I am in the proces of retiring a brace of old pcs from (office) work and need to delete the data in such a way that is is completely irrecoverable. Apart from reformating the HDD a few times, is there any software I can use so this process can be done in a controlled fashion?

Physical destruction – and it’s fun to do!

If you don’t want to destroy the HDDs

http://www.objmedia.demon.co.uk/freeSoftware/secureDelete.html

yes it’s a nice piece free under linux, get a free knoppix iso and google further

Darik’s Boot And Nuke is pretty much the standard way to do this.
It creates a bootable disk that will thoroughly wipe a hard drive.

Thanks guys.

If you mean completely irrecoverable, then standard utilities like those mentioned aren’t sufficient. At best they’ll just do a single pass over the disc, and standard rule of thumb is that you need 5 passes of random data (or 30 passes of non-random data – ie zeros) to make the data totally irrecoverable. That or heating the disc to a very high temperature.

aracer:

DBAN is configurable. It supports the multiple passes using randomly generated data or can be set to use the Guttman method which performs 35 passes.

Yup, I was going to say there’s free utilities that do dozens of passes, including random numbers, 1s and 0s etc. "They" reckon its perfectly easy to extract info even after 7 passes. If your business is so secretive (or has data that is so important) that it absolutely cannot be risked, just put the drives in a big bonfire.

It is all highly confidential so maybe the hammer method may be best but I’ll have a go at the utils method too….just for future reference.