Erik> Hey all, I've got a DEC Alpha system that I can grab from work Erik> but not until I clean off the hard drives. Erik> It's a really nice system (server tower plus expansion, tons of Erik> docs and disks, etc.) that I'd like to make available at the Erik> VCF. Erik> The question is: how do I clean the drives completely without Erik> any real chance of data being recovered? The only other option Erik> would be to leave the drives behind so they can be crushed. Erik> I don't really know VMS and I'm not sure what versions are Erik> available, etc. I don't remember enough VMS DCL. But back in those days, there usually was an INITIALIZE command to put a new file system on a disk. And since disks typically had flaws that would be mapped around in the field (as opposed to at the factory, or in disk controller microcode) there were options to have it do a full disk surface scan. (On RSTS, which also uses DCL but doesn't always match VMS syntax, there's an EXERCISE switch that asks for that.) If you do a full scan, that writes every block with a test pattern, which blows away all the customer data. So try "HELP INITIALIZE" for hints. paul

Depends on what kind of adversary you're trying to defeat. If you don't care about someone opening the drive up in a cleanroom and using an atomic force microscope or its ilk on the platters, just write something meaningless (all zeros, for example) over the whole drive. If you do, buy a new drive and melt or vaporize the old one (thermite, plasma torch, whatever). You don't need to stick to VMS; for example, you could boot the NetBSD install floppies/CD and then shell out to, eg, dd /dev/zero onto the disk. /~\ The ASCII der Mouse \ / Ribbon Campaign X Against HTML mouse at rodents.montreal.qc.ca / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B

Erik Klein wrote: Depends on the level of paranoia. How sensitive is the date, and who are you trying to protect it from? For some, "delete [*...]*.*;*" is enough. However, there are some undelete programs, and you can still look at the raw disk to trace out some data, so this is not very secure. "delete/erase" is better, but doesn't wipe the entire disk, it only erases current files, not previously deleted files. The next level would be "init", which isn't much better than a plain "delete", or "init/erase" which actually damages the data. If it was erased with a simple pattern (zeroes), then the disk platters could be put into a special device that looks at magnetic levels (erasing a 1 leaves a slightly different residual than erasing a 0), or looks at the edge of the tracks to see if the head alignment changed enough to leave data there. Using a degauser is only likely to make the disks unusable to you, but may leave enough for the "black hats" to work with. You also need to worry about any cache built into the drives. Some drives have a battery backed up cache, in case the drive is powered down before it has a chance to write it to the platters. Melting the drives is more likely to perminately erase the data. The more paranoid you are about the data getting out, the more unlikely you are going to save the drives from a smelter.