Random-access memory - Wikipedia
https://en.wikipedia.org/wiki/Random-access_memoryEarly computers used relays, mechanical counters or delay lines for main memory functions. Ultrasonic delay lines were serial devices which could only reproduce data in the order it was written. Drum memory could be expanded at relatively low cost but efficient retrieval of memory items required knowledge of the physical layout of the drum to optimize speed. Latches built out of vacuum tube triodes, a…
Random-access memory - Wikipedia
en.wikipedia.org › wiki › Random-access_memory[1] [2] a random-access memory device allows data items to be read or written in almost the same amount of time irrespective of the physical location of data inside the memory, in contrast with other direct-access data storage media (such as hard disks, cd-rws, dvd-rws and the older magnetic tapes and drum memory ), where the time required to …