SysInternals SDelete

[AlephX]

Category: Mass Storage / Privacy

SysInternals SDelete v1.4
http://www.sysinternals.com/Utilities/SDelete.html


Synopsis:
SDelete cleans the free space on your disk and securely deletes also files and folders. SDelete is a command line utility that takes a number of options.

Usage: sdelete [-p passes] [-s] [-q] <file or directory>
sdelete [-p passes] -z [drive letter]

-p passes
Specifies number of overwrite passes
-s
Recurse subdirectories
-q
Don't print errors (quiet)
-z
Cleanse free space

The interesting feature is to indirectly overwrite free space. SDelete allocates the largest file it can and then securely deletes it.

Write settings to:
none

Usage:
unzip and copy to folder. Run sdelete.exe (in dos mode)
Unicode support:
no

space uncompressed:
62 Kb

License:
freeware
(Source code with permission)

greetings everybody!!!

[Andrew Lee]

Check out "Why don't you accept command-line apps?" under the FAQ?

[AlephX]

OOOps!

Ok, now I´ve realized that

Good point! You are right.

[webfork]

Old thread update: I just did some work posting about this before I found out that it wasn't helpful for one task, but along the way I noticed a few other things:

There is a way that it might qualify as portable: if you just drag and drop a file onto SDelete, it will automatically wipe the file (a 1x overwrite, which is all most users need).

More info on SDelete:
http://technet.microsoft.com/en-us/sysi ... 97443.aspx
https://www.pcworld.com/article/2024256 ... -line.html

Also, on the command line side, the zero out freespace wipe is a somewhat faster (and slightly less secure) option than a regular free space wipe. I haven't tested this at length but:

• If you wipe your computer frequently, it will take an order of magnitude LESS time if you only ever run a zero-out function like with SDelete. This is because it will skip any space you've already zero'd out that doesn't need further wiping.
• For high security types: you should generally speaking not use this on encrypted volumes, as it could make them fundamentally less secure. This is because the lack of entropy can create a more discernible pattern for cryptanalysis.

[guinness]

Interesting, learnt something today about SDelete.

[SYSTEM]

There is a way that it might qualify as portable: if you just drag and drop a file onto SDelete, it will automatically wipe the file (a 1x overwrite, which is all most users need).

BTW, it's a feature of Windows rather than SDelete. When you drag and drop a file on an executable, Windows launches the executable and gives the path of the file as a command-line parameter.

http://technet.microsoft.com/en-us/sysi ... 97443.aspx

The link is broken.

If you wipe your computer frequently, it will take an order of magnitude LESS time if you only ever run a zero-out function like with SDelete. This is because it will skip any space you've already zero'd out that doesn't need further wiping.

AFAIK, this isn't the reason why wiping with zeroes is faster. The reason is that generating random data takes time, and when wiping free space with random data, the processor needs to generate gigabytes of it.

[Midas]

AFAIK, this isn't the reason why wiping with zeroes is faster. The reason is that generating random data takes time, and when wiping free space with random data, the processor needs to generate gigabytes of it.

Enlightening. Thanks for sharing it, SYSTEM.

[webfork]

The link is broken.

That was weird ... will go back and edit those.

AFAIK, this isn't the reason why wiping with zeroes is faster. The reason is that generating random data takes time, and when wiping free space with random data, the processor needs to generate gigabytes of it.

Yeah, I discussed this with an engineer who indicated that if anything it would take more time to zero out a drive. A random number generator would of course take more processor juice but as the hard drive is the bottleneck on most computers, the read-then-write function of the zero-out process would end up more time-consuming. A good idea for a freeware program therefore would be something to track these areas that had already been zero'd and not check them again.