MLC NAND: all 0xff after erase?

[Richard Genoud]

2012/7/11 Brian Norris <computersforpeace at gmail.com>:
> Hello all,
>
> I've seen some issues with MLC NAND and where I might erase a block,
> read it back, and receive a few bitflips such that the data is not
> entirely 0xff (i.e., a few bytes may be 0xfe, 0x7f, 0xf7, etc.).
If you read the same block a few ms later, is the data the same or is
it all 0xff or.. ?

> [2] Counterexample: it seems NAND_ECC_SOFT actually corrects a single
> bitflip in 0xff data. Tested with nandsim and `nandwrite -n -o`.
If I recall correctly, is because the soft ECC of an FF page is
FFFFF.. and most (maybe all) hard ECC of FF page are not.


Richard.

-- 
for me, ck means con kolivas and not calvin klein... does it mean I'm a geek ?