Re: question about mtd_torturetest.c

[Artem Bityutskiy <dedekind1@gmail.com>]

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On Mon, 2013-02-04 at 05:19 +0000, Gupta, Pekon wrote:
> > On Wed, 2013-01-23 at 15:25 +0800, Huang Shijie wrote:
> > > Hi all:
> > >
> > >     The mtd_torturetest.c uses the 55/AA patterns to torture the nand
> > block.
> > > Are the 55/AA patterns more tougher then the random data?
> > 
> > Probably not, please, improve the test.
> > 
> 
> (0x55/0xAA/0x55) pattern ensures that _all_ bits in the byte transition from 0-> 1, and 1->0,
> Whereas, a random pattern may miss a bit-cell or miss transition sequence, of an bad bit-cell.
> Exercising each bit both ways is important so as to differentiate a bad bit-cell (permanent error) from read-disturb errors (temporary error).
> 
> For read-disturb: http://download.micron.com/pdf/presentations/events/flash_mem_summit_jcooke_inconvenient_truths_nand.pdf

Sure, I did not mean remove those, I meant that random data test can
also be added and that would be an improvement.

-- 
Best Regards,
Artem Bityutskiy

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