Definition
The CERN Open Hardware Licence (CERN-OHL) is a legal tool developed by CERN to promote collaboration among hardware designers and protect the freedom to use, study, modify, share, and distribute hardware designs and the products built from them. Software licenses such as the GPL are written for code; CERN-OHL is purpose-built for the schematics, board layouts, mechanical drawings, and other "source" of physical hardware.
The three variants of version 2
CERN-OHL v2 comes in three options that mirror the software licensing spectrum. CERN-OHL-P (Permissive) imposes minimal obligations and is the most flexible. CERN-OHL-W (Weakly Reciprocal) requires that changes to the licensed design be shared, but allows it to be combined with separately designed components under other terms. CERN-OHL-S (Strongly Reciprocal) is the most protective: any product or derivative that incorporates the design must make its complete design source available under the same license.
Why it matters for open mining hardware
Open ASIC carrier boards, Bitaxe-style single-chip miners, controller boards, and PSU breakout designs increasingly publish their hardware source under CERN-OHL. The reciprocal variants ensure that improvements to a community board design flow back to the community, just as copyleft does for software.
When choosing a variant, designers weigh the same trade-off seen in software: broad reuse under a permissive variant, or guaranteed downstream openness under a reciprocal one.
In Simple Terms
The CERN Open Hardware Licence (CERN-OHL) is a legal tool developed by CERN to promote collaboration among hardware designers and protect the freedom to use,…