badsect(8)						      System Manager's Manual							badsect(8)

NAME

       badsect - Creates files to contain bad sectors

SYNOPSIS

       /usr/sbin/badsect bbdir sector...

DESCRIPTION

       The  badsect  command  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. If a driver supports the bad blocking standard, it is  preferable  to  use  that
       method  to isolate bad blocks because the bad block forwarding makes the disk appear perfect, and such disks can then be copied with dd(1).
       The technique used by badsect is also less general than bad block forwarding, as badsect cannot make amends for bad blocks in the i-list of
       file systems or in swap areas.

       On  some  disks,  adding  a  sector  that is suddenly bad to the bad sector table currently requires the running of the standard formatter.
       Thus, to deal with a newly bad block or on disks where the drivers do not support the bad-blocking standard, badsect can be  used  to  good
       effect.

       Use the badsect command on a quiet file system in the following way: Mount the file system and change to its root directory.  Make a direc-
       tory 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, as reported in console error messages.)	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 operation will
       leave the bad sectors in only the BAD files.

       The badsect command 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 fsck discovers the file, it will ask "HOLD BAD
       BLOCK?"	An affirmative response will cause fsck to convert the inode to a regular file containing the bad block.

RESTRICTIONS

       If more than one of the sectors comprised by a file system fragment are bad, you should specify only one to badsect, as the blocks  in  the
       bad sector files cover all the sectors in a file system fragment.

ERRORS

       The  badsect  command 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.

SEE ALSO

       Commands: fsck(8)

																	badsect(8)