On Mon, Sep 20, 2010, Arnd Bergmann wrote:
Right. Having an intelligent file system is the only way I can see for getting good speedups, by avoiding erase-cycles inside the SD card, which commonly happen when you write to sectors at random addresses.
There has been a lot of research in optimizing for regular NAND flash, at least some of which should apply to SD cards as well, although their naive wear-levelling algorithms might easily get in the way.
This sounds like a relatively large task; do you think that's something we could build on existing infrastructure like some ubi bits or some btrfs bits?
I'm worried that we don't really know what the SD wear-levelling is doing, and it might change over time; I'm not sure whether we can introspect the way the controllers do it, or whether we'd have some fragile heuristics to decide that this or that SD card manufacturer uses this kind of algorithm :-/
Also, do we know enough about the underlying hardware to basically override what the manufacturer is trying to do?