Re: [Yaffs] Re: YAFFS fs images not working the way I expect

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Author: Thomas Gleixner
Date:  
To: David Wuertele
CC: YAFFS
Subject: Re: [Yaffs] Re: YAFFS fs images not working the way I expect
On Fri, 2004-10-22 at 11:35 -0700, David Wuertele wrote:
> Thomas> OOB info is part of the filesystem.
>
> If it is, the designer made a boo-boo! It isn't called "out-of-band"
> for nothing!


Yeah, I'm too stupid to understand how NAND works and you're the expert.
Design your own filesystem, if you know to do it better.

_ALL_ NAND aware filesystems, I'm aware of, use the OOB. And for the new
2K chips + Hardware ECC it is even neccecary to move parts of the fs
into the OOb layer.

> Thomas> ECC is part of error correction in the NAND layer. How should
> Thomas> this work without?
>
> 1. ECC is optional in the NAND layer


That's utter crap. It is not recommended to use NAND without ECC for a
good reason

> 2.  ECC should be a component of the NAND driver, not of the
>     filesystem.


It is part of the NAND driver, but dd and your programmer are not aware
of that. Think about that for a second

> Thomas> nandwrite from MTD/utils programs images with OOB info, ECC
> Thomas> and is bad block aware.
>
> But I need to pre-load my flash with a programmer. This is for the
> purposes of mass production, and there's no way to do it on a machine
> already running linux. How am I going to get my YAFFS partition onto
> the flash?


Oh, your programmer does not support this. There are programmers
available, which handle NAND including OOB programming.

tglx