Whether you just unboxed your first Bitaxe or you are running a fleet of Antminers in your garage, the language of Bitcoin mining can feel like its own dialect. Hashrate, J/TH, nonce, epoch, PPLNS — the jargon piles up fast. This glossary exists to cut through the noise. Every term is defined in plain language, with technical depth where it matters and links to our in-depth guides where you can go deeper.
We built this reference for home miners, repair technicians, Bitaxe tinkerers, and anyone who believes in decentralizing Bitcoin’s hashrate. Bookmark it. Share it. Come back whenever you hit an unfamiliar term in a setup guide, firmware changelog, or pool dashboard. This is your field manual.
A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | Z
A
Antminer
The flagship line of ASIC miners manufactured by Bitmain, the largest Bitcoin mining hardware company in the world. Antminer models are identified by letter-number combinations like S9, S19, S21, and T21, where the letter typically indicates the mining algorithm series and the number indicates the generation. Antminers dominate the SHA-256 mining market and are the most widely serviced machines in the ASIC repair industry. D-Central stocks, repairs, and customizes Antminers — including our purpose-built Slim Edition and Loki Edition variants for home miners.
ASIC (Application-Specific Integrated Circuit)
A microchip designed and manufactured to perform one task — and only that task — as efficiently as possible. In Bitcoin mining, ASICs are engineered to compute SHA-256 hashes at extraordinary speeds. Unlike GPUs or CPUs that handle general computing, an ASIC miner sacrifices flexibility for raw performance, delivering thousands of times more hashes per watt than general-purpose hardware. Every modern Bitcoin miner — from a Bitmain Antminer to a solo-mining Bitaxe — is built around ASIC chips. See also: ASIC Chip.
ASIC Chip
The individual silicon die inside an ASIC miner that performs the actual SHA-256 hashing computations. A single hashboard may contain dozens or even hundreds of ASIC chips. Chip generations are typically identified by model numbers such as Bitmain’s BM1366, BM1368, and BM1370. Chip manufacturing process (measured in nanometers) directly determines mining efficiency — smaller process nodes produce more hashes per joule. D-Central carries replacement ASIC chips for repair work.
ASIC Repair
The specialized process of diagnosing and fixing faults in ASIC mining hardware at the component level — replacing failed ASIC chips, reflowing solder joints, repairing hashboard traces, and rebuilding control boards. ASIC repair requires specialized equipment including hot-air rework stations, multimeters, oscilloscopes, and thermal cameras. D-Central operates one of the largest ASIC repair operations in North America, servicing all major brands. See our full ASIC repair services page and our guide on professional repair vs DIY.
Auto-tuning
A firmware feature that automatically adjusts the voltage and clock frequency of individual ASIC chips to find the optimal balance between hashrate and power consumption. Rather than applying one setting across all chips, auto-tuning tests each chip individually and assigns custom parameters. Third-party firmware like Braiins OS+ pioneered this feature, and it is now available in several firmware options. Auto-tuning is especially valuable for home miners who need to stay within household electrical limits. See our Braiins OS+ setup guide for configuration details.
AxeOS
The open-source firmware that powers all Bitaxe solo miners. AxeOS runs on an ESP32 microcontroller and provides a web-based interface for configuring your mining pool, adjusting core voltage and frequency, monitoring temperatures, and updating firmware over-the-air (OTA). It is lightweight, fully open-source, and designed specifically for the Bitaxe hardware family. D-Central has a comprehensive AxeOS settings guide covering every configuration option.
B
Best Difficulty (Best Share)
The highest-difficulty share your miner has ever submitted to a pool, representing the closest you have come to finding a valid block. In solo mining, your “best difficulty” or “best share” is a bragging-rights metric — the closer it gets to the network difficulty, the closer you came to winning a block. AxeOS displays this value on the Bitaxe dashboard. While statistically meaningless for predicting future results (each hash is independent), it is a motivating indicator that your device is contributing real work.
Bitaxe
An open-source, standalone Bitcoin solo miner built around a single (or multiple) ASIC chip(s) on a compact PCB. Bitaxe devices run AxeOS firmware and connect directly to a mining pool via Wi-Fi — no separate controller or computer required. Models include the Supra, Ultra (BM1366), Gamma (BM1370), GT (dual BM1370), and Hex (six BM1366 chips). D-Central is a pioneer in the Bitaxe ecosystem, having created the original Bitaxe Mesh Stand and developed leading cooling solutions and accessories. Explore every model in our Bitaxe Hub or read our Bitaxe comparison guide.
Bitcoin Halving
A programmatic event hard-coded into the Bitcoin protocol that cuts the block reward in half approximately every 210,000 blocks (roughly every four years). The most recent halving in April 2024 reduced the block reward from 6.25 BTC to 3.125 BTC. Halvings enforce Bitcoin’s fixed monetary policy of 21 million coins and have historically been catalysts for mining industry consolidation as less efficient machines become unprofitable. Read our guide on preparing for the 2028 halving.
Block Height
The sequential number assigned to each block in the Bitcoin blockchain, starting from block 0 (the genesis block). Block height serves as a universal reference point — when miners or pool dashboards report that a block was found, they identify it by its height. Block height also determines when protocol events like the halving and difficulty adjustments occur.
Block Reward
The total Bitcoin payout a miner receives for successfully mining a valid block. It consists of two components: the block subsidy (newly minted BTC, currently 3.125 BTC post-2024 halving) and the sum of all transaction fees included in that block. The block reward is what makes mining economically viable and is the incentive structure that secures the Bitcoin network. Solo miners receive the full block reward; pool miners share it according to the pool’s payout scheme.
