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Text File  |  1988-11-24  |  4KB  |  77 lines
  1.           DELZ (Delete file entirely)             Steven Holzner
  2.           _______________________________________________________
  3.  
  4.           Purpose:  Allows you to delete a file absolutely by
  5.                     writing over the sector(s) it occupies.
  6.  
  7.           Format:   DELZ
  8.  
  9.                     then
  10.  
  11.                     DEL/Z [d:][path][filename[.ext]]
  12.  
  13.           Remarks:  DOS does not delete files by overwriting
  14.                     them.  Rather, the sectors used by the
  15.                     "erased" file are simply made available for
  16.                     use by subsequently written files.  Until
  17.                     they are so used, however, the original file
  18.                     can be recovered with UNDEL.COM (included in
  19.                     these utilities) or by using a comparable
  20.                     commercial product.
  21.  
  22.                     Because it overwrites the sectors used by a
  23.                     file, DELZ provides complete deletion.  A
  24.                     memory-resident utility, it attaches itself
  25.                     to DOS when loaded, normally as a command
  26.                     entered through your AUTOEXEC.BAT file.
  27.                     Thereafter, until you reboot, it provides a
  28.                     /Z (for "zero out") option for the DEL
  29.                     command.
  30.  
  31.           Example:  The disk from which you boot up your PC on
  32.                     drive A: has a copy of DELZ.COM on it, and
  33.                     the disk in drive B: has a file called
  34.                     TAXCHEAT.85 that you wish to ensure is
  35.                     completely obliterated.  From the A> prompt
  36.                     you enter DELZ to load the command into
  37.                     memory.  Then you enter
  38.  
  39.                          DEL/Z B:TAXCHEAT.85
  40.  
  41.                     Even if the TAXCHEAT.85 file is unerased, its
  42.                     original contents will now be unrecoverable.
  43.                     (The contents of that file will, in fact, be
  44.                     the machine language code of DELZ.COM
  45.                     itself.)
  46.  
  47.                     Notes:
  48.  
  49.                     1.   The Z in DEL/Z must be typed uppercase.
  50.                          The use of the global characters ? and *
  51.                          is supported.
  52.  
  53.                     2.   Because of possible conflicts with other
  54.                          memory-resident programs and utilities,
  55.                          you must check whether DELZ can be
  56.                          installed on your own system.  While
  57.                          SideKick has caused no reported
  58.                          difficulties, running XyWrite II or III,
  59.                          with or without its XYKBD.COM file, is
  60.                          impossible after DELZ is made resident.
  61.  
  62.                     3.   The use of DELZ.COM is likely to be
  63.                          reasonably infrequent, but sometimes it
  64.                          will be absolutely necessary.  If you
  65.                          find at those times that co-residency
  66.                          conflicts prevent putting it in your
  67.                          AUTOEXEC.BAT file, you may wish to keep
  68.                          a bootable disk (formatted with the /S
  69.                          option) with a copy of DELZ.COM and an
  70.                          AUTOEXEC.BAT file that loads the
  71.                          program.  If you then boot up from this
  72.                          disk you can destroy any file(s) you
  73.                          wish, remove the DELZ disk, and reboot
  74.                          your computer normally.
  75.  
  76.                     4.   Requires DOS 2.0 or higher.
  77.