March 13, 2011 04:55 PM

Some time in the last century, a neighbour asked whether I'd be able to help out the owner of a local independent video rental shop - whose computer "wouldn't turn on".

The machine itself was unremarkable - an IBM PC clone, running DOS. Or rather, it would have been running DOS if it could see its hard drive, which it couldn't. Suspecting a loose cable, I popped the cover to take a peek at the 3.5" full height drive. Rodime; 20Mbytes; ST506 interface - exactly the same make and model as my own system at the time.

My personal drive dated back to my student days - bought at a local computer auction, I'd assumed that's why on very cold days it would need to have its platter manually rotated before it would spin up.

The shopkeeper had no idea what I was talking about when I explained this. Nor any idea what backups were, whether he'd ever had any, and could I just make it work please because he couldn't run his business without it.

This is the point where it's sensible simply to offer one's condolences, and move on. So, naturally, I set about removing the drive from the PC and pointing out the drive motor controller chip's resemblance to well done toast. This was a very, very, dead drive. Time to leave. Unless …

The following lunchtime I returned with the drive, and some trepidation. I'd swapped the carbonised circuit board with mine, and it had successfully powered up. I wasn't insane enough to try to connect the zombie drive's data cables to my own system, so wasn't really expecting this to work …

Beep … DOS … "XYZ Video Rental Software".

I followed a few of the menu options, and incredibly, it appeared the entire system was there. All the customers. All the videotapes. All the customers' videotapes' overdue fees.

"What do I owe you?"

"How about - free video rental forever?"

"Nah, can't do that".

"Sure you can - look - there's an option for it here".

"Nah, can't do that".

I shrugged my shoulders and left. The video store closed the following year.

Epilogue:

Hard drives are surprisingly resilient, but - like Roger Rabbit's handcuffs - only when it's funny. While a gentle tap can send the heads scudding across the platter, trashing all your data, hurling a hard drive in a skip could end with your documents and settings on eBay.

A pair of tools that are perfect when passing on your platters are Darik's Boot And Nuke and Mark Russinovich's sdelete.

The former is a standalone solution - download, burn to CDROM, and for safety's sake, boot from a computer containing only the drive you want to wipe. Are you sure? Are you really, *really* sure?

The latter is an excellent utility when you're returning a borrowed computer (or handing back your work laptop when heading for pastures new). Having deleted anything you don't want to pass on, sdelete's "clean free space" option makes sure it can't be undeleted again. While not quite as drastic as dban, it saves you (or your hapless sysadmin) the chore of re-installing an operating system.