When there's only one

...there's only one choice
Everything here is my opinion. I do not speak for your employer.
February 2013
March 2013

2013-02-28 »

The guy who invented the Raspberry Pi came to visit and I got to have lunch with him.  Some surprising stuff I learned:

  • He's a technical director at a company where his project started off as discouraged and has now reached the status of being his full time job.

  • About a million units a year (their current volume) is approximately the lowest volume they would want to support.  But it is in the range they would want to support.

  • The Raspberry Pi is not just a custom board: it's a custom chip.  This guy is the chip designer.  The way it happened was he had the idea to take their existing 3D graphics coprocessor chip and squeeze a tiny ARMv6 (ARM11) core into a space on the die that was otherwise unused.  It sounds like a 20% project, basically.  The result is a rather unusual SoC that has comparatively crappy main CPU performance (700 MHz single issue), but very very good graphics/video performance.  (The full board costs $25-$35, where the $25 model has no ethernet port.)

  • He believes this tradeoff (great graphics, wimpy processor) is a good balance for a super-low-cost educational device, since students care about making cool graphics.  I think he has a point.

  • There are in fact a few other manufacturers who could make devices in the same price range as Raspberry Pi, but you'd get slightly higher CPU performance with much lower graphics performance.  Nobody else bundles a high-end graphics processor into a chip in that price range.

  • Someone on the Internet managed to reverse engineer their DSP and document how it works, writing a complete architecture manual for it.

  • Our TV box uses the same graphics chipset: "Oh, that's the exact same graphics processor then.  We only have one graphics processor design that we use across our entire line.  I designed it."

Um.  Okay then. :)

My sister got me a Raspberry Pi for Christmas (yes, we are a geeky family) and I played with it a bit, and it definitely does playback full HD video while taking super low CPU, as long as you use the coprocessor.

I'm CEO at Tailscale, where we make network problems disappear.

Why would you follow me on twitter? Use RSS.

apenwarr on gmail.com