The early Manchester computers (Baby and MU1) used modified CRTs to store the data in a RAM array. The technique (The Williams tube) was so successful it was used by IBM for serveral of their machines too

The early Cambridge machines (EDSAC) used long mercury filled tanks for acoustic delay lines, again storing data in shift registers

I wasn't there, my dad told me. In the early seventies I was at infants school...

Steve