02-27-1993

This is a short program I wrote that deletes a file, and if you undelete it,
it does not contain the original information. Wildcards are not allowed. You
can only kill one file at a time. Just type "D", and then you name the file to
be destroyed.

Now, the only reason I can think of for you to use this utility is to get rid
of a file fast if it's top-secret. A normal "Del" or "Erase" command will only
pluck out the leading character of the file's first name, thereby making it
invisible to DOS at the F.A.T. level. The file is still there on disk, it's
just that DOS doesn't know this. The file is un-deletable with a number of un-
delete utilities available today. But, if you happen to write to the same sub-
directory, chances are that maybe you'll hit the deleted file and corrupt it,
making total un-deletion impossible. If you write to that same sub-directory
with a file of the same exact name as the deleted file, then only a seasoned
programmer with a sector editing utility stands any hope of recovering even a
little bit of the data in the deleted file. And it takes a while, too. With my
program, you create a garbage file at least as long as the deleted one, and
possibly up to 80 bytes longer for good measure. It has the same path and file
name. Then it deletes it. And my program also does not open the original file
for output, making for less opportunity for DOS to randomize where it might
decide to write next ("where the wind wills"). Try it, if you like it let me
know.

Programmers: You may understand my concepts. If there are any errors or
improvements you can point out, definitely mail them to me. Also, if anyone
"busts" it, i.e. if you can still recover a substantial amount of the original
data from the original file, definitely mail me your results. (And anything
else you can think of for the benefit of my research).

I have a utility by SoftLogic Solutions called "KillFile" 4.05 which has the
same function, but I noticed that when I had Windows 3.1's Smartdrv write-
caching turned on, and used KillFile, that Smartdrv would not dump the write
to disk. The 5 second rule was suspended indefinitely. But exit KillFile, and
Smartdrv dumped immediately. With my program, the write goes down within 5
seconds. With Smartdrv for Windows 3.1, with write-caching on, a small cache,
and some big files "kill", and a person could run their computer out of
memory... not a problem with my program.


Duane Bailey                                              My handle: "Yes Fan"
409 W. First St, Apt. C
Winston-Salem, NC 27101