Hard drive erasing?

[mole42uk]

I am proposing to sell a couple of old Macintosh computers which do not start up. I want to ensure that the hard drives are erased before I do so.

Is there any way of doing this without removing the drives and powering them up an an alternative machine? Would the application of a neodymium magnet work?

[Radio Wrangler]

Waving a neodymium magnet around outside them is unlikely to work because they already have such thinga inside them.

The time-consuming approach to security involves firing up the drives in another machine, not just telling it to delete the files because that just clears the index, but also to overwrite the drive to full capacity.

The quick alternative involves a large hammer.

David

[paulsherwin]

Probably not, as the drives are screened. It certainly wouldn't be a reliable erasure. You will need to fit the drives in a different computer, or use a USB adaptor.

Considering forensic hard drive recovery costs a small fortune I wouldn't be concerned.

[paulsherwin]

You do need to overwrite the disk if you're concerned about the contents, as it's relatively easy to recover files from a drive if they've just been 'deleted', or even if the partition table has been overwritten.

I agree that there's no need for the really paranoid actions though - overwriting the drive with dozens of passes, that sort of thing. There's no documented example of any data recovery organisation recovering real world data from a drive that has been overwritten with a single pass, even in laboratory conditions, and any commercial company would certainly publicise it if they could do it. Spooks like GCHQ and the NSA like to imply that they can do it, but that's really just psychological warfare.

[mole42uk]

I'm less concerned about the actual contents, rather more concerned that I have no idea what might be lurking on there...

[Radio Wrangler]

But, if you're going to sell a computer with them in it, and it's likely that the computer is going to be restored, then it would be likely that anything on the drives would come to light. File recovery software is easy to find to handle the case where the index is cleared.

Cheltenham and Fort Meade's probably fictitious capabilities would not be called on.

An over-write, or else the big hammer is called for. It just depends on whether you have an alternative machine to spin them up and the criticality of what you think may be on them.

The same thing goes for flash drives in modern machines.

David

[paulsherwin]

Most old consumer HDs don't contain information of interest to anybody anyway. Who is interested in 5 year old eBay passwords or old email accounts? It's mainly an issue for public sector bodies and commercial companies, where releasing recoverable data will cause bad publicity and may violate data protection legislation.

[Refugee]

I can remember refurbishing ex government computers.
The quickest way was to un-format them and delete all the old files.
There was loads of stuff to peep at.
Still it was quicker than installing windows.

[OldTechFan96]

Originally Posted by mole42uk

I am proposing to sell a couple of old Macintosh computers which do not start up. I want to ensure that the hard drives are erased before I do so.

What models? A boot floppy/CD with Apple Disk Tools should do the job.

[Paul Stenning]

One consideration is how large the hard disk is. Anything under 500GB is of minimal use or value now (they sell for under £10), so just destroy it with a large hammer and don't waste any more time on it.

If it is larger (especially 1TB or more) then it is worth doing a single-pass overwrite to erase everything so that it cannot be "un-erased" or recovered. There are a few boot disks to do this.

For PCs, Darik's Boot and Nuke which don't need a running operating system is a good choice https://sourceforge.net/projects/dban/. I don't know what options are available for Apple.

[AC/HL]

Killdisk: https://www.killdisk.com/eraser.html
You do need a working PC for any method though.

[mole42uk]

Both drives are small, less than 500Mb, and both are SCSI which is an interface I can't use anymore, so the hammer is going to be the solution.....

Thanks all for the comments.

[Dual Standard]

Originally Posted by Radio Wrangler

The time-consuming approach to security involves firing up the drives in another machine, not just telling it to delete the files because that just clears the index, but also to overwrite the drive to full capacity.

The quick alternative involves a large hammer.

David

40+ years working in IT, mostly in customers as a 'fly on the wall', tells me that David right.
A pick axe is my weapon of choice but a large hammer will be fine too.

Mike

[paulsherwin]

If you just break off the connector with a pair of pliers you immediately put the drive into the 'professional data recovery required' category, which almost nobody is going to pay to have done.

[OldTechFan96]

They would be useful to collectors of Apple computers. Don't smash them up. I could erase them if you want.

My Macintosh SE/30 has been without a HDD for five years!

[paulsherwin]

There's no shortage of small 50 pin SCSI drives though. If you ask on here, somebody is likely to have one in the junk box. You can use the later 68 pin or SCA drives with a £5 adaptor.

[AC/HL]

If you are going to scrap them, unless you've done it before stripping one down is quite interesting. Only the magnet is of any use, but the platters make good bird scarers.

[TonyDuell]

It depends on whether you want the drive to be useable afterwards. Using an external magnet or AC magnetic field will ruin the drive as it will erase the factory-written servo information on the disk. The only way to rewrite this involves a special positioner jig (I belive using a laser interferometer as the position transducter!) in a clean room.

I am rather worried about the 'small old drives are worthless' attitude here. Many drive with 'legacy' interfaces are getting very hard to find now (even the once-common ST412 interface (aka ST506, MFM, etc) is rare now). You can't always replace the interface card and use a SATA drive (try that on a PERQ, PDP11, Whitechapel MG1, etc and you have many months of work ahead of you). You don't say 'Oh, the UL41 output valve is worthless, a KT88 will give you a lot more power' do you?

Unless there is something seriously secret on the drives I would suggest just overwriting the data and reformatting. Yes a government agency could probably recover the data. But most computer enthusiasts won't bother. They just want a drive to put their data on.

[G4_Pete]

Take care if you dismantle the drives , some have glass platters which seem to be stressed in that they can break explosivly spreading glass over a several feet. I learnt this to my cost and got cut in the process.
Pete