Block Template
The pre-assembled structure of a candidate block that a miner hashes against, containing the set of transactions selected from the mempool, the coinbase transaction, and all block header fields except the nonce. Traditionally, mining pools construct block templates and distribute them to all connected miners. Protocols like Stratum V2 and DATUM allow individual miners to build their own block templates using their full node, reclaiming a crucial aspect of mining sovereignty.
BM1366
A Bitmain-manufactured ASIC chip built on a 5nm process node, originally developed for the Antminer S19 XP series. The BM1366 is also the chip used in the Bitaxe Supra, Ultra, and Hex models. At stock settings, a single BM1366 produces roughly 500-600 GH/s, though overclocking can push it higher. Its combination of efficiency and availability has made it the most popular chip in the open-source solo mining community. See our Bitaxe Ultra setup guide for BM1366 configuration details.
BM1368
A Bitmain ASIC chip that powers the Antminer S21 standard series. The BM1368 delivered a significant efficiency improvement over the BM1366, achieving roughly 15 J/TH at the system level in the S21. While not yet as widely adopted in open-source hardware as the BM1366 or BM1370, it represents an important step in Bitmain’s chip roadmap. See our Antminer S21 review for performance benchmarks.
BM1370
Bitmain’s latest-generation SHA-256 ASIC chip, used in the Antminer S21 Pro and adopted by the Bitaxe Gamma and GT models. The BM1370 offers improved efficiency over the BM1368, delivering more hashes per joule. In the Bitaxe Gamma, a single BM1370 produces roughly 1.0-1.2 TH/s at stock settings, with overclocking pushing it beyond 2 TH/s. Read our Bitaxe Gamma 602 review for real-world performance data.
Braiins OS+
A third-party Linux-based firmware for Antminer hardware, developed by the team behind Slush Pool (now Braiins Pool). Braiins OS+ is known for its auto-tuning feature, Stratum V2 support, per-chip voltage optimization, and detailed performance telemetry. It is one of the three major aftermarket Antminer firmware options alongside VNish and LuxOS. Read our full firmware comparison and Braiins OS+ setup guide.
BTU (British Thermal Unit)
A unit of heat energy equal to the amount needed to raise the temperature of one pound of water by one degree Fahrenheit. In Bitcoin mining, BTU output matters because every watt consumed by an ASIC miner is converted almost entirely into heat. Knowing the BTU output of your miner is essential when sizing it as a space heater or planning cooling infrastructure. One watt of power produces approximately 3.412 BTU/hour. Use our Bitcoin Space Heater BTU Calculator to size your setup.
C
CKPool
A lightweight, open-source Bitcoin mining pool software (and the public pool that runs it) created by developer Con Kolivas. CKPool is the most popular pool endpoint for solo miners, including most Bitaxe users, because it offers a no-fee or low-fee solo mining mode. When your Bitaxe finds a block through CKPool, you receive the entire block reward. CKPool’s solo endpoint (solo.ckpool.org) is the default pool configured in most AxeOS setups.
Coinbase Transaction
The first transaction in every Bitcoin block, created by the miner who found the block. Unlike regular transactions that transfer existing bitcoin between addresses, the coinbase transaction creates new bitcoin out of thin air — it is how the block subsidy enters circulation. The coinbase transaction also includes the collected transaction fees from all other transactions in the block. Miners can embed arbitrary data in the coinbase transaction, which is how Satoshi’s famous “Chancellor on the brink” message was encoded in the genesis block.
Control Board
The main circuit board in an ASIC miner that manages communication, network connectivity, firmware execution, and coordination of the hashboards. The control board connects to your network via Ethernet, runs the miner’s operating system, distributes work to each hashboard, and reports results back to the mining pool. It is essentially the brain of the miner. Control board failures are one of the most common repair issues we handle. See our control board vs hashboard guide for a deeper breakdown.
Core Voltage
The electrical voltage supplied to the ASIC chips on a hashboard. Core voltage is the primary lever for controlling power consumption and hashrate. Lowering voltage (undervolting) reduces power draw and heat but also decreases hashrate. Raising voltage (overclocking) increases hashrate at the cost of higher power consumption and thermal output. Fine-tuning core voltage is how miners optimize their J/TH efficiency to match their electricity costs and cooling capacity.
Cooling Distribution Unit (CDU)
A specialized heat-exchange system used in hydro-cooled mining operations. The CDU circulates coolant between the mining hardware and an external heat rejection system (such as a dry cooler or radiator). CDUs manage flow rate, temperature, and pressure to keep ASIC chips within safe thermal limits. They are essential components in Bitmain’s Antminer Hydro series like the S21 XP Hyd and in larger-scale immersion setups.
D
Decentralization
The distribution of power, control, and resources across many independent participants rather than concentrating them in a single entity. In Bitcoin mining, decentralization means spreading hashrate across many independent miners and pools so that no single operator can censor transactions or attack the network. Home mining, open-source hardware, Stratum V2, and pool diversity all contribute to mining decentralization. D-Central’s mission is the decentralization of every layer of Bitcoin mining — and every Bitaxe and Nerdminer we ship advances that goal.
DATUM Protocol
A mining protocol developed by OCEAN Pool that gives individual miners the ability to construct their own block templates rather than blindly hashing templates provided by the pool. DATUM (Decentralized Alternative Templates for Universal Mining) advances the goals of Stratum V2’s job negotiation by providing a practical, deployable implementation. By allowing miners to choose which transactions go into blocks, DATUM helps resist mining censorship and furthers Bitcoin’s decentralization. Learn more in our OCEAN Pool guide.
Difficulty
A protocol-level value that determines how hard it is to find a valid block hash. Bitcoin’s difficulty is expressed as a number that sets the target threshold — the lower the target, the harder it is to find a qualifying hash, and the higher the difficulty number. Difficulty exists to ensure that blocks are found approximately every 10 minutes regardless of how much total hashrate is on the network. See also: Difficulty Adjustment, Network Difficulty.
