Monday 15 October 2012

Parallella

Adapteva have a kickstarter project to create a $100 highly parallel computer with an "open" architecture.

It's a pity to see they aren't getting much traction - compared to other similar projects. I guess there might be a bit of SBC fatigue setting in, and the RPI seems to be getting all the limelight, even though there's no real comparison - generic ARM board with a proprietary VPU and GPU vs a highly parallel computer which is mostly open.

This is really a lot more interesting - not only from the architectural standpoint, but because it's actually an open platform - by the guys actually designing the chips too. This alone makes it a much more interesting prospect beyond the mere performance numbers and price. e.g. I already know the programming model and instruction set from a simple pdf download, without any NDA or costs. And it's an interesting model - almost a MISC cpu core (minimal instruction set) with ARM-like mnemonics, 64 registers but the bottom 16 map 1:1 to ARM usage, and a zero-page style (6502 thing) optimised 16-bit version of each instruction for a smaller sub-set of registers/offsets. Flat address space, localised memory, DMA engines, etc. (nothing I saw about about MMU/context switching though - although both are impediments to raw performance).

As we've seen with the Allwinner A10 stuff - having a cheap SOC is one thing, but without documentation and with proprietary components it's a much much less attractive deal. It doesn't matter how fast your GPU or VPU is if you can't actually use it. Reverse engineering efforts like lima are all well and good but they are a very slow and difficult way to get anywhere, and may never succeed (and from the details they've found so far, it may be impossibly complex to programme for anyway). And they have real boards - i'm not sure what the rhombus guys are doing but they keep talking about 'scaling up to millions of boards' yet don't seem to be able to get a few 10K$ together to do the hardware design. And after 3 years of talking still don't seem to have gotten anywhere. Or the OpenPandora guys who used such a complex device as the OMAP that they wasted big money and many years before they got it to function reliably.

I'm not really one to contribute to kickstarter, but maybe in this case i'll put my money where my mouth is and put up some dough, even if it looks like they wont make the target. And that just seems to be down to some poor marketing. A video with some HD video encoding or decoding would get the kids excited (sadly this is all anyone seems to care about for these low power computers), not a picture of an ammeter or some guy gushing about how fucking excellent their shit is (true as that may be!).

Update: If you read this far, see also the follow-up post.

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