nand flash (was Re: flashing linksys with netbsd)

On Fri, Oct 05, 2007 at 12:09:10AM +0900, Toru Nishimura wrote:
> David Young [email protected]  said;
> 
> >Let me suggest a few embedded projects that I believe are less risky and
> >more widely applicable.
> >
> >       * develop a driver for the NAND Flash storage on the RouterBOARD
> >        1xx series, www.RouterBOARD.com.  Demo writing a bootable
> >         NetBSD image to the Flash.  Demo running NetBSD from the flash
> >         (read-only).
> >
> >         (RouterBOARD is an open-architecture board with MiniPCI slots
> >         for wireless cards, et cetera.  The cheapest boards in the
> >         1xx series have no CompactFlash slot.)
> 
> I've ported NetBSD to Mesa Electronics 4C81 PC104plus SBC.  The storage
> is 32MB/64MB bare NAND which holds BSDFFS.  Bad blocks are forwarded
> by a preconfigured badblock list.  No MTD included.  Bootloader knows and
> handles /netbsd.  The NAND block device driver allows writes.  It'd be 
> likely
> to get highly criticized but the decision was made weighing "the rootfs is
> seldom written beyond configuration mods by administrators."  Software ECC
> is always calc'ed and verified, block write is counted and recorded inside
> NAND spare fields.

How do you handle the bad blocks that develop as the device "wears" ?

Dave

-- 
David Young             OJC Technologies
[email protected]      Urbana, IL * (217) 278-3933 ext 24