As a layperson though, how would I be able to tell whether any of this is true? When I have to target platforms as a software developer, the truth is, I’ll do whatever Microsoft and Apple tell me to. By the time Apple is shipping a RISC-V phone I hope to be retired!
> As a layperson though, how would I be able to tell whether any of this is true?
You probably won't ever know. Do you know the architecture of the microcontroller on your first computer's hard drive? I don't.
The stuff that RISC-V will replace first is the low-margin hardware that can be mass-produced by China et. al and exported without license violation. ARM's goose was already cooked in this sense, and even ARM China won't fix it. For IO controllers, ICs and network switches, it's hard to see why manufacturers would stick with higher-margin ARM hardware. If RISC-V cores are cheap, stable and available, you could replace them without the user ever noticing.
> By the time Apple is shipping a RISC-V phone I hope to be retired!
Apple holds a rare Architecture license to the ARM ISA due to their role as a founding partner, and can make original implementations without incurring licensing dues, as they do with the A and M series CPUs. I understand why they would want to switch to homegrown designs instead of licensing ARM reference designs (which they do have to pay for), but why migrate instruction sets too when RISC-V doesn't save them any marginal cost over novel ARM designs that would be binary compatible with the existing firmware?
> Apple holds a rare Architecture license to the ARM ISA due to their role as a founding partner, and can make original implementations without incurring licensing dues
Sorry, the architecture license wasn’t a thing when Arm was founded and there is no way that Arm would hand out free licenses at a later date. It’s just a myth.
"We have entered into a new long-term agreement with Apple that extends beyond 2040, continuing our longstanding relationship of collaboration with Apple and Apple's access to the Arm architecture," - ARM's IPO Document.
I assume they paid something for it, but who knows how much, ARM and Apple have not decided to tell us.
Western Digital announced an open source core ("SweRV") in 2019, so I assume they already use them now that we are a few years on from that announcement.
For any kind of high-level code, "platform" is something like win32 or Android or Qt. The underlying hardware architecture is the compiler/interpreter's problem.
The people dealing with assembly know who they are, but much of that is the sort of work that cares a lot about shaving off a few cents worth of license fee for an embedded device.
For users of general purpose computers this is caused almost entirely by closed-source software. Most of the architecture-specific code is part of the operating system, and by the time you're doing an architecture transition the OS itself runs on the new architecture. The third party applications largely aren't dependent on a specific architecture but they're compiled for one.
With open source you could just recompile for the new architecture. Linux has always run on just about every one under the sun and the user largely can't even tell the difference. But if you don't have the source code you can't do that.
Closed-source systems could avoid this by compiling to bytecode, which is essentially what Android does, so transitioning to RISC-V would be much less trouble there than it would be for e.g. Windows.
