On 09/02/18 21:22, Marc MERLIN wrote:
Interesting. I figured once a sector went pending once, it would not actually be re-used and
be remapped on the next write. Seems like it didn't happen here.
Because there's all sorts of reasons a sector can go pending.
My favourite example is to compare it to DRAM. DRAM needs refreshing
every couple of seconds, otherwise it loses its contents and cannot be
read, but it's perfectly okay to rewrite and re-use it.
Likewise, the magnetism in a drive can decay such that the data is
unreadable, but there's nothing actually wrong with the drive. (If the
data next door is repeatedly rewritten, the rewrite can "leak" and trash
nearby data ...) The decay time for that should be years.
The problem of course is when the problem has a decay time measured in
minutes or hours. The rewrite succeeds, so the sector doesn't get
remapped, but when you next read it it has died :-(
Cheers,
Wol
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