Handbook of Machