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  1.  
  2.  
  3.           DELZ (Delete file entirely)             Steven Holzner
  4.           Command                      PC Magazine, Vol 4, No 21
  5.                Copyright 1985 Ziff-Davis Publishing Company
  6.           _______________________________________________________
  7.  
  8.           Purpose:  Allows you to delete a file absolutely by
  9.                     writing over the sector(s) it occupies.
  10.  
  11.           Format:   DELZ
  12.  
  13.                     then
  14.  
  15.                     DEL/Z [d:][path][filename[.ext]]
  16.  
  17.           Remarks:  DOS does not delete files by overwriting
  18.                     them.  Rather, the sectors used by the
  19.                     "erased" file are simply made available for
  20.                     use by subsequently written files.  Until
  21.                     they are so used, however, the original file
  22.                     can be recovered with UNDEL.COM (included in
  23.                     these utilities) or by using a comparable
  24.                     commercial product.
  25.  
  26.                     Because it overwrites the sectors used by a
  27.                     file, DELZ provides complete deletion.  A
  28.                     memory-resident utility, it attaches itself
  29.                     to DOS when loaded, normally as a command
  30.                     entered through your AUTOEXEC.BAT file.
  31.                     Thereafter, until you reboot, it provides a
  32.                     /Z (for "zero out") option for the DEL
  33.                     command.
  34.  
  35.           Example:  The disk from which you boot up your PC on
  36.                     drive A: has a copy of DELZ.COM on it, and
  37.                     the disk in drive B: has a file called
  38.                     TAXCHEAT.85 that you wish to ensure is
  39.                     completely obliterated.  From the A> prompt
  40.                     you enter DELZ to load the command into
  41.                     memory.  Then you enter
  42.  
  43.                          DEL/Z B:TAXCHEAT.85
  44.  
  45.                     Even if the TAXCHEAT.85 file is unerased, its
  46.                     original contents will now be unrecoverable.
  47.                     (The contents of that file will, in fact, be
  48.                     the machine language code of DELZ.COM
  49.                     itself.)
  50.  
  51.                     Notes:
  52.  
  53.                     1.   The Z in DEL/Z must be typed uppercase.
  54.                          The use of the global characters ? and *
  55.                          is supported.
  56.  
  57.                     2.   Because of possible conflicts with other
  58.                          memory-resident programs and utilities,
  59.                          you must check whether DELZ can be
  60.                          installed on your own system.  While
  61.                          SideKick has caused no reported
  62.                          difficulties, running XyWrite II or III,
  63.                          with or without its XYKBD.COM file, is
  64.                          impossible after DELZ is made resident.
  65.  
  66.                     3.   The use of DELZ.COM is likely to be
  67.                          reasonably infrequent, but sometimes it
  68.                          will be absolutely necessary.  If you
  69.                          find at those times that co-residency
  70.                          conflicts prevent putting it in your
  71.                          AUTOEXEC.BAT file, you may wish to keep
  72.                          a bootable disk (formatted with the /S
  73.                          option) with a copy of DELZ.COM and an
  74.                          AUTOEXEC.BAT file that loads the
  75.                          program.  If you then boot up from this
  76.                          disk you can destroy any file(s) you
  77.                          wish, remove the DELZ disk, and reboot
  78.                          your computer normally.
  79.  
  80.                     4.   Requires DOS 2.0 or higher.
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