Thu, 12 Jul 2007
Dissecting a Hard Drive
In order to teach Iva something about computers (and, of course, out of my own curiosity), I brought a broken IBM 180 GB HDD home, and we have tried to dismantle it.
There was almost no surprise for me. The inner space of the drive was pretty simple and cleanly designed. Even the screws were almost uniform, with only two types of head used (Torx-10 and Torx-15). The interesting parts were the following:
- A magic smoke container (err, a silica-gel bag :-). Why they put a short-term lasting dessicant inside, when the drive is expected to live for three or more years?
- The motor is synchronous (commutator-less) four-point device, so it can be usable for hardware hacks as a stepper motor, but unfortunately not as a general motor without an additional circuitry. When I tried to rotate it by hand, in one direction it was much easier than in the other one. Can anybody explain this?
- Probably the most interesting parts were permanent magnets which are used for head movement. There are two small plates (about 1-2mm thick, maybe 4x1cm area) mounted to steel brackets, which are not tied together by anything else than the force of the magnets. And the magneds were strong: when playing with them we have accidentally put both magnets on top of each other, and I had hard time splitting them apart again. Anyone can think of a novel project with these magnets?
Our future project is to get an older drive and compare how the technology has advanced over the years.
3 replies for this story:
Věroš wrote: Magnets
Great idea, I need two magnets to emulate locking on my car's fuel tank. Going to disassemble some old hard drives.
misch wrote: magnets
They are probably Neodymium or SmCo (Samarium-Cobalt) magnets. Don't try to stick larger magnets of this kind to your refrigerator, thery are really strong, and you will have a hard time removing them! :-) BTW: There is a magnet-shop named 'rootra' in Prague (http://www.rootra.com/), where some people buy strong but small magnets for microcaches. Alas, no such shop in Brno, AFAIK.
Stepan wrote: magnets (again)
In Brno, you can buy Neodyms at Selos, see http://magnety.selos.cz/index.php?sekcia=produkty&idp=59 You can see small examplet at http://www.volny.cz/neodymmagnet/