Tuesday, 3 August 2010

Debian Linux on cheap MIPS mini netbook

Computing-wise, I've taken a break from the JamVM/OpenJDK port for a couple of days while I play with my latest toy : a cheap mini-netbook based on a Chinese MIPS clone. It's branded CnMbook, but it's available (or was) under dozens of names.

Yes, it's been available for a while. I first investigated it over a year ago as I wanted a MIPS machine on which I could do the port of the code-copying JIT (I did the MIPS port of JamVM back in 2007, and I've not touched it since). But it was 170 pounds, which was too much for the tiny spec, and I got an EeePC instead.

However, I still don't like Intel, even though it finally became my main architecture in 2008 (albeit AMD). And I like it even less as a mobile processor, as it's the last area where it doesn't dominate.

So what lead to this sudden surge of interest? I've been waiting for years for the fabled ARM-based netbooks, and a couple of weeks ago I saw a cheap WinCE mini-netbook in a local discount shop which I was passing. My brother (the author of SquashFS) thought it shouldn't be too difficult to get Linux working on it. This lead to a weekend long investigation, which showed up some startling results.

The mini-netbooks appear to be based on one of two ARM9-based SoCs (so these still aren't the low-cost Cortex A8 ones I've been waiting for). Either the Anyka AK7802 or Via's WonderMedia VT8505 SoC. The amazing thing? There's no publicly available Linux kernel (with source) for any of them. There is a binary-only Android kernel for the VT8505 but no public source. For the AK7802 there's nothing, and as Anyka have not made any SoC documentation publicly available it's likely that there never will be.

In contrast, Ingenic, the maker of the MIPS clone in the CnMbook have made available the full source to their modified kernel, u-boot bootloader, rootfs and applications. It came with CELinux, and an ancient 2.4.20 kernel. But it didn't take my brother long to get a modern-ish 2.6.24 kernel running on it (he's working on 2.6.31), and with Debian MIPS Linux it makes a nice little portable development system. Compiling is rather slow, but vim runs well on console, which is all you need!

The cost? 65 quid off ebay for an ex-display model as you can't buy them anymore, the ARM9 WinCE machines having completely replaced them.

I'll next post my experience of running JamVM/OpenJDK on it :)