Difficulty Adjustment
The automatic recalibration of Bitcoin’s mining difficulty that occurs every 2,016 blocks (approximately every two weeks). If blocks were found faster than the 10-minute target during the previous period, difficulty increases. If blocks were slower, difficulty decreases. This self-regulating mechanism is one of Bitcoin’s most elegant engineering features — it ensures the network remains functional whether total hashrate doubles or drops by half. Miners must plan for difficulty adjustments when calculating profitability.
Dust
A tiny amount of bitcoin in a UTXO that is worth less than the transaction fee required to spend it, making it economically unspendable. The exact dust threshold depends on current fee rates. Dust is relevant to miners because mining pool payouts below a certain threshold may accumulate dust in your wallet. Understanding UTXO management helps miners avoid accumulating unspendable outputs over time, particularly when receiving frequent small pool payouts.
E
Efficiency (J/TH)
The most important metric for comparing mining hardware, measured in joules per terahash (J/TH). It tells you how much energy a miner consumes to produce one terahash of computational output. Lower J/TH means better efficiency. For example, the Antminer S21 Pro operates at approximately 15 J/TH, while an older S9 runs at roughly 98 J/TH. After every halving, efficiency becomes the primary survival metric — inefficient machines get shut off first. See also: J/TH. Use our mining profitability calculator to model efficiency versus electricity cost.
EH/s (Exahashes per Second)
A unit of hashrate equal to one quintillion (10^18) hashes per second, or 1,000 PH/s. EH/s is the current standard unit for measuring the total Bitcoin network hashrate. As of early 2026, total network hashrate exceeds 800 EH/s and continues climbing. Large mining companies and major pools are also measured in EH/s. For individual miners, EH/s provides context for understanding just how competitive the mining landscape is.
Epoch
In Bitcoin mining, an epoch refers to the 2,016-block period between difficulty adjustments. Each epoch lasts approximately two weeks if blocks are found on the 10-minute average schedule. Some miners and analysts also use “epoch” more loosely to refer to halving cycles (the ~4-year period between halvings). Context determines which meaning applies. In the DAG-based mining context (Ethereum-era), epoch had a different technical meaning related to dataset size.
Extranonce
An additional field in the coinbase transaction that miners can modify to expand the range of possible block header hashes beyond what the 32-bit nonce field alone provides. Modern ASIC miners can exhaust the entire 4-billion nonce range in under a second, so the extranonce gives them additional space to search. The mining pool typically assigns each connected worker a unique extranonce range, which is also how pools avoid duplicate work across miners.
F
F2Pool
One of the oldest and largest Bitcoin mining pools, founded in 2013 in China. F2Pool (also known as Discus Fish) has consistently ranked among the top pools by hashrate share. It supports multiple payout methods including PPS+ and has been both praised for its longevity and criticized for transaction filtering decisions. For a comparison of all major pools, see our best mining pools guide.
Fan Speed
The rotational speed of the cooling fans in an air-cooled ASIC miner, typically measured in RPM (revolutions per minute) and controlled by the firmware as a percentage of maximum. Fan speed directly affects both cooling performance and noise output. Most stock Antminers run fans at 100% speed, generating significant noise. Custom firmware allows fan speed control, and home miners often replace stock fans with quieter alternatives like Noctua models. See our noise reduction guide for fan modification options.
Firmware
The software embedded on an ASIC miner’s control board that manages every aspect of its operation — from chip initialization and pool communication to temperature monitoring and fan control. Stock firmware ships from the manufacturer, but third-party options like Braiins OS+, VNish, and LuxOS unlock features like auto-tuning, undervolting, and advanced telemetry. For Bitaxe miners, AxeOS is the standard firmware. Visit our firmware download center or read the firmware update guide.
FPPS (Full Pay Per Share)
A mining pool payout method that pays miners for every valid share submitted, including an estimate of the transaction fees from the blocks the pool mines. FPPS provides the most predictable income stream for miners — you get paid whether the pool actually finds a block or not. The pool absorbs all variance risk. The trade-off is higher pool fees compared to methods like PPLNS. See our pool vs solo mining guide for a full payout method comparison.
Full Node
A computer running Bitcoin software that independently validates every transaction and block against the full set of consensus rules, without trusting any third party. Running a full node is the ultimate expression of Bitcoin sovereignty — your node is your vote on which version of the Bitcoin rules you accept. Many home miners run a full node alongside their mining hardware, and protocols like Stratum V2 allow miners to construct their own block templates using their node, further decentralizing the network.
G
GH/s (Gigahashes per Second)
A unit of hashrate equal to one billion (10^9) hashes per second. GH/s is the typical performance range for small open-source miners. A Bitaxe Supra running a single BM1366 chip produces roughly 500-700 GH/s, while a Nerdminer operates in the low hundreds of KH/s. See the full hashrate scale: KH/s → MH/s → GH/s → TH/s → PH/s → ZH/s.
Goldshell
A mining hardware manufacturer known for producing compact, home-friendly ASIC miners — particularly for altcoin algorithms like Scrypt, Kadena, and Handshake. Goldshell’s “Mini” and “Box” series popularized the concept of quiet, low-power miners that sit on a desk. While not a major player in SHA-256 Bitcoin mining, Goldshell demonstrated the home mining market demand that products like the Bitaxe now serve with a Bitcoin-native, open-source approach.
