Write those again please, encoded how

Pat LaVarre p.lavarre at IEEE.org
Tue Aug 24 10:42:03 PDT 2010


* From the T10 Reflector (t10 at t10.org), posted by:
* Pat LaVarre <p.lavarre at ieee.org>
*
Given this paradox:
a) Often SSD's include spare capacity to raise the apparent 'endurance'
of how many times the host can rewrite the sector at an LBA.
b) Such SSD's can suddenly unexpectedly lose all the gigabytes of a
whole chip die & still keep on running if the host rewrites all those
lost LBA’s by remapping those LBA's to other dies.
c) T10 SBC requires such SSD's to refuse to READ any lost sector,
instead returning a KCQ such as:
311C3h MEDIUM ERROR/ UNRECOVERED READ ERROR - VENDOR-SPECIFIC 311C3H
3110Ch MEDIUM ERROR/ UNRECOVERED READ ERROR - RECOMMEND REWRITE THE DATA
31103h MEDIUM ERROR/ MULTIPLE READ ERRORS
31100h MEDIUM ERROR/ UNRECOVERED READ ERROR
Then I ask: 
Q: What signal(s) should the drive send to suggest the host rewrite all
the LBA's of the lost die?
Merely refusing to read the lost sectors, or even all sectors, doesn't
just work. Many hosts don't then efficiently find this middle ground of
rewriting just the lost die, instead hosts waste much time by trying
each lost sector individually or by actually returning the drive for
service.
Is there no existing answer? Inventing an entirely new answer of course
wastes time in waiting for the hosts to catch up and implement it.
Thanks in advance,
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