Disk geometry checking and repair tool
# $Header: /CVSROOT/diskus/DESCRIPTION,v 1.3 2009-02-16 05:06:50 tino Exp $
#
# $Log: DESCRIPTION,v $
# Revision 1.3  2009-02-16 05:06:50  tino
# Documentation improved very little
#
# Revision 1.2  2009-01-03 15:48:57  tino
# Output now uses scaling, more reliable read mode
#
# Revision 1.1  2007-09-18 03:05:46  tino
# First version

DISKUS is a high level harddrive diagnostic and limited repair tool.

It checks the disk geometry by writing sectors with a numbered ID to
the harddrive.  (THIS ERASES ALL DATA ON THE DEVICE!)  Later you can
verify if the sector-IDs on the disk are still correct, thereby
detecting any case where some data was written to the wrong sector (or
was not written at all).  One example use is to check if some elder
SD-card-readers are able to access the second GB - some just overwrite
the first GB two times, and diskus will detect such a bug.

Now you can "freshen" the data on your harddrive, too, this will read
and re-write the sectors.  With modern drives this will re-map all
defective sectors.  (I needed this new function to successfully revive
one of my drives while keeping all data intact.)  Note that this
option was not thoroughly tested (it was not yet tested with drives
with read errors), so if you use this new option, be sure to have a
backup (or some filesystem like ZFS which is able to fix any left over
data error).

You can also NUL the drive (like dd if=/dev/zero of=/dev/hdwhatever),
just checkread it or do a hexdump.  Diskus uses O_DIRECT/O_SYNC to
lessen memory cache impact and has a little progress meter.

Please note that diskus is no tool to erase your harddrive according
to DOD algorithms or write certain bit check patterns or data onto it
like dd.