Contents of Main Memory

Main memory (as all computer memory) stores bit patterns. That is, each memory location consists of eight bits, and each bit is either "0" or "1". For example, the picture shows the first few bytes of memory.

The only thing that can be stored at one memory location is eight bits, each with a value of "0" or "1". The bits at a memory location are called the contents of that location.

Sometimes people will say that each memory location holds an eight bit binary number. This is OK, as long as you remember that the "number" might be used to represent a character, or anything else.

Remember that what a particular pattern represents depends on its context (ie., how a program is using it.) You cannot look at an arbitrary bit pattern (such as those in the picture) and say what it represents.