GPU Mining
Using graphics processing units (GPUs) to mine cryptocurrency. GPU mining was viable for Bitcoin in the early years (2009-2012) before ASICs made it obsolete by delivering orders of magnitude more hashrate per watt. Today, GPUs are irrelevant for Bitcoin mining but remain used for other proof-of-work algorithms. The transition from GPU to ASIC mining was a pivotal moment in Bitcoin’s history, dramatically raising the barrier to entry — which is exactly why projects like Bitaxe matter, bringing solo mining back to the individual.
H
Halving
See Bitcoin Halving.
Hash Function
A mathematical function that takes input data of any size and produces a fixed-size output (called a hash or digest). Bitcoin uses the SHA-256 hash function, which produces a 256-bit output. Hash functions are one-way: given a hash, you cannot work backward to find the input. They are also deterministic — the same input always produces the same hash. Bitcoin mining is essentially a massive, parallelized brute-force search for an input that produces a hash below a certain target value.
Hashboard
The PCB (printed circuit board) inside an ASIC miner that contains the array of ASIC chips performing the actual mining computation. A typical Antminer contains three hashboards, each populated with dozens to hundreds of chips connected in a voltage domain chain. Hashboard failures — dead chips, damaged traces, bad solder joints — are the most common reason ASIC miners lose performance or go offline. D-Central performs hashboard-level repairs including chip replacement. Learn more in our hashboard guide.
Hashrate
The speed at which a mining device or the entire Bitcoin network computes SHA-256 hashes, measured in hashes per second. Hashrate is the fundamental measure of mining power. A higher hashrate means more chances per second of finding a valid block. Individual miner hashrate is measured in TH/s (terahashes) for commercial ASICs or GH/s for devices like Bitaxe. The total network hashrate is measured in PH/s or ZH/s. Use our mining profitability calculator to model your hashrate against current difficulty.
Heat Recovery
The practice of capturing and reusing the thermal energy produced by ASIC miners instead of exhausting it as waste. Since mining hardware converts nearly 100% of its electrical input into heat, that energy can be redirected for home heating, water heating, greenhouse warming, pool heating, grain drying, and dozens of other applications. Heat recovery transforms mining from a “pure cost” energy model into a dual-purpose system. D-Central has documented 25+ real-world heat recovery applications and builds purpose-built space heater configurations.
Heatbit
A commercial product that packages a Bitcoin ASIC miner inside a consumer-grade space heater enclosure, marketed as a “heater that mines Bitcoin.” Heatbit was one of the first retail products to market the dual-purpose mining concept to non-technical consumers. D-Central takes a more modular, open approach to the same concept with our Bitcoin Space Heater lineup, which gives miners more control over hardware selection, maintenance, and upgrades. Read our Heatbit review for an honest assessment.
Home Mining
The practice of running Bitcoin mining hardware in a residential setting — a basement, garage, spare room, or even a living space when using the miner as a space heater. Home mining is a core pillar of Bitcoin’s decentralization because it distributes hashrate away from industrial data centers. Challenges include noise management, heat dissipation, electrical capacity, and optimizing for household power rates. D-Central exists to make home mining accessible. Start with our beginner’s guide or explore quiet miners for home use.
Hydro Cooling
A cooling method where liquid coolant flows through channels or cold plates in direct contact with ASIC chips, carrying heat away far more efficiently than air cooling. Bitmain’s “Hyd” series (e.g., S19 XP Hyd, S21 XP Hyd) are factory-designed hydro-cooled units. Hydro cooling enables higher chip frequencies and greater hashrate density per rack unit, but requires a CDU, plumbing infrastructure, and careful leak prevention. See also: Immersion Cooling. Read our S21 XP Hyd review.
I
Immersion Cooling
A cooling technique where mining hardware is fully submerged in a non-conductive dielectric fluid (typically engineered mineral oil or synthetic coolants). The fluid absorbs heat directly from all components and transfers it to a heat exchanger. Immersion cooling eliminates fans entirely, dramatically reduces noise, enables higher overclocking headroom, and extends hardware lifespan by protecting components from dust and humidity. It is increasingly popular for home miners seeking silent operation. Read our complete immersion cooling DIY guide.
Innosilicon
A Chinese semiconductor and mining hardware company that manufactures ASIC miners across multiple algorithms. Their SHA-256 miners (T2, T3 series) competed with Bitmain’s Antminer lineup, and their Ethereum miners (A10, A11) were widely deployed. Innosilicon miners are less common than Antminers but still appear in the repair market. D-Central provides Innosilicon repair services for the T1, T2, T2T, T3, A4+, and A10 models.
J
J/TH (Joules per Terahash)
The standard unit for measuring ASIC mining efficiency. J/TH expresses how many joules of electrical energy are consumed to produce one terahash of SHA-256 computation. A machine rated at 20 J/TH uses 20 joules of energy for every trillion hashes it computes. Lower is better. Modern flagship miners like the Antminer S21 Pro achieve around 15 J/TH, while older machines like the S9 consume roughly 98 J/TH. This single metric determines whether a miner is profitable at a given electricity rate — it is the number that matters most when choosing hardware. Model your scenarios with our profitability calculator.
K
KH/s (Kilohashes per Second)
A unit of hashrate equal to one thousand (10^3) hashes per second. KH/s is the performance range of the smallest mining devices, such as the Nerdminer, which operates in the tens to hundreds of KH/s range. At this hashrate, mining is purely educational or for lottery mining — the odds of finding a block are astronomically low, but non-zero. See the full scale: KH/s → MH/s → GH/s → TH/s → PH/s → ZH/s.
Kernel Log
The system-level diagnostic output from an ASIC miner’s operating system, accessible via SSH or the web interface on some firmware. Kernel logs contain critical information about chip initialization, voltage regulation, temperature readings, error states, and hashboard communication. Reading kernel logs is an essential skill for diagnosing miner problems — they reveal issues like chip failures, power delivery problems, and firmware crashes that the standard dashboard may not surface. Our repair technicians rely heavily on kernel log analysis.
