BADSECT(8)              GENIX Programmer's Manual              BADSECT(8)



      NAME
           badsect - create files to contain bad sectors

      SYNOPSIS
           /etc/badsect 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.  If  a  driver  sup-
           ports  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(8).  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:  First
           mount  the  file  system,  and change to its root directory.  Make a
           directory BAD there and change into it.  Run badsect giving as argu-
           ment  all  the  bad  sectors  you  wish to add.  (The sector numbers
           should be relative to the beginning of the file system, but this  is
           not  hard to do 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  a regular file whose first block address is
           the block containing bad sector and whose name  is  the  bad  sector
           number.   The  file  has 0 length, but the check programs will still
           consider it to contain the block containing the  sector.   This  has
           the  pleasant  effect  that the sector is completely inaccessible to
           the containing file system since it is not  available  by  accessing
           the file.

      SEE ALSO
           bad144(8), fsck (8)

      BUGS
           If both sectors which comprise a (1024 byte) disk block are bad, you
           should specify only one of them to badsect, as the blocks in the bad
           sector files actually cover both (bad) disk sectors.









      Printed 11/16/83                                                        1