A Brief History of Memory
Electronic memory has been essential since the beginning of electronics. Virtually no logical or mathematical function can be implemented without some storage elements.
We will omit the history of electronic memory prior to integrated circuits (ICs), as this itself could fill a book. The first integrated memories, other than perhaps registers, were programmable read-only memory (PROM). Static random access memory (SRAM) devices soon followed PROMs. Dynamic random access memory (DRAMs) proved to be tricky to implement. Several companies tried 1T DRAM, but the first successful DRAM was the Intel 1103 3T DRAM. Within a few years, 1T DRAM appeared. This is the DRAM with which we are now very familiar, which dominates the entire volatile memory market. Figure 12.1 shows the evolution of memory. The evolution of DRAM is shown in Fig. 12.2.
Today’s systems contain many more memory chips than processor chips. Even the processor chips themselves contain large numbers...