Secure Destruction of HD's

[Guden Oden]

Writing random bits to the drive isn't effective, it takes AGES to do on a large harddrive, and I read once some NASA guy or such was quoted as saying even rewriting the drive 12 times allowed data to be extracted from it. Now, if they openly admitted to handling that many re-writes, they can probably handle a lot more... Imagine having to rewrite your 250GB harddrive 50+ times to be sure? (Because we sure seem to be paranoid here today, hehehe)

It would take half of forever!

Low-level formatting isn't possible on today's harddrives btw, as they have stuff like firmware, embedded servo information, sector IDs, spare sectors etc written to the disks that must not be overwritten. The drive just politely ignores any requests to low-level format.

Better to smash it up instead to be really sure.

 

[Sabastian]

Writing random bits to the drive isn't effective, it takes AGES to do on a large harddrive, and I read once some NASA guy or such was quoted as saying even rewriting the drive 12 times allowed data to be extracted from it. Now, if they openly admitted to handling that many re-writes, they can probably handle a lot more... Imagine having to rewrite your 250GB harddrive 50+ times to be sure? (Because we sure seem to be paranoid here today, hehehe)

It would take half of forever!

Low-level formatting isn't possible on today's harddrives btw, as they have stuff like firmware, embedded servo information, sector IDs, spare sectors etc written to the disks that must not be overwritten. The drive just politely ignores any requests to low-level format.

Better to smash it up instead to be really sure.

The software I have used doesn't do random bits.. it does every one and yes it does take a long time. The most passes it will do is IIRC about 3. The matter with Low level formatting was something I wasn't familiar with. I only did it once sometime ago on an old HD so what you say is likely the case with regards.

EDIT:Now I remember ... yeah, software like diskwipe doesn't prevent the retrieval of info from the HD by people using advanced information recovery but it will keep information from being discovered by people using software or "keyboard" type attacks. Which would prevent the vast majority of hackers from cherry picking info off it.

 

[Dio]

"dead dead dead" implies that they are totally unresponsive.. sorry for that. In which case a very strong magnet layed directly on the plates would do a number on the data.

Yes, if I can reformat them I'm not bothered.

Having managed to dismantle one of them, I found that - highly conveniently - the stepper motor is composed of one moving arm and two incredibly powerful magnets (capable of inflicting enough pressure to be uncomfortable when they are on either side of your palm)!. So those were used to thoroughly erase those two platters

 

[Guden Oden]

The software I have used doesn't do random bits.. it does every one

I didn't say it did random bits. Read more carefully, please. Leads to less confusion on all parties that way.

Anyway, if the idea is to thwart "hackers" and such, then using a disk edit tool or such to fill the entire harddrive with ANY value will make it "safe" (or you could do a plain DOS format or such, one that rewrites all sectors, and not just the basic file tree structure). As long as the file information is wiped, you can't retrieve it again when using the harddrive itself as the tool to do it with.