-- wipe unallocated disk space around files
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 certain extent this
works similarly to the dd program, however zeroer
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
's principle is quite simple and there is no guarantee that
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.
has been multi-pass tested on UFS, FAT and NTFS and the test
results 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.
is released under the GPL.
Emanuel Haupt <ehaupt@FreeBSD.org> for creating a FreeBSD port.