[comp.sys.mac] hard disk life

newton@nodename.dec.com (06/03/89)

Unlike most floppy drives, hard drives spin continuously when turned on.  Their
heads do not contact the media, but "fly" above the platters due to aerodynamic
effects.  Spinning the drives down would make the heads land or crash - and the
average drive speed would plummet if the platters had to be revved up each time
the computer wanted to access the disk.