L
Loki Kit
A D-Central custom modification kit that converts a standard Antminer into a compact, home-friendly configuration. The Loki Edition reduces the form factor and can be adapted for dual-purpose mining and heating applications. Like the Slim Edition and Pivotal Edition, the Loki Kit represents D-Central’s Mining Hacker philosophy — taking industrial-grade mining technology and hacking it to work for home miners. These custom builds are unique to D-Central.
Lottery Mining
A colloquial term for solo mining with a small device like a Bitaxe or Nerdminer, where the odds of finding a full block reward are extremely low but the potential payoff is enormous. Much like buying a lottery ticket, the expected value per hash is the same as pool mining — but the payout distribution is all-or-nothing. You either find a full block (currently worth 3.125 BTC plus fees) or you earn nothing. The Bitaxe community has tracked multiple solo block wins, proving it can happen. Read our philosophy of lottery mining.
LuxOS
A third-party firmware for Antminer hardware developed by Luxor Technology. LuxOS offers features including per-chip tuning, curtailment scheduling, fleet management APIs, and detailed performance analytics. It competes with Braiins OS+ and VNish as one of the three major aftermarket firmware options for Antminer machines. Read our dedicated LuxOS guide and three-way firmware comparison.
M
Mempool
The memory pool of unconfirmed Bitcoin transactions waiting to be included in a block. Each Bitcoin node maintains its own mempool. When you send a Bitcoin transaction, it enters the mempool and waits until a miner selects it for inclusion in a block. Miners typically prioritize transactions with higher fee rates (sats/vByte). The mempool size fluctuates based on network activity — during high congestion, the mempool grows and fees spike. Miners benefit from full mempools because total transaction fees per block increase.
Mesh Stand (Bitaxe Mesh Stand)
A 3D-printed or manufactured open-mesh mounting stand designed for Bitaxe miners. The mesh stand positions the Bitaxe vertically for optimal airflow and cooling while keeping the device stable and accessible. D-Central created the original Bitaxe Mesh Stand — the first company to design and manufacture it — and it has since become a standard accessory in the Bitaxe ecosystem. Browse our Bitaxe accessories guide for stand options and other accessories.
Merkle Root
A single hash value that cryptographically summarizes all transactions in a Bitcoin block. It sits in the block header and is computed by repeatedly hashing pairs of transaction hashes until one root hash remains (a binary tree structure called a Merkle tree). The Merkle root allows anyone to efficiently verify whether a specific transaction is included in a block without downloading every transaction. When miners hash the block header, the Merkle root is one of the fields being hashed alongside the nonce, timestamp, and previous block hash.
MH/s (Megahashes per Second)
A unit of hashrate equal to one million (10^6) hashes per second. MH/s was the standard performance range during Bitcoin’s GPU mining era (2010-2012) and is now relevant for some very small mining devices. In the modern ASIC mining landscape, even the smallest dedicated miners like NerdAxe devices operate in the GH/s range, making MH/s largely a historical reference for Bitcoin SHA-256 mining.
Mining Hacker
D-Central’s core identity and philosophy. A Mining Hacker takes institutional-grade mining technology — designed for warehouse-scale operations with 240V three-phase power and industrial cooling — and hacks it to run in a home, on residential power, silently, and often as a dual-purpose heater. Mining Hackers reflash firmware, replace fans, build custom shrouds, modify power delivery, and create entirely new form factors. D-Central embodies this ethos with products like the Slim Edition, Space Heaters, and extensive open-source miner lineup.
Mining Pool
A service that combines the hashrate of many individual miners to find blocks more frequently and split the block reward proportionally among participants. Without pools, a small miner might wait decades between block finds. Pools smooth out the variance by providing regular, predictable payouts. Major Bitcoin pools include Foundry, Antpool, ViaBTC, F2Pool, and OCEAN. The choice of pool involves trade-offs around fees, payout methods, decentralization principles, and geographic latency. See our comprehensive mining pools comparison.
N
NerdAxe
An open-source Bitcoin mining device in the Nerd family of miners, featuring a single BM1397 ASIC chip. The NerdAxe bridges the gap between the educational Nerdminer (ESP32-based, KH/s range) and the more powerful Bitaxe (BM1366/BM1370, hundreds of GH/s range). It offers a meaningful solo mining hashrate while remaining affordable and simple to assemble. D-Central carries the NerdAxe and has a complete NerdAxe setup guide. See our Bitaxe vs NerdAxe comparison.
Nerdminer
An entry-level, open-source Bitcoin solo mining device built on an ESP32 microcontroller with a tiny screen. The Nerdminer produces hashrate in the KH/s range — negligible by mining standards — but serves as an educational tool, a conversation piece, and a philosophical statement about the right of every Bitcoiner to participate in securing the network. It is the most accessible entry point into the world of Bitcoin mining hardware. D-Central stocks Nerdminers and provides a complete setup guide.
NerdNOS
An open-source mining firmware and device platform based on the ESP32-S3 microcontroller, offering improved performance over the original Nerdminer. NerdNOS provides better hash computation efficiency and a more capable hardware platform while maintaining the open-source, accessible spirit of the Nerd mining family. It sits between the Nerdminer and NerdAxe in the performance hierarchy. See our NerdNOS setup guide.
NerdQAxe
A quad-chip open-source Bitcoin mining device that packs four BM1397 ASIC chips onto a single board, producing significantly more hashrate than a single-chip NerdAxe. The NerdQAxe (and its enhanced NerdQAxe++ variant) offers a compelling middle ground in the open-source mining hierarchy — substantially more hashrate than entry-level devices while remaining far more affordable and compact than commercial ASICs. D-Central carries the NerdQAxe and provides a NerdQAxe++ setup guide and overclocking guide.
