developed by the Samourai Wallet team. Its goal…

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Whonix

Whonix is a free and open-source operating system built on Debian GNU/Linux and the Kicksecure hardened base, designed for anonymity…

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Wind-Powered Mining

Wind-powered mining connects ASIC miners to wind generation, frequently to soak up energy that would otherwise be curtailed. Wind farms…

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Winlink

Winlink Global Radio Email is a volunteer-operated system, run by the Amateur Radio Safety Foundation, that lets licensed operators send…

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Wire Bonding

Wire bonding is the oldest and still most common first-level interconnect in semiconductor packaging. It joins the bond pads on…

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WireGuard

WireGuard is a modern VPN protocol designed for simplicity, speed, and a small, auditable codebase. It creates an encrypted tunnel…

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Witness Commitment

The witness commitment is the mechanism SegWit (BIP-141) uses to bind a block to its segregated witness data. Because SegWit…

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Witness Stack

The witness stack is the part of a Segregated Witness (SegWit) transaction input that holds the signatures and any script…

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World Model

A world model is an AI system that learns an internal representation of how an environment behaves, so it can…

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Wrench Attack

A wrench attack is the use of physical force, threats, or coercion to make someone reveal a password, seed phrase,…

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Wumbo Channel

A wumbo channel is a Lightning Network payment channel whose capacity exceeds the original protocol cap of 0.1677 BTC (16,777,215…

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Wye vs Delta Wiring

Wye and delta are the two fundamental ways three-phase transformer windings are connected, and which one a facility uses determines…

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Z

Zap

A Zap is a Bitcoin micropayment sent across the Nostr network using the Lightning Network. Where a conventional social platform…

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ZeRO (Zero Redundancy Optimizer)

The Zero Redundancy Optimizer (ZeRO) is a family of memory optimizations in Microsoft's DeepSpeed library. Ordinary data parallelism wastes memory…

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Zero Trust Architecture

Zero trust architecture (ZTA) abandons the old assumption that anything inside a network perimeter is automatically trustworthy. Its operating principle…

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Zero-conf Channel

A zero-confirmation (zero-conf) channel is a Lightning Network payment channel that can send and receive immediately after its funding transaction…

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Zero-Confirmation Transaction (0-conf)

A zero-confirmation transaction, often shortened to 0-conf, is a valid Bitcoin transaction that has been broadcast to the network and…

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Zero-Knowledge Proof

A zero-knowledge proof (ZKP) is a cryptographic protocol that allows one party, the prover, to convince another party, the verifier,…

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ZeRO-Offload / CPU Offload

ZeRO-Offload is a training technique that relocates the heaviest memory consumers, the optimizer states and gradients, from scarce GPU memory…

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Zero-Shot Prompting

Zero-shot prompting presents a task to a language model using nothing but an instruction — no worked examples are provided.…

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zk-SNARK

A zk-SNARK, short for Zero-Knowledge Succinct Non-Interactive Argument of Knowledge, is a specific construction of a zero-knowledge proof that produces…

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zk-STARK

A zk-STARK, short for Zero-Knowledge Scalable Transparent Argument of Knowledge, is a zero-knowledge proof system designed to avoid the trusted…

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Zynq SoC

The Zynq SoC is a family of system-on-chip devices from Xilinx (now part of AMD) that fuses a dual-core ARM…

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