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Building a RISC-V PC

345 points| spystath | 7 years ago |abopen.com | reply

99 comments

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[+] avisaven|7 years ago|reply
If you want to play with RISC-V hardware right now, I highly recommend taking a look at the Sipeed MAIX [1]. It has a bunch of neat features along with a dedicated RISC-V processor, for a considerably lower price (~$35 if my memory is correct). I've received a M1w, which is working quite well. The campaign has ended but it seems you can get the hardware on external retailers, however I cannot vouch for these [2]. They also have a Telegram chat where the developers of the product talk quite a bit, and if you ever have any questions they're quite responsive and helpful.

[1] https://www.indiegogo.com/projects/sipeed-maix-the-world-fir... [2] https://www.seeedstudio.com/Sipeed-MAIX-I-module-WiFi-versio...

[+] jokr004|7 years ago|reply
I just got my hands on one of these through the indiegogo campaign. Really cool! I just got micropython running, going to sit down with it this weekend
[+] shadeslayer|7 years ago|reply
I saw one of these at FOSDEM recently and it could already run a full Linux graphics stack all the way to KDE Plasma. So cool :D
[+] microcolonel|7 years ago|reply
I want to get back to porting Chromium, because when AMD tries the second time around [0] (edit: maybe third time around, as wmf below points out) to do a pin-compatible RISC (maybe this time it's one of the Zen 4 platforms or whatever), I want to pop the phattest GPU in that thing and enjoy.

[0]: https://www.extremetech.com/computing/181867-amds-project-sk...

[+] dfox|7 years ago|reply
Actually it would be fourth time around, as the K7 Athlons/Thunderbirds were electrically compatible with Alpha 21264, although OK, it was not pin nor mechanically compatible as Alpha CPUs need additional directly attached serial (EE)PROM with boot PALcode/microcode/firmware/initial contents of L2 cache. On the other hand on typical lowend Alpha systems this PROM contained complete enought i386 emulator that it could run PC-style BIOS as part of hardware initialization (ie. work with ISA/PCI cards with x86 code in PROMs), somewhat ugly and scary is the fact that large part of the firmware variant needed for booting Windows NT was actually i386 code running in said emulator. (And then there is Linux, which in the somewhat Tour de force way does not care about the underlying PALcode API)

--- ) Alpha is to a large extent the ultimate RISC architecture that on the user side does not have any implicit sideefects of instructions and syscalls and interrupts work by simply exchanging two register sets. The idea is that there is PALcode which is the only privileged code running on the CPU, which then keeps track of whether whatever is currently running in userspace is user or kernel code and passes messages between these, to some extent it is microkernel as part of the CPU, which you additionally can as an OS modify (in reality you could not, because the PALcode is amalgamation of both the OS semantics, quirks of the actual CPU implementation and the actual motherboard in given system)

[+] spitfire|7 years ago|reply
Back in the 1990's when the AMD Athlon first came out Slot 1 was supposed to share the bus with the DEC Alpha. The idea was you replace the bios and you could use the same motherboard for both DEC Alpha or AMD Athlon.

Of course, that never happened. But people keep wishing.

[+] wmf|7 years ago|reply
Before that there was going to be an IBM Power chip to fit in an Opteron socket.
[+] yjftsjthsd-h|7 years ago|reply
That's beautiful. Did it fall through?
[+] VoxPelli|7 years ago|reply
One of the amazing possibilities with RISC-V will be how it democratizes chip designing and by that opens up the ability to innovate in an area of computing that so far has been reserved to a selected few.

RISC-V isn't really about price or performance – it's about innovation, agility, exploration and new frontiers.

