Colin Jackson has posted a transcript of his latest regular National Radio technology chat. This week it’s a look at hard drives and how they work. It’s an interesting read:
Think of the disc surface as being made of the same substance as the surface of a cassette tape, or a video tape. It’s a magnetic film which you can magnetise one way or the other — either North pole up and South pole down, or vice versa. It gets magnetised by a tiny electric coil called a read/write head that floats just above the disc surface. The same head is used to detect how the disc is magnetised, as well.
When I used to teach beginner computer classes I’d take in an old disc drive and show them the platters and the arm, old sticks of RAM and whatnot. It made all that abstract talk about megabytes and storage so much more real.