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badsect(8)							   badsect(8)


  badsect - Creates files to contain bad sectors


  /usr/sbin/badsect bbdir sector...


  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:

   1.  Mount the file system and change	to its root directory.

   2.  Make a directory	BAD there.

   3.  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 mes-

   4.  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.


  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	sec-
  tor files cover all the sectors in a file system fragment.


  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.


  Commands: fsck(8)