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zeroer(1)							       zeroer(1)

NAME
     zeroer -- wipe unallocated disk space around files

SYNOPSIS
     zeroer

DESCRIPTION
     The  zeroer utility can be used to flush the empty space on a disk. In con-
     trary to the dd utility, zeroer doesn't wipe existing files on a partition.
     It overwrites the unallocated disk space around existing files, which means
     that deleted files cannot be restored anymore after  processing  a  certain
     partition	with  zeroer.  The  utility's principle consists in writing huge
     zero-padded memory blocks to a file. To a certain extent this  works  simi-
     larly  to	the  dd  program,  however zeroer dynamically reduces the block-
     writer's buffer size when the disk is going to be full. Thus, smaller frag-
     ments of unallocated partition space are  also  flushed,  even  though  the
     largest  unallocated  disk  areas	can be written with huge blocks and this
     means more speed.

     zeroer's principle is quite simple and there is no  guarantee  that  zeroer
     works  reliably on every file system, because zeroer doesn't know the way a
     file system works exactly. However, most file systems use a mix of  a  cen-
     tralized  disk  block addressing table (e.g. inodes, file allocation table)
     and multiple  peripheral  directory/  file  descriptors.  zeroer  has  been
     multi-pass  tested  on UFS, FAT and NTFS and the test results show that ze-
     roer operates quite reliably on those file systems.

TODO
     The current version of zeroer doesn't remove file or  directory  meta  data
     like  file  and directory names, sizes, dates, modes. Only a file's content
     is overwritten. Metadata scrambling will be implemented  in  a  future  re-
     lease.

LICENSE
     zeroer is released under the GPL.

THANKS
     Emanuel Haupt <ehaupt@FreeBSD.org> for creating a FreeBSD port.

David Schneider 		       0.1			       zeroer(1)

Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=zeroer&sektion=1&manpath=FreeBSD+Ports+15.1.quarterly>

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