The variety of memory used for computers is amazing, and I find it a lot more interesting than the history of the CPU. CPU architecture is very diverse, but physically tends to be just different configurations of a few physical elements - relay, valve or transistor.
Memory had cathode ray tubes, mercury delay lines, dekatron and selectron tubes, core store, core rope, magnetic drums, tapes and discs, magnetostrictive delay lines, magneto-optical discs, and probably many more I don't know about, not counting the write-once formats like punched card and tape.
Memory had cathode ray tubes, mercury delay lines, dekatron and selectron tubes, core store, core rope, magnetic drums, tapes and discs, magnetostrictive delay lines, magneto-optical discs, and probably many more I don't know about, not counting the write-once formats like punched card and tape.