how to create errors on floppy disks

[Buciuman Adrian]

  Can fdutils be used to make some sectors  ( but not all  ) on a floppydisk
unreadable ( i.e. give an I/O error when read from /dev/fd0 ) ?
  This can be used  to test and debug dd  and maybe other utilities ( for
data recovery etc )
  The noerror option of dd  is ( was ?? ) buggy under some conditions , but
is is imposible to reproduce/debug/test without broken disks.


   I don't know much about the low-level structure of floppy disks but I
hope
that something like :  CRC errors , sectors with unexpected lenght , sectors
with unexpected numbers , sectors spacing errors  can be created by
software.
  Using different formats for tracks may be a  quicker solution , but it
will be
nice ( and better for debuging ) to be able to make individual sectors
unreadable.


   For more details on the dd bug see this :


http://mail.gnu.org/archive/html/bug-coreutils/2003-08/threads.html#00105
http://mail.gnu.org/archive/html/bug-coreutils/2003-09/threads.html#00099
http://mail.gnu.org/archive/html/bug-coreutils/2003-10/threads.html#00069