63
ELI5: What is RISC-V?
(sh.itjust.works)
All about open source! Feel free to ask questions, and share news, and interesting stuff!
Community icon from opensource.org, but we are not affiliated with them.
A CPU instruction set that is governed by the RISC V International organization, a nonprofit organization which also holds all the RISC V related trademarks.
It has nothing to do with open source really, it is a open standard that anyone can create compatible products for and those products can also be sold commercially.
Really the difference is that the organization verifying your that your CPU correctly follows the instruction set so you can sell it as such, has no profit motive, unlike ARM or Intel/AMD who either outright block any meaningful competition in the case of x86 or want a nice share of the money your gonna make in the case of ARM. Not to mention that ARM and Intel/AMD sell their own CPUs, so there is a big conflict of intressts going on.
Only if you think that open hardware and open software are totally unrelated things, but most open hardware people and open software people think that they are related things.
No, open source means that its public HOW something is done, down to every single line of code (along a lot of other things when it comes to licensing, redistribution, … but thats not the main point)
With a open standard its public WHAT something is doing, but HOW its achieved can be public or not.
To give you a example, HTML is a open standard for displaying Webpages. Somewhere its defined that when a element is found, the browser has to render a button which looks a certain way behaves a certain way when interacting with the mouse, keyboard, javascript, css … . This is WHAT your browser needs to do.
But HOW you do it is up to each browser. Do you use the CPU or GPU to render it? Do you first draw the border, then the text or the other way around? It doesn’t matter to the standard as long as the end result complies with the spec.
With open source browsers like chromium and firefox it is public HOW they are implementing this feature, down every line of code.
With a proprietary browser like Internet Explorer which follows (or rather followed) the same open standard nobody knows HOW they are implementing it. We only know that the end result is adhering to the HTML Standard.
The hardware equivalent it would be someone releasing the exact schematics of for example a RISC V CPU where somebody could see HOW they implement the specifications of the Architecture and where someone could without much hassle go to a Manufacturer and get the chip into production or make modifications.
Yes, but open-specifications doesn't mean open-hardware.
Open specifications may not be sufficient for open hardware, but they are largely necessary. https://simple.wikipedia.org/wiki/Necessary_and_sufficient_conditions
OpenHW Group: CORE-V Family of Open-Source RISC-V Cores
The point is rather that RISC-V is only open-specifications and most available chip designs are not open-source or only partially so in the open-hardware sense.
No one would claim that the Ethernet specifications are open-hardware, yet you see the same (false) claim for RISC-V all the time.
That’s fine, but I’m not making that claim. RISC-V is free of patent & licensing encumbrances as well as copyright ones, which allows for the possibility of open hardware developing on it. Open source software is likewise about patents and other encumbrances, not only copyright.