On Tue, Jan 17, 2012 at 12:43 AM, Peter Barada <peter.barada@logicpd.com> wrote:
> I need to modify YAFFS to trigger garbage collection on a block that has
> too many page reads between erases.
>
> This is due to the characterisation of the Micron NAND
> (MTMT29C4G48MAPLCJI6) I'm using where it can only have ~20K reads
> between erasures to maintain UBER below 10E-14.  The NAND itself has an
> internal 4-bit ECC engine, but I can't extract any useful information
> from the ECC due to the lack of bit error counts (i.e. the chip can only
> tell me that a read required some level of correction but not the amount
> of correction, and worse the rate of corrections indicated by the chip
> is too high to employ effective strike counting).
>
> So I need to track the page reads in a block and if they reach a limit
> then cause the block to be garbage collected (i.e. copy out all the
> useful data and erase the block).
 Just out of curiosity , is this the same as read disturb phenomena in flash?.
http://en.wikipedia.org/wiki/Flash_memory#Read_disturb

Thanks,
mugunthan