[Yaffs] Re: power fail testing

[Sergei Sharonov]

> Two things that can be done to improve the situation at the low level:
> 1) Ensure that the whole page write is being done as a single=20
> write at the mtd level (ie. writing the data and oob as separate=20
> operations is not good).

Hmm... I would think separate writes would be a good idea - then we
have a guarantee that data write has completed. That is if crc on tags=20
is good then no power failure has occurred during data write. On the
other
hand if we do a write in one gulp then valid crc on tags does not prove
that data is ok. So:
1. In case of separate writes:
- no need to check ecc on data at scan time
- must check erase status before write (we do that anyway) since data
may=20
be written and oob not. Come to think of it we have to do it only on
first allocation.
2. In case of a single write:
- good crc on tags does not guarantee good ecc on data since it may be=20
a partial write.

So what is the problem with two separate writes (data and oob)?

Sergei
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