zeroer(1)zeroer(1)NAMEzeroer-- wipe unallocated disk space around files
SYNOPSISzeroerDESCRIPTION
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
dynamically 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
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 centralized 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 zeroer 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 release.
LICENSEzeroer is released under the GPL.
THANKS
Emanuel Haupt <ehaupt@FreeBSD.org> for creating a FreeBSD port.
David Schneider 0.1 zeroer(1)
