Re: What no-one has mentioned yet... - DRUMS
Less common than disks were drums - metal lumps about the size of washing machine drums coated with magnetic oxide and an array of fixed heads - one per track. They were faster than disks because there was no seek time.
Some of these could weigh 60lbs and rotate at 3000rpm. A story that I heard (but could not verify) was that on one of these a bearing failed and the drum departed from the mechanism at speed and left a trail of destruction before it finally came to rest.