Re: NAND flash misery
- From: John Devereux <jdREMOVE@xxxxxxxxxxxxxxxxxx>
- Date: Fri, 27 Jun 2008 18:37:30 +0100
Vladimir Vassilevsky <antispam_bogus@xxxxxxxxxxx> writes:
cs_posting@xxxxxxxxxxx wrote:
Guess how many bad blocks are typical for NAND flash of several GB
capacity? As many as 2 percent! There could be the whole areas of
hundreds of megabytes of the contiguous bad cells, as well as the random
scatter.
I thought the IDE interface was supposed to hide that from the host by
mapping in spares?
It clearly does that, but only to a limited amount. Also, when a file
gets broken because of the bad block, it is too late to replace it.
Just because the device is manufactured with bad blocks, does not
*automatically* mean that more will follow. (At least you have not
demonstrated that).
It's not like a load of bad blocks appearing on a magnetic drive,
where you know the whole drive is probably on the way out.
Isn't it also supposed to do wear leveling behind your back?
There is a whole lot of things that the internal controller could
probably do; but we can only guess about what it actually does.
It's the same for conventional disks isn't it?
--
John Devereux
.
- References:
- NAND flash misery
- From: Vladimir Vassilevsky
- Re: NAND flash misery
- From: cs_posting
- Re: NAND flash misery
- From: Vladimir Vassilevsky
- NAND flash misery
- Prev by Date: Re: NAND flash misery
- Next by Date: Re: 24 bit math on 8 bit micros
- Previous by thread: Re: NAND flash misery
- Next by thread: Re: NAND flash misery
- Index(es):
Relevant Pages
|
