BADSECT(8) | System Manager's Manual | BADSECT(8) |
badsect
—
badsect |
bbdir sector ... |
badsect
makes a file to contain a bad sector. Normally,
bad sectors are made inaccessible by the standard formatter, which provides a
forwarding table for bad sectors to the driver; see
bad144(8) for details. If a
driver supports the bad blocking standard it is much preferable to use that
method to isolate bad blocks, since the bad block forwarding makes the pack
appear perfect, and such packs can then be copied with
dd(1). The technique used by this
program is also less general than bad block forwarding, as
badsect
can't make amends for bad blocks in the i-list
of file systems or in swap areas.
On some disks, adding a sector which is suddenly bad to the bad
sector table currently requires the running of the standard DEC formatter.
Thus to deal with a newly bad block or on disks where the drivers do not
support the bad-blocking standard badsect
may be
used to good effect.
badsect
is used on a quiet file system in
the following way: First mount the file system, and change to its root
directory. Make a directory BAD
there. Run
badsect
giving as argument the
BAD directory followed by all the bad sectors you wish
to add. The sector numbers must be relative to the beginning of the file
system, but this is not hard as the system reports relative sector numbers
in its console error messages. Then change back to the root directory,
unmount the file system and run
fsck(8) on the file system. The
bad sectors should show up in two files or in the bad sector files and the
free list. Have fsck(8) remove
files containing the offending bad sectors, but do not
have it remove the BAD/nnnnn
files. This will leave the bad sectors in only the
BAD
files.
badsect
works by giving the specified
sector numbers in a mknod(2)
system call, creating an illegal file whose first block address is the block
containing bad sector and whose name is the bad sector number. When it is
discovered by fsck(8) it will
ask “HOLD BAD BLOCK ?
” A positive
response will cause fsck(8) to
convert the inode to a regular file containing the bad block.
badsect
refuses to attach a block that resides in a
critical area or is out of range of the file system. A warning is issued if
the block is already in use.
badsect
command appeared in
4.1BSD.
badsect
, as the blocks in
the bad sector files actually cover all the sectors in a file system fragment.
June 5, 1993 | NetBSD 9.4 |