hdefix(1M) MISC. REFERENCE MANUAL PAGES hdefix(1M)
NAME
hdefix - report or change bad block mapping on a hard disk
device
SYNOPSIS
/sbin/hdefix -p [ -D major minor ]
/sbin/hdefix -a [ -D major minor [ -b blockno ... ] ]
/sbin/hdefix -a [ -D major minor [ -B cyl trk sec ... ] ]
DESCRIPTION
The hdefix command is part of the bad block handling util-
ity. This command maps bad blocks to surrogate images in an
area not accessible by the user.
Before attempting to execute hdefix, the system must be
brought to the single-user state using the command init s.
Only super-user can use hdefix to print a list of blocks
currently mapped to surrogate images on the equipped hard
disk devices or to change the mapping of these blocks.
When the mapping to surrogate images is changed, block ini-
tialization is performed. If the original block can be
read, its data is written to the new surrogate image to
prevent data loss. If the original block is unreadable,
zeros are written to the new surrogate image. This will
usually result in some data loss.
If the block is associated with a file system, the file sys-
tem may be damaged as a result of the mapping change. To
handle this situation, the file system is marked dirty,
which means the fsck command must be run before the file
system can be used, and a system reboot is forced after all
other bad block processing is complete. If the block is a
data block of a file, that file will be corrupted, even
after this recovery has finished.
The following options may be used with hdefix:
-p prints a report that shows both the functional blocks
and currently mapped bad blocks. If a specific hard
disk device is specified (by giving its major and
minor device numbers), only the report for that hard
disk device is printed. If no particular hard disk
device is specified, a report is given for each
equipped disk.
-D used to specify the major device number and minor
device number of a hard disk device.
-a used to map new bad blocks. If no arguments follow
Last change: Essential Utilities 1
hdefix(1M) MISC. REFERENCE MANUAL PAGES hdefix(1M)
the -a option, all equipped hard disk devices are
processed, using the HDE Log on each hard disk device
to determine which blocks to map. If a specific hard
disk device is specified, only that disk device is
processed. If one or more block numbers are speci-
fied, those blocks are mapped, instead of using the
block numbers listed in HDE Log. This is the only
way to map an unreadable block containing the HDE
Log.
-b blockno
specifies the physical hard disk block number. Phy-
sical hard disk block numbering starts with zero,
meaning block (sector) 0 of track 0 of cylinder 0.
The blockno value ranges from block number 0 through
the maximum number of blocks on a particular hard
disk drive minus 1.
-B cyl trk sec
specifies the physical disk block number in terms of
its physical cylinder number (cyl), track number
within cylinder (trk), and sector (block) number
within track (sec). This alternate form is available
for reporting bad block data obtained without using
the normal system capabilities (e.g., off-line diag-
nostics provided by the manufacturer). This option
is not supported on SCSI disks.
FILES
/dev/hdelog
SEE ALSO
fsck(1M), init(1M), hdeadd(1M), hdelogger(1M), hdelog(7).
Bad Block Handling in the System Administrator's Guide.
RETURN CODES
The hdefix command exits with one of three values:
0 means NORMAL (or TRUE)
1 means bad command usage or execution errors
2 means BAD BLOCKS (or FALSE) (but command executed suc-
cessfully)
Last change: Essential Utilities 2