Memory Systems

As shown in Figure 1.1, a computing system consists of three fundamental units: (i) units of computation to perform operations on data (e.g., processors, as we have seen in a previous chapter), (ii) units of storage (or memory) that store data to be operated on or archived, (iii) units of communication that communicate data between computation units and storage units. The storage/memory units are usually categorized into two: (i) memory system, which acts as a working storage area, storing the data that is currently being operated on by the running programs, and (ii) the backup storage system, e.g., the hard disk, which acts as a backing store, storing data for a longer term in a persistent manner. This chapter will focus on the “working storage area” of the processor, i.e., the memory system.

The memory system is the repository of data from where data can be retrieved and updated by the processor (or processors). Throughout the operation of a computing system, the processor reads data from the memory system, performs computation on the data, and writes the modified data back into the memory system – continuously repeating this procedure until all the necessary computation has been performed on all the necessary data.