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Linux is a family of open source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991 by Linus Torvalds. Linux is typically packaged in a Linux distribution (or distro for short).

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How is RISC-V better than arm for Linux? (programming.dev)

submitted 3 months ago* (last edited 3 months ago) by [email protected] to c/[email protected]

42 comments fedilink hide all child comments

Help me understand this better.

From what I have read online, since arm just licenses their ISA and each vendor's CPU design can differ vastly from one another unlike x86 which is standard and only between amd and Intel. So the Linux support is hit or miss for arm CPUs and is dependent on vendor.

How is RISC-V better at this?. Now since it is open source, there may not be even some standard ISA like arm-v8. Isn't it even fragmented and harder to support all different type CPUs?

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[–] [email protected] 9 points 3 months ago (4 children)

How did AMD get the rights to build these CPUs? It is the only competitor it seems.

[–] [email protected] 33 points 3 months ago (3 children)

TL;DR: While Intel had their heads shoved up their ass making the Itanium architecture, AMD made a 64-bit variant of x86 that was backward compatible with the older x86 ISA. Technology moved on, and amd64 was adopted while Intel kept trying and failing to push their binary-incompatible architecture.

Eventually, Intel had to give up and adopt AMD's amd64 ISA. In exchange for letting them use it, Intel lets AMD use the older x86 ISA.

[–] [email protected] 42 points 3 months ago (1 children)

AMD were already using the x86 ISA long before amd64.

https://en.m.wikipedia.org/wiki/AMD

Intel had introduced the first x86 microprocessors in 1978.[51] In 1981, IBM created its PC, and wanted Intel's x86 processors, but only under the condition that Intel also provide a second-source manufacturer for its patented x86 microprocessors.[12] Intel and AMD entered into a 10-year technology exchange agreement

AMD were also second source for some other Intel logic chips before that deal.

[–] [email protected] 14 points 3 months ago* (last edited 3 months ago)

I was only going for explaining why AMD still continues to have the license to the x86 instruction set in modern times, but I appreciate the added historical context to explain to others how they originally had the rights to use it.

[–] [email protected] 4 points 3 months ago

Itanium also failed miserably in performance and everything else it set out to deliver. While being ridiculously expensive.

[–] [email protected] 2 points 3 months ago

Crazy!

[–] [email protected] 22 points 3 months ago

VIA also built x86 CPUs for some time, they have a license as well; the issue with modern x86_64 is though that basically, you need licenses from both AMD and Intel. They do have a cross-license agreement, but there's no single point of contact for all licenses for a modern x86 CPU.

[–] [email protected] 12 points 3 months ago

To sell into the US government in the 70s you had to ensure your parts could be sourced from a second company. That way, if you had supply problems, the government would just got to the second source.

AMD was a second source for the 8086.

[–] [email protected] 2 points 3 months ago* (last edited 3 months ago)

~~They reverse-engineered them~~

Edit: Huh, apparently I misremembered