Command: zerofill

  ZEROFILL writes zeros on the empty disk space for the selected drive.
  It helps virtual machine, and disk compression software to compact the
  allocated space in the volume, and so on reducing its disk usage.

Syntax:

  ZEROFILL [drive:]

Options:

  - none -

Comments:

  ZEROFILL has been specially optimized to run on pure DOS enviroments,
  no matter if the are on the top of physical machines, or virtual
  machines.
  Even if FAT32 partitions are not explicitilly supported, its 64 bit
  arithmetic should make it support volumes of up to 256 GB in size,
  depending if DOS is able to properly inform about it on service 36h.
  If not, it will only be able to fill reported size at most.
  (Comment: This is theory, in reality ZEROFILL creates 4 x 512 MB big
  files and deletes them at the end of the program so that you only
  can start from the beginning). So it is actually (version 1.0.9) only
  useful for HDs smaller than 2 GB!
  HINT: In case that you want to wipe more free space search for "wipefree"
  and "Uwe Sieber". This tool has source code included, but there is NO
  documentation about the license! Use it at your own risk!

Examples:

  ZEROFILL C:
  Will fill with zeros all available space in drive C.

See also:

  - nowhere -

  Copyright © 2012-2022 Javier Gutierrez Chamorrro (Guti), help
  version 2023 W. Spiegl.

  This file is derived from the FreeDOS Spec Command HOWTO.
  See the file H2Cpying for copying conditions.