6 ms·

RISC-V is thrown around like if it's an already working CPU but it is not. It is just a document describing an ISA, you can't compare it to Linux, it's a comple

by sweden 9y ago

RISC-V is thrown around like if it's an already working CPU but it is not. It is just a document describing an ISA, you can't compare it to Linux, it's a completely different thing. There are a lot of costs in implementing an ISA and that includes: design, functional verification, physical implementation and software testing. All those steps together will require hundreds and hundreds of engineers, many expensive tools and thousands of man-hours. And once you are done, you will need to find be careful not to violate any patents while shipping your CPU to the end customer. By paying a license fee to ARM, you get all these steps done for you plus with support. Linux is something that you can download from kernel.org, compile overnight and get it booting right away. RISC-V is something that you need to build yourself.

rwmj 9y ago
When I did a presentation on RISC-V last year I counted 6 real implementations (full custom ASICs). Now granted only one or two of those you can buy, the others are research projects, but they do exist and they did produce real silicon. This year we should see a couple of 64 bit implementations, which is when it'll get really interesting. There are of course multiple FPGA implementations (I have one about 2 feet away from me now), but they are very slow.
- eggsome 9y ago
  Is your presentation online?
  - rwmj 9y ago
    No it was a private talk about company strategy.
- sweden 9y ago
  I am aware that they exist but it's not like companies are going to actively invest in devices for the end consumer purely based on RISC-V.
  - sangnoir 9y ago
    From where I'm standing, it looks like you're shifting goalposts: > > RISC-V is thrown around like if it's an already working CPU but it is not (Evidence of existing CPUs provided) > I am aware that they exist but it's not like companies are going to actively invest in devices for the end consumer purely based on RISC-V.
    - sweden 9y ago
      My point is, you can't get those existing CPUs for free.
      - microcolonel 9y ago
        What kind of for free are you talking? The first commercial run RISC-V microcontroller SoC has fully-published RTL, and a company which will support you in adding it to your products (SiFive). Obviously people aren't going to give you the manufactured chips for free, but how close do you want it?
tssva 9y ago
Linux didn't instantly become something you could download from kernel.org, compile overnight and get it booting right away. It took hundreds and hundreds of developers, thousands of man hours, financial investments from a large number of companies worldwide and many many years for Linux to become what it is today. All of this done while there were several existing commercial Unix variants which could have been licensed instead. During its early years many scoffed at it as you have RISC-V. "It is a hobby OS. It will never be able to really compete with the likes of Solaris, HP-UX, and AIX. Heck, it won't even be able to compete with SCO and Unixware."
- sweden 9y ago
  I'm not saying that RISC-V is an hobby project, I'm just saying that hardware development is nowhere comparable to software development. You need much more support and verification while developing hardware then developing software. And while you can reuse the functional design (please note the keyword "functional"), the physical implementation needs to be redone from project to project. ARM, Intel, AMD, Apple and Qualcomm have an army of engineers with all kinds of tools that go through all the steps of hardware design and implementation which you can't do as a side project at home using just your computer.
- TheOtherHobbes 9y ago
  Linux is still a hobby OS. It's not a particularly wonderful example of software engineering. Its only real benefit is that it's free and comes with an ecosystem of other free software that kind of mostly works as long as you don't mind the occasional security horror, and can be used as-is or customised at relatively low cost. That combination of features makes it appealing in a variety of business cases - for business reasons. RISC-V can't be customised at relatively low cost. It's nominally free, but the freeness doesn't mean much in a business setting. The total cost of developing a custom core remains beyond the reach of small companies. Big companies already know there's an established ARM ecosystem with working compilers and a simple, risk-free, and relatively affordable business model. So what business problem does RISC-V solve?
  - Recurecur 9y ago

by sweden 9y ago

rwmj 9y ago

When I did a presentation on RISC-V last year I counted 6 real implementations (full custom ASICs). Now granted only one or two of those you can buy, the others are research projects, but they do exist and they did produce real silicon. This year we should see a couple of 64 bit implementations, which is when it'll get really interesting. There are of course multiple FPGA implementations (I have one about 2 feet away from me now), but they are very slow.

eggsome 9y ago
Is your presentation online?
- rwmj 9y ago
  No it was a private talk about company strategy.
sweden 9y ago
I am aware that they exist but it's not like companies are going to actively invest in devices for the end consumer purely based on RISC-V.
- sangnoir 9y ago
  From where I'm standing, it looks like you're shifting goalposts: > > RISC-V is thrown around like if it's an already working CPU but it is not (Evidence of existing CPUs provided) > I am aware that they exist but it's not like companies are going to actively invest in devices for the end consumer purely based on RISC-V.
  - sweden 9y ago
    My point is, you can't get those existing CPUs for free.
    - microcolonel 9y ago
      What kind of for free are you talking? The first commercial run RISC-V microcontroller SoC has fully-published RTL, and a company which will support you in adding it to your products (SiFive). Obviously people aren't going to give you the manufactured chips for free, but how close do you want it?

tssva 9y ago

Linux didn't instantly become something you could download from kernel.org, compile overnight and get it booting right away. It took hundreds and hundreds of developers, thousands of man hours, financial investments from a large number of companies worldwide and many many years for Linux to become what it is today. All of this done while there were several existing commercial Unix variants which could have been licensed instead. During its early years many scoffed at it as you have RISC-V. "It is a hobby OS. It will never be able to really compete with the likes of Solaris, HP-UX, and AIX. Heck, it won't even be able to compete with SCO and Unixware."

sweden 9y ago
I'm not saying that RISC-V is an hobby project, I'm just saying that hardware development is nowhere comparable to software development. You need much more support and verification while developing hardware then developing software. And while you can reuse the functional design (please note the keyword "functional"), the physical implementation needs to be redone from project to project. ARM, Intel, AMD, Apple and Qualcomm have an army of engineers with all kinds of tools that go through all the steps of hardware design and implementation which you can't do as a side project at home using just your computer.
TheOtherHobbes 9y ago
Linux is still a hobby OS. It's not a particularly wonderful example of software engineering. Its only real benefit is that it's free and comes with an ecosystem of other free software that kind of mostly works as long as you don't mind the occasional security horror, and can be used as-is or customised at relatively low cost. That combination of features makes it appealing in a variety of business cases - for business reasons. RISC-V can't be customised at relatively low cost. It's nominally free, but the freeness doesn't mean much in a business setting. The total cost of developing a custom core remains beyond the reach of small companies. Big companies already know there's an established ARM ecosystem with working compilers and a simple, risk-free, and relatively affordable business model. So what business problem does RISC-V solve?
- Recurecur 9y ago