Network Difficulty
The current difficulty value active on the Bitcoin network, which determines the target that block hashes must fall below. Network difficulty is a direct reflection of total network hashrate — as more miners join and hashrate rises, difficulty increases to maintain the 10-minute block interval. As of early 2026, Bitcoin’s network difficulty is at all-time highs. The difficulty number is critical for calculating solo mining probability and mining profitability.
Noctua
An Austrian manufacturer of premium computer cooling fans, widely regarded as producing the quietest and most reliable fans available. In the home mining community, replacing an ASIC miner’s loud stock fans with Noctua fans is one of the most popular noise reduction modifications. Noctua’s NF-A12x25 and NF-A14 models are commonly used, though they typically provide less airflow than stock industrial fans, which may require underclocking to stay within thermal limits. See our noise reduction guide for fan swap instructions.
Nonce
A 32-bit number in the Bitcoin block header that miners increment (or randomize) with each hash attempt. The nonce is the primary variable that miners manipulate when searching for a valid block hash. By changing the nonce and re-hashing the block header, miners produce different hash outputs, searching for one that falls below the current target. Since modern ASICs can exhaust the entire 4-billion nonce range in under a second, the extranonce and timestamp fields provide additional search space.
O
OCEAN Pool
A Bitcoin mining pool co-founded by Jack Dorsey and Luke Dashjr, built on principles of transparency, non-custodial payouts, and miner sovereignty. OCEAN stands apart from conventional pools by implementing the DATUM protocol, which allows miners to construct their own block templates — a significant step toward mining decentralization. OCEAN also provides non-custodial coinbase payouts directly to miners’ wallets and operates with a transparent fee structure. Read our complete OCEAN Pool review and setup guide.
Open-Source Mining
The philosophy and practice of building Bitcoin mining hardware using publicly available, open-source designs that anyone can manufacture, modify, and improve. The open-source mining movement — led by projects like Bitaxe, NerdAxe, NerdQAxe, and others — represents a direct challenge to the closed, proprietary approach of major manufacturers. D-Central is a pioneer in this space, stocking and supporting the full range of open-source mining hardware. See our complete comparison.
Overclocking
Running ASIC chips at higher clock frequencies and/or voltages than the manufacturer’s default settings to increase hashrate. Overclocking produces more hashes per second but at the cost of increased power consumption, higher heat output, and reduced efficiency (higher J/TH). It may also accelerate chip degradation. Overclocking is popular in the Bitaxe community, where pushing a Gamma from 1.2 TH/s to 2+ TH/s is a common goal. D-Central has detailed overclocking guides for Bitaxe and NerdQAxe models.
P
PH/s (Petahashes per Second)
A unit of hashrate equal to one quadrillion (10^15) hashes per second, or 1,000 TH/s. PH/s is the scale at which medium-to-large mining operations and individual mining pools are measured. A single Antminer S21 Pro produces approximately 0.234 PH/s (234 TH/s). The total Bitcoin network hashrate is measured in hundreds of thousands of PH/s, often expressed as ZH/s.
Pool Fee
The percentage of mining earnings that a mining pool retains as payment for operating the pool infrastructure. Pool fees typically range from 0% to 4%, depending on the pool and payout method. FPPS pools tend to charge higher fees (2-4%) because the pool absorbs variance risk. PPLNS pools generally charge lower fees (0-2%). Solo mining pools like CKPool charge minimal or zero fees. Always factor pool fees into your profitability calculations.
PPLNS (Pay Per Last N Shares)
A mining pool payout method that distributes the block reward proportionally among miners based on the number of shares they contributed during a recent window of N shares. Unlike PPS, miners only get paid when the pool actually finds a block. This means higher variance in payouts but typically lower pool fees. PPLNS rewards loyal miners who maintain consistent hashrate and penalizes pool-hoppers. See our pool vs solo mining guide for payout comparisons.
PPS (Pay Per Share)
A mining pool payout method that pays miners a fixed amount for every valid share they submit, regardless of whether the pool finds a block. PPS provides the most stable, predictable income — every share has a guaranteed value based on the current difficulty and block reward. The pool operator absorbs all luck variance, which is why PPS pools charge higher fees. PPS+ is a common variant that also includes estimated transaction fees in the per-share payment. See also: FPPS.
Proof of Work (PoW)
The consensus mechanism that secures the Bitcoin network. Proof of Work requires miners to expend real computational energy — performing trillions of SHA-256 hash operations — to find a valid block. This energy expenditure is what makes Bitcoin tamper-proof: to rewrite history, an attacker would need to redo all the work, which is prohibitively expensive. PoW is not a “waste” of energy — it is the thermodynamic anchor that gives Bitcoin its security and immutability. Every hash you produce, whether from an Antminer fleet or a single Bitaxe, strengthens this security.
PSU (Power Supply Unit)
The component that converts AC mains electricity into the DC voltage required by an ASIC miner’s hashboards. Bitmain’s APW series (APW7, APW9, APW12) are the most common mining PSUs. The PSU must provide sufficient wattage for the miner’s power draw plus headroom — undersized PSUs cause instability and shutdowns. PSU failures are a common repair issue, and D-Central provides diagnostics and repair for all major mining PSUs. See our APW12 repair guide and APW9 repair guide. Browse replacement power supplies in our shop.
Q
QR Code Wallet
A Bitcoin wallet address encoded as a QR code for easy scanning and payment. In the mining context, QR code wallets are commonly used to configure payout addresses on mining devices. AxeOS and most mining pool dashboards support entering your wallet address where mining rewards will be sent. For solo miners, the wallet address configured in your miner is where the full block reward will land if your device finds a valid block.
