Internal tech specs on old scsi hdds

[Ayman Altounji]

I recently had to destroy some old scsi drives taken from a VAX workstation used here at work. We were required to permanently wipe the contents of the drive, and to do this disassemble the drive and wave a magnet over the drive platters.

2 of the drives this was done to were full-height 5.25" scsi hdds, one 330MB and one 600MB. I don't have the exact model numbers, unfortunately. One drive was built by DEC, one by another maker, but very similar construction inside. Inside the drive, the mechanism that moves the read-write head was driven by a coiled wire (electromagnet) inside an enclosure with 2 rather powerful permanent magnets. It's a very interesting mechanism, and I've had some fun playing with it.

I was wondering if it would be possible to get some information on the types of magnets used, construction, materials, and that sort of thing.

Anyone able to give me some pointers or places to look?

Tim

[Ayman Altounji]

Don't have that kind of information available on them... Especially as old as they must be.

[Ayman Altounji]

The mechanism is a voice-coil actuator, so called because it moves the heads in a similar way to how the cone is moved in a speaker. It replaces the older stepper motor method of moving the read heads. All modern drives use voice coil actuators AFAIK.
Ray

[Ayman Altounji]

Voice coil mechanisms also have the nice feature of being auto-parking. When power is cut off, the drive heads move back to the landing zone. Something that's very handy.

Remember being admonished to use the "park" utilities before shutting down your old MFM/RLL hard drives?