Re: question about mtd_torturetest.c

[Huang Shijie <b32955@freescale.com>]

于 2013年02月04日 14:58, Artem Bityutskiy 写道:
> 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.
>
I think the random data test is much like the simulation of the nand 
real use, such as the nand is used in
the filesystem.

thank
Huang Shijie