BADSECT(8) —
NAME
badsect − create files to contain bad sectors
SYNOPSIS
/etc/badsect bbdir sector ...
DESCRIPTION
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 disk(4) and format(8R) 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.
Badsect is used on a quiet file system in the following way: 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 does not pose a problem, because the system reports relative sector numbers in its console error messages.) Next, 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 remove files containing the offending bad sectors, but do not have it remove the BAD/nnnnn files. This would leave the bad sectors only in the BAD files.
Badsect works by giving the specified sector numbers in a mknod(2) system call, creating an illegal file, the first block address of which is the block containing the bad sector(s), and the name of which is the bad-sector number. When the file is discovered by fsck, it will ask, hold bad block? A positive response will cause fsck to convert the inode to a regular file containing the bad block.
SEE ALSO
DIAGNOSTICS
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.
BUGS
If more than one sector comprising a file system fragment is bad, specify only one of them to badsect, as the blocks in the bad-sector files cover all the sectors in a file-system fragment.
PRPQs 5799-WZQ/5799-PFF: IBM/4.3 — 30 Sep 1985