[Yaffs-archive] Re: YAFS & Toshiba smart media chips

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Author: Charles Manning
Date:  
To: Stephan Linke, Yaffs List
Subject: [Yaffs-archive] Re: YAFS & Toshiba smart media chips
There are various companies using various Toshiba parts with YAFFS in
shipping products - some shipping now for over a year.

The only restrictions that you mention are:

* Number of partial page programming operations. If you rewrite a page too
many times there is a possibility you could cause varios write disturbs.
* When device performance is characterised, sometimes a limitation is that
the pages are written in a strictly sequential order.

The only time YAFFS does not writer pages sequentially or does any partial
page grogramming is when the tags are written when a page is marked discarded.

It is worth noting a few things:
* Not all discards result in pages being marked.
* Only the OOB (spare) area gets rewritten. This is less prone to write
disturb (it has a higher partial programming count).
* Write distrurbs are most likely to remain on the same page - data which is
discarded anyway.

Regards

-- Charles

On Wednesday 01 October 2003 22:31, Stephan Linke wrote:
> Hi,
>
> we are thinking about using toshiba chips on our board. They are supported
> in the linux nand driver. But there are some additional restrictions in how
> to access the pages for toshiba chips. Dealing with pages and partial
> writes is mainly a filesystem issue. So my question is if there are any
> experiences in using YAFFS on toshiba chips?
>
> Thanks, Stephan
>
>
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