R
Reject Rate
The percentage of shares submitted by your miner that the pool rejects as invalid. Common causes include stale shares (submitted after a new block was found), hardware errors producing incorrect hashes, network latency, and overclocking instability. A healthy reject rate is below 1-2%. Rates consistently above 3-5% indicate a problem — typically unstable overclocking settings, failing ASIC chips, poor network connectivity, or high pool latency. Monitoring reject rate is essential for optimizing your miner’s effective hashrate.
Reward
See Block Reward.
RPC (Remote Procedure Call)
A communication protocol that allows software to request actions or data from another program, typically over a network. In Bitcoin mining, RPC interfaces are used in two main contexts: (1) Bitcoin Core’s RPC API, which allows miners running a full node to retrieve block templates and submit found blocks, and (2) ASIC miner management APIs that allow fleet management software to query status, change settings, and restart miners remotely. RPC access is essential for advanced mining operations and firmware like LuxOS provides extensive RPC endpoints.
S
Share
A unit of work submitted by a miner to a mining pool as proof that the miner is actively hashing. A share is a hash that meets a lower difficulty threshold set by the pool — much easier to find than a full block hash, but statistically representative of the miner’s contribution. The pool uses shares to fairly distribute the block reward when a block is found. Occasionally, a share also meets the full network difficulty threshold, in which case it is a valid block. See also: Reject Rate, Stale Share.
SHA-256
The cryptographic hash function that Bitcoin uses for its Proof of Work mining algorithm. SHA-256 (Secure Hash Algorithm, 256-bit) takes any input data and produces a unique, fixed-length 256-bit (32-byte) output. Bitcoin actually applies SHA-256 twice (double-SHA-256) to block headers. Every Bitcoin ASIC miner — from a warehouse-filling Antminer rack to a tiny Bitaxe on your desk — is computing SHA-256 hashes billions of times per second, searching for the one hash that wins the next block.
Shroud
A duct or enclosure attached to the intake or exhaust of an ASIC miner to direct airflow. Shrouds are essential for home mining setups where you need to channel hot exhaust air into a specific path — out a window, into ductwork, or into a room you want to heat. Without a shroud, hot air recirculates and the miner overheats. D-Central designs and sells universal shrouds and duct adapters that fit standard ASIC miner form factors. See our space heater assembly guide for installation instructions.
Slim Edition (Antminer Slim Edition)
A D-Central custom modification of standard Antminer hardware, redesigned into a compact form factor optimized for home mining on residential 120V (North American standard) or 110V power. The Slim Edition removes one or two hashboards from a standard three-hashboard Antminer, reducing power consumption to household circuit levels while maintaining mining capability. This is a signature Mining Hacker product — taking industrial equipment and engineering it for the home. Read about the Antminer Slim Edition.
Solo Mining
Mining Bitcoin independently without joining a mining pool. Solo miners submit work directly to the network (or through a solo-mode pool like CKPool) and receive the entire block reward if they find a valid block. The trade-off is extreme variance: a solo miner might wait days, months, or years between payouts — or find one tomorrow. Solo mining is philosophically aligned with Bitcoin’s decentralization mission and is the driving purpose behind devices like the Bitaxe. Read our comprehensive solo mining guide or calculate your odds with our solo mining probability calculator.
Space Heater (Bitcoin Space Heater)
An ASIC miner repurposed or purpose-built to serve as a home heating appliance while simultaneously mining Bitcoin. Since miners convert virtually 100% of their electrical input into heat, a 1,500W miner produces the same heat as a 1,500W electric space heater — except it also generates bitcoin. This dual-purpose approach effectively subsidizes your heating costs with mining revenue. D-Central pioneered multiple space heater configurations using Antminer S9, S17, S19, and L3+ hardware. Use our BTU calculator to size your setup, and read the space heater vs electric heater cost comparison.
Stale Share
A share submitted to a mining pool after the work it was based on has already been superseded — typically because a new block was found on the network while the share was being computed or transmitted. Stale shares are rejected by the pool and do not count toward your payout. A high stale rate can indicate network latency between your miner and the pool, or that your mining device is slow to accept new work. Switching to a geographically closer pool endpoint often reduces stale shares.
Stratum V2
The next-generation mining communication protocol designed to replace the original Stratum protocol (V1) that has been the standard since 2012. Stratum V2 introduces encrypted connections (preventing hashrate hijacking), allows miners to construct their own block templates via job negotiation (reducing pool censorship power), and significantly reduces network bandwidth requirements. It represents a major step toward mining decentralization by shifting power from pools back to individual miners. Braiins OS+ was the first firmware to implement Stratum V2. Read our in-depth Stratum V2 guide.
T
Target
A 256-bit number that a block’s hash must be less than or equal to for the block to be considered valid. The target is derived from the current difficulty — higher difficulty means a lower target, requiring more leading zeros in the hash. When a miner finds a nonce that produces a hash below the target, they have successfully mined a block. The target is recalculated every epoch (2,016 blocks) during the difficulty adjustment.
TH/s (Terahashes per Second)
A unit of hashrate equal to one trillion (10^12) hashes per second. TH/s is the standard measurement for modern commercial ASIC miners. The Antminer S21 produces approximately 200 TH/s, the S21 Pro delivers 234 TH/s, and a Bitaxe Gamma can reach roughly 1-2 TH/s with overclocking. When evaluating miners, always consider TH/s alongside J/TH efficiency — a high hashrate is meaningless if the power cost exceeds the mining revenue. Compare miners with our ASIC comparison tool.
