[patch] Allow any filesystem on MTD Nand when Read Only

Pantelis Antoniou panto at intracom.gr
Thu May 6 05:45:17 EDT 2004

Thomas Gleixner wrote:

>On Thursday 06 May 2004 11:30, Srinivasu.Vaduguri at nokia.com wrote:
>>>How many times have you written the block in order for something like
>>>this to occur?
>>I haven't counted the number of times. But I remember reading some
>>information, that even on multiple reads we do get bit errors and it is a
>>symptom that the block slowly becoming bad after some time.
>Hmm. Never seen this. I have some read only paritions which are accessed in 
>stress testing and I never have seen, that a block gets bad due to reading.
>>But what I feel is, a read-only filesystem like cramfs is not that reliable
>>on NAND flash. We have to detect a bad block early.
>Yep, but you can only detect it while writing / erasing.
Actually when using ECC you *CAN* detect a single bit error.
You could use this information as a trigger to migrate the block
and then mark it bad immediately.

However it better be only one bit that flipped because if more
bits are gone you're screwed.



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