My first job in aerospace was designing a SRAM card to use in place of UVEPROM so the software guys could download code and not have to keep burning/erasing UVEPROM boards. Whopping 320K bytes. 2nd task was updating that to 768Kbytes and adding 32K of EEPROM.
Also ran on a 20 address-bit ROLM bus with 2910 bit slice processor, 110nS cycle times to receive the address and the read/write control, decode if it was for the card, and have data back out on the bus. Had 4 or 5 memory cards in the system, plus other cards that responded on the same bus. 21st address bit added later on.
Eventually all the memory was pulled back into a single processor card with an intel processor.