[+] snazz|7 years ago|reply
I had heard of the SiFive/HiFive Unleashed, but not of the expansion board. I’m surprised that it “just worked” and I really like the case!
[+] bcaa7f3a8bbc|7 years ago|reply
The article didn't mention that the development board costs 1000 USD and the expansion board costs another 2000 USD, and it's only a barebone system, a full system comparable to a high-performance PC would require another 500 USD. At this price level (~3000+USD), one can almost purchase an OpenPOWER-based workstation (as we already have seen, the crowdfund campaign for Talos Secure Workstation failed due to its price, https://www.phoronix.com/scan.php?page=article&item=talos-wo...). So no, I still don't think RISC-V is as usable as a PC for an average user at its current shape as a prototype for developers.
[+] rwmj|7 years ago|reply
It "just worked" thanks to huge amounts of work by folk from WDC, SiFive, Microsemi, Fedora, and Debian.
[+] tachyonbeam|7 years ago|reply
How does the quad-core 64-bit RISC-V processor used perform? Genuinely curious to know how to compares to a modern ARM cellphone chip, for example.
[+] rwmj|7 years ago|reply
I have two of these boards which are part of the Fedora build system (see http://fedora.riscv.rocks/koji/). The performance is fine for light development, but they're not blazingly fast -- and we don't expect that, it's the first development board available only in small quantities. The chip itself is an in-order design, something like the A53.
[+] mrweasel|7 years ago|reply
Is there some reason for the "funny" form factor of the HiFive boards? It seems like a mini-ITX or ATX form factor would be more appealing to many.
[+] justinclift|7 years ago|reply
Probably because it's a development board in spirit, not really intended for any kind of PC usage.

Hopefully some future product(s) with more PC compatible form factors come out in the next few years. :)

[+] justinclift|7 years ago|reply
Using some right angle PCIe connectors for the graphics and USB expansion cards, they'd probably be able to shrink the height of that case significantly.
[+] gmueckl|7 years ago|reply
Now if the HiFive could be scaled uo to match the performance of a current x86 CPU, this might become a serious contender for a decent set of applications.
[+] yjftsjthsd-h|7 years ago|reply
It doesn't need to hit the same perf as high-end x86 to be useful for a lot of uses; observe the sheer number of IoT projects run on Raspberry Pi and the like. Now, of course, I think we all would like to see high-end riscv be a thing so we can ditch x86 in that market segment too.
[+] VoxPelli|7 years ago|reply
If nothing else, it can at least be part of your hard drive: https://www.anandtech.com/show/13678/western-digital-reveals...

The main CPU is just one of many chips in a computer nowadays – even some cables have ARM-chips built into them to convert signals. RISC-V can probably be an even better fit there as its open design makes it a lot easier to customize it so that its tailored for such specific tasks.

[+] robdachshund|7 years ago|reply
I think it's coming sooner rather than later. Obviously arm has the upper hand here but windows is still exclusive to qualcomm.

The interesting bit here is that from what I've heard, RISC V could be twice as efficient as ARM. Couple that with the open source model and we could see some real shifts in computing very soon.

[+] Timothycquinn|7 years ago|reply
Anybody have an idea what the BOM cost is of this build?
[+] baobrien|7 years ago|reply
The Risc-V board was about $1000 the last time I checked, and the microsemi expansion thing was $2000. The SiFive board is for a small run development chip and the microsemi has a big honkin' FPGA, so the prices aren't unreasonable for that.
[+] agumonkey|7 years ago|reply
microsemi logo looks sooo much like a 90s MSDN/Office one I took 10 seconds to be sure if it was MICROSOFT or not
[+] dfed-mpls|7 years ago|reply
"RISC architecture is gonna change everything."
[+] TomVDB|7 years ago|reply
Out in the real world, I know of cases where proprietary CPU or DSP IP was rejected in favor of RISC-V alternatives.

RISC-V may not change everything, but I do believe that it will change on thing in a major way: the financials of CPU IP such as Tensilica, Cortex-M0, ARC etc.

There is very little friction in replacing embedded controllers that are not customer facing. And that's a market were $0.01 in licensing fees can be a big deal.

Edit: in the maker world, the so-called Blue Pill is incredibly popular. It has an STM32F103 SOC with a 72MHz Cortex M3 and tons of digital and analog interfaces. On AliExpress, these boards go for $1.60 a piece!

