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nuke_help
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1998-06-14
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nuke (1.01d) - 'definitive' files eraser
nuke is a small disc utility that allows you to erase files from the disc
surface, filling their sectors with '0's or with a user-definable string.
nuke can also perform the same operation on all the free space of the disc so
that you can delete all the files you want in the usual way (eg. from the
filer) and then nuke the space they previously used on the disc.
Usage
-----
nuke [-options] [-s string] [-p pattern] [-n number] pathname
-f erase all the free space on disc
-r recurse in directories
-y don't ask for confirmation before nuking
-s fill nuked sectors with "string" instead of '0'
-p fill nuked sectors with numeric "pattern" (32 bit value)
-R fill nuked sectors with random data
-v verbose mode
-n overwrite the sectors "number" times
-m military mode... for very paranoid people!
If "pathname" is a directory name the -r options must be specified (unless
you use -f, in which case the directory name will be ignored and the free
space will be nuked).
The -p option accepts numeric values (either decimal or hexadecimal preceded
by '&') which are always converted to 32 bit values. Hence, if you want to
fill the sectors with &11 you have to specify &11111111 otherwise the sectors
will be filled with &11000000.
The -m option can be used together with -n and one between -R, -s and -p and
it performs the following wiping operations:
* 'n' overwrites with random data (where 'n' is as specified by -n,
default to a single random overwrite)
* one overwrite with &AA55AA55 fill pattern
* one overwrite with &55AA55AA fill pattern
* one overwrite with &00000000 fill pattern
* one overwrite with user-specified data (if the -R, -s or -p option is used,
otherwise default to another &00000000 fill pattern)
Why can nuke be useful?
-----------------------
I wrote this simple program since I am going to sell my old A410 and I don't
like the idea that other people may be able to read some of my private data.
In fact 'undeleting' a file is almost impossible on RISC OS, but someone can
use a disc editor and (at least) read the text files (mails, sources, etc.)
and eventually some file that is quite easy to identify (GIF, Draw, etc.).
I think that nuke can be useful in a school or in any other environment where
someone has to use a 'public' computer and doesn't want to leave some private
(or compromising!) data on it.
I implemented the option to overwrite more than once the sectors because I
have been told that it could be possible to read part of the data if the
sector has been overwritten only once (using some particular equipment)...
I think this is a bit paranoid, though!
For paranoid people, the possibility to fill the sectors with numeric
patterns allows to use anti-recovery values such as &AA55AA55 and
&55AA55AA... Filling sectors with random data is also very useful for this
sort of things...
Obviously, using the military option is probably the best way to satisfy very
paranoid people (in particular -m -R which leaves no obvious sign of sectors
nuking)... I doubt they'll find this *enough* but I can't do much more than
this, sorry! :-)
The possibility to fill 'nuked' sectors with a user-defined string can be
useful to leave some funny message to the eventual curious... especially if
you *know* that someone will try to search for interesting text in the disc!
Since I think that nobody will use nuke, if you use it and/or if you find
some use for it, I will be really pleased to hear from you!
Notes
-----
nuke only works on E-Format discs (it would be useless to use nuke into an
image filing system, just nuke the whole image file!). nuke will not work on
the new version of FileCore that will be supplied with the Phoebe 2100 (or
whatever it will be called!) machine that Acorn will probably release in Q4
1998. You should absolutely avoid to run nuke on such a machine because it is
possible that it will actually corrupt a new format disc...
The option to nuke the free space can be useful only if you want to 'clean' a
disc (for example before selling it) but the files/directories-nuke should be
better for 'everyday use' (!). In fact, overwriting all the free space can be
a long operation (especially if the disc is mostly empty).
If nuke is stopped while it is working it may happen that you still have the
files and the directories but they are already overwritten: in fact, nuke
fills the sectors and then removes the files using a common 'wipe' command.
Disclaimer
----------
nuke has been tested and always worked perfectly. Anyway, if it becomes crazy
and it starts overwriting random sectors, I am sorry but I accept no
responsibility for that! Use it at your own risk.
History
-------
1.00 -- 28 Nov 94
First released version.
1.01a -- 07 Sep 95
Added support for 'big' discs.
1.01b -- 07 Jun 98
Added numeric pattern and random sector fill.
1.01c -- 12 Jun 98
1.01d -- 14 Jun 98
Added 'military' option.
Thanks go to:
-------------
- Cristian Ghezzi for the idea to 'nuke' the free space
- Julian Wright that recommended me to include the option to overwrite the
sectors more than once and found a use for it...
- Tony Hopstaken for paranoid suggestions and Nat Queen for even more
paranoid suggestions! ;-)
Conditions of use
-----------------
nuke is FreeWare: you can use and distribute it freely, provided that the
whole archive is copied unaltered (including this help file).
Contacting the Author
---------------------
Post: Sergio Monesi
Via Trento e Trieste 30
20046 Biassono (MI)
Italy
EMail: msergio@tin.it
pel0015@cdc8g5.cdc.polimi.it
sergio@freebsd.first.gmd.de
WWW: http://bounce.to/sergio/
(bouncing to http://www.alphawave.ltd.uk/sergio/ at the time of writing)