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zeroer(1)							     zeroer(1)

       zeroer -- wipe unallocated disk space around files


       The  zeroer  utility can	be used	to flush the empty space on a disk. In
       contrary	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 cer-
       tain  extent this works similarly to the	dd program, however zeroer dy-
       namically reduces the blockwriter's buffer size when the	disk is	 going
       to  be full. Thus, smaller fragments 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 ze-
       roer 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	centralized disk block addressing table	(e.g. inodes, file al-
       location	 table)	 and  multiple peripheral directory/ file descriptors.
       zeroer has been multi-pass tested on UFS, FAT and NTFS and the test re-
       sults show that zeroer operates quite reliably on those file systems.

       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 release.

       zeroer is released under	the GPL.

       Emanuel Haupt <> for creating a FreeBSD port.

David Schneider			      0.1			     zeroer(1)


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