https://wiki.stm32duino.com/index.php?title=Blue_Pill

[+] mindcrime|7 years ago|reply
FYI man, alright. You could sit at home, and do like absolutely nothing, and your name goes through like 17 computers a day. 1984? Yeah right, man. That's a typo. Orwell is here now. He's livin' large. We have no names, man. No names. We are nameless!
[+] nsb1|7 years ago|reply
"Yeah, RISC is good."
[+] wmf|7 years ago|reply
Fifth time's the charm.
[+] rnvhhynr|7 years ago|reply
Why a video instead of text + photos?
[+] chrisseaton|7 years ago|reply
I don't know what you mean - the article looks to me like text and photos, and then a short video as well.
[+] silur|7 years ago|reply
I'm a big fan of RISC-V but HiFive completely ruined the whole point. I was excited for a _proper_ open ISA because it would open up super low cost hardware development. But looking at the $35 raspberry pi with a license-bound ARM ISA and a supposedly open source board for $1000 it looks like HiFive is playing by intel's or ARM's rules. No chance for risc-v adoption with this ridiculous overpricing
[+] wolfgke|7 years ago|reply
> But looking at the $35 raspberry pi with a license-bound ARM ISA and a supposedly open source board for $1000 it looks like HiFive is playing by intel's or ARM's rules. No chance for risc-v adoption with this ridiculous overpricing

This is the first revision of a developer board. It is intended for die-hard open source fanatics with money and (this is the real audience) professional developers who want to port operating systems (and perhaps their software) to RISC-V. Such developer boards are always expensive. Cheaper board will become available as soon as this audience is saturated. Then a next (cheaper) revision will be put to market that targets user mode software developers. This revision will still be expensive, but already cheaper. The following revision will target adventurous tinkerers. etc.

And so it trickles down and slowly the price decreases over time. But if you want to take a bet: it will nevertheless stay much more expensive than a Raspberry Pi for a long time.

[+] imtringued|7 years ago|reply
The Raspberry Pi is based on an obsolete old graphics chip called Video Core IV with some ARM cores added as an afterthought. Of course it's cheap, it had a 10 year headstart and benefited from the economies of scale of the original product. And as you can figure out almost every SBC is based on old TV boxes (sometimes laptops like RK3399) because that way you can just slap the old SoC on a PCB and sell it without making a completely new SoC. The vast majority of phone SoC's simply do not have the interfaces (often just a single port for USB, network, and eMMC storage, display, perfectly designed for the phone in question) required by SBCs.

In short the production run is very small and that's why it's so expensive. ARM SBCs with custom SoCs cost around the same. Just take a look at linaro's ARM desktop [0] It's $1200 and doesn't even come with 8GB of RAM.

[0] https://www.96boards.org/product/developerbox/

[+] tverbeure|7 years ago|reply
RISC-V has already been adopted by many companies as low and not-so-low performance embedded microcontrollers. It's just that you don't see it. And it's really perfect for that.

I think that's pretty exciting.

As for super low cost hardware development: you can add a RISC-V CPU to FPGAs with as little as, say, 1500 LUTs, which can be purchased for less than $10.

I don't understand you mean by "proper open ISA".

[+] detaro|7 years ago|reply
Do $5000 ARM servers kill the point of the Raspberry Pi?

The point of an open ISA is not "every product made with it is super cheap" (licensing is a tiny aspect of it), and expecting a newly developed, small-volume product to compete with something made by an established player at multiple orders of magnitude larger scale is totally unrealistic.

There's smaller, cheaper RISC-V products out there if you want something risc-v to play with. Serious adoption is going to happen at different places and not bound to "what does an HiFive dev kit cost", that's a rounding error in many places.

[+] wmf|7 years ago|reply
Many people are in for a rude awakening when they realize that a free ISA saves them like 1% or less of system cost. It certainly can't overcome the ~10x cost difference between a low-volume prototype board and a mass-produced board.

RPi also kind of ruined the hardware world because AFAIK the SoC was being dumped below cost; I'm not sure if that's still true.

[+] pjc50|7 years ago|reply
> super low cost hardware development.

There are lots of things that cost money in hardware design, and ISA licensing is a very small part of them.

Edit: I wonder if I should do a rather confrontational blog post telling people why Open hardware is never going to be the free lunch that open source software is..

[+] newnewpdro|7 years ago|reply
Give it some time to mature into a large-scale production. Comparing the cost of what's damn near a developer prototype board to Raspberry Pis manufactured in the millions is like comparing the cost of a yacht to a honda civic.
[+] mkgolden|7 years ago|reply
Check out the LoFive RISC-V development board
[+] makapuf|7 years ago|reply
Since HiFive is to my knowledge the only ones producing such kind of silicon chips with this instruction set, it is infinitely cheaper than other options, reducing the average price by NaN. I fail to see how more supply for an open architecture raises prices.