[Yaffs] Re: bit error rates

[Peter Barada]

On Fri, 2006-02-10 at 15:39 +0000, Jon Masters wrote:
> On 2/9/06, Peter Barada <peterb at logicpd.com> wrote:
> 
> >  I use a YAFFS1 NOR-based system, and in the writes, we lay
> > down the data chunk, and then the tag.  In the unlikely event that a
> > power-cycle occurs while writing the data, the tag is still empty, but
> > some of the data chunk is not erased, and then next time a write occurs
> > into that chunk, YAFFS sees that the write fails since the previous data
> > was written(and retires the whole block), even though the tag indicated
> > the chunk is empty.
> 
> That does seem to be preferable over writing the tag twice.

Why?

This is done when YAFFS deletes a chunk by rewriting the tag to change
the pageStatus to zero.  I'm only making a single-bit 1->0 transition in
the second tag write.

> Jon.