Thermal Paste (Thermal Compound)
A heat-conductive compound applied between ASIC chips and their heatsinks to maximize heat transfer. Over time, thermal paste dries out and cracks, degrading thermal conductivity and causing chips to overheat, throttle, or fail. Replacing dried thermal paste is one of the most common and cost-effective ASIC maintenance tasks, often restoring lost hashrate and improving chip longevity. Quality thermal paste is essential during any repair that involves removing heatsinks from hashboards.
TIDES
Transparent Index of Distinct Extended Shares — the payout method used by OCEAN Pool. TIDES is designed to be fully transparent and auditable, tracking each miner’s contributed shares with cryptographic proof. It functions similarly to PPLNS but with enhanced transparency features that align with OCEAN’s commitment to non-custodial, verifiable pool operations. TIDES payouts go directly to miners’ wallets via the coinbase transaction. Learn more in our OCEAN Pool guide.
Transaction Fee
The amount of bitcoin that a sender includes in a transaction as payment to the miner who includes it in a block. Transaction fees are calculated based on the transaction’s data size (measured in virtual bytes) and the current fee market. Fees incentivize miners to include transactions in their blocks and will become an increasingly important component of the block reward as the block subsidy continues halving toward zero. During periods of high network congestion, transaction fees can exceed the block subsidy, creating significant bonus revenue for miners.
U
Underclocking
Running ASIC chips at lower clock frequencies than the manufacturer’s default to reduce power consumption, heat output, and noise. Underclocking decreases hashrate but often improves efficiency (J/TH) because power consumption drops faster than hashrate at lower frequencies. This is a key technique for home miners who need to stay within a 15A or 20A residential circuit, reduce noise for fan swaps, or limit heat output in summer months. See also: Undervolting.
Undervolting
Reducing the core voltage supplied to ASIC chips below the manufacturer’s default setting. Undervolting is one of the most effective ways to improve mining efficiency, as it reduces power consumption (which scales roughly with the square of voltage) while maintaining most of the hashrate. It is the go-to optimization for home miners seeking the best J/TH at household power limits. Third-party firmware like Braiins OS+, VNish, and LuxOS all support undervolting. Read our comprehensive undervolting guide.
UTXO (Unspent Transaction Output)
A discrete chunk of bitcoin that exists as an output of a previous transaction and has not yet been spent as an input to a new transaction. The Bitcoin ledger is not a balance-based system — instead, your “balance” is the sum of all UTXOs your wallet controls. For miners, UTXO management matters because frequent small pool payouts create many small UTXOs that may become dust when fees rise. Consolidating UTXOs during low-fee periods is a recommended practice for active miners.
V
Variance
The statistical fluctuation in mining income caused by the probabilistic nature of finding blocks. Because mining is essentially a random process (each hash has an independent, tiny probability of being valid), actual results will deviate from the mathematical expected value over short periods. High variance means unpredictable payouts — you might find two blocks in one day and then none for a month. Mining pools reduce variance by combining hashrate; solo mining has maximum variance. Variance is not luck — over sufficient time, actual results converge to expected values.
VNish
A popular third-party firmware for Antminer and Whatsminer ASIC miners, developed by a Russian-origin team. VNish offers auto-tuning, manual per-chip voltage control, fan speed management, immersion mode, and a user-friendly web interface. It is one of the three major aftermarket firmware choices alongside Braiins OS+ and LuxOS. VNish is known for aggressive tuning capabilities that squeeze maximum performance from hardware. Read our VNish firmware guide and firmware comparison.
W
Watt (W)
The standard unit of electrical power, measuring the rate of energy consumption. In mining, watts (W) and kilowatts (kW) quantify how much electricity a miner draws from the wall. A typical modern ASIC miner consumes 3,000-5,000W (3-5 kW), while a Bitaxe draws only 5-15W. Watts are essential for calculating electricity costs (multiply watts by hours and your rate per kWh), sizing your electrical circuit, and determining BTU heat output. Use our power cost calculator and check our 120V mining guide for residential power planning.
Whatsminer
A line of ASIC miners manufactured by MicroBT, the second-largest Bitcoin mining hardware manufacturer after Bitmain. Whatsminer models (M30, M50, M60 series) are known for robust build quality and competitive efficiency. They compete directly with Bitmain’s Antminer lineup for market share. D-Central repairs Whatsminer hardware across all models and has published a Whatsminer M30S repair guide. See our Whatsminer vs Antminer comparison and complete Whatsminer guide.
Worker
An identifier assigned to an individual mining device or group of devices within a mining pool account. When you configure your miner’s pool settings, you specify a worker name (typically in the format username.workername). Worker names allow you to track the performance, hashrate, and reject rate of each miner independently on your pool dashboard. This is essential for fleet management — quickly identifying which machine is underperforming or offline.
Z
ZH/s (Zettahashes per Second)
A unit of hashrate equal to one sextillion (10^21) hashes per second, or one million PH/s. ZH/s is the scale at which total Bitcoin network hashrate is now measured. As of early 2026, Bitcoin’s total network hashrate fluctuates in the range of hundreds of EH/s approaching the ZH/s threshold — a staggering amount of computational power securing the network. This number represents the combined output of every ASIC miner on the planet, from industrial facilities to solo Bitaxe miners. Every hash counts.
Keep Learning
This glossary is a living document — we update it as new technology, protocols, and hardware enter the Bitcoin mining ecosystem. If you are just getting started, head to our Complete Beginner’s Guide to Bitcoin Mining for a structured walkthrough. Ready to buy your first miner? Explore our open-source miners, browse the full D-Central shop, or use our mining profitability calculator to crunch the numbers.
Have a term you think we should add? Reach out and let us know. We are Mining Hackers — and the dictionary keeps growing.