I have a retro laptop from 1994, an IBM Thinkpad 340, which I want to give away, but first want to securely erase its deleted files.
The system contains both a GUI and CLI undelete
application, which lists previously deleted files and their respective chances for recovery according to how many clusters are intact.
I am looking for a solution like the cipher
or sdelete
on newer Windows systems to overwrite the empty disk portions with multiple zero/random write passes with tools built into stock Windows 3.1 with DOS 6.22.
I want to avoid having to install anything extra or booting a maintenance OS from floppy disk, as I have no easy data interface to that retro device at hand: No networking on the retro laptop, no floppy disks on any of my current devices, and I want to avoid buying a USB floppy drive.
If I get no software solution or no USB floppy drive, I’d have to resort to a hardware solution: Disassemble the retro laptop. Get the hard disk drive out. Connect the hard disk drive via my USB-ATA/IDE bridge (adapter/converter) to a host computer with the tools of my choice. But I'd like to avoid such an invasive operation with that luckily still functional retro laptop.
Google yields no useful software utility infos on those legacy pre-WWW systems. I'd appreciate a hint from anyone with experiences in that old systems/devices!
This is how I solved my issue in practice
1) Overwrite with random data: I used File Manager to duplicate c:\windows\system
content into dummy directory c:\aa
several times plus some remainder data until File Manager
showed 0KB free
for c:\
. Then repeated delete-duplicate-cycles to achieve about 7 complete overwrites in total. Finally deleted the bogus directory. — Compliments to @KodyBrown
2) Overwrite with zeros: Bought a USB floppy (6€, 2nd hand) for my contemporary laptop and created a bootable floppy disk with KillDisk for DOS v4.1 (final version from 2008, no further development). Booted into KillDisk and wiped the unused disk space with zeros. This way any possible future data recovery attempts have a better chance finding valid instead of bogus data. For confirmation I watched the raw disk data and the empty portions indeed were properly filled with null data (0x00
).
Nevertheless I am still curious in the original theoretical issue
For geek pride and other interested users without a floppy drive. I still would appreciate a working DOS 6.22 shell script which can properly fill the disk remainder with several random data passes and a final null data pass. Am offering to test it and give feedback. In the use case one has no data interface to the retro device (no network, no floppy) and thus has to manually type it in. Reminding of the microcomputer days in the 1980ies with source code in computer magazines. Charming! ;-)
.bat
is not one of those I can speak with.yes>o
might do.cat
instead ofyes
?