karl@cygnet.UUCP (Karl Danz) (06/09/84)
Subject: Problem with adding entries to bad sector list.
Index: /sys/vax/dkbad.c 4.2BSD Fix
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Description:
For some disks, the bad144(8) utility can be used to add entries
to the bad sector list after a disk has been in use for a while.
These new entries must be placed at the end of the list since the
remapping to new sectors is based only on relative position of
entries in the list. The remapping routine, isbad(), assumes an
ordered list (apparently in the interest of efficiency) and can
exit before noticing new entries.
Repeat-By:
Add a new entry to the bad sector list with bad144, specifying
the "-f" flag (only allowed on RP06's, eagles, and capricorns).
The new sector number must be smaller than the largest number
currently in the list for the bug to manifest itself. Somehow
force I/O to the bad sector (e.g. copy a big file several times).
A hard BSE (bad sector error) will be reported and no remapping
will occur.
Fix:
One line change to /sys/vax/dkbad.c follows. Note that this is
really not going to slow things down very much as isbad() will
still bail out at the end of the active list (entries after that
are set to -1). Besides, BSE's typically occur infrequently.
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RCS file: dkbad.c,v
retrieving revision 1.1
diff -r1.1 dkbad.c
25c25
< if (blk < bblk || bblk < 0)
---
> if (bblk < 0)
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Karl Danz
Cygnet Systems