NAME    [Toc]    [Back]

     badsect - create files to contain bad sectors

SYNOPSIS    [Toc]    [Back]

     badsect bbdir sector [...]

DESCRIPTION    [Toc]    [Back]

     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 more
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 ilist
 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 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  the bad sector, and whose name is the bad sector
number.  When
     it 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.

DIAGNOSTICS    [Toc]    [Back]

     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.

SEE ALSO    [Toc]    [Back]

     bad144(8), fsck(8)

HISTORY    [Toc]    [Back]

     The badsect command appeared in 4.1BSD.

BUGS    [Toc]    [Back]

     If more than one sector which comprises a file system  fragment is bad,
     you  should  specify  only  one  of  them to badsect, as the
blocks in the bad
     sector files actually cover all the sectors in a file system
fragment.

OpenBSD      3.6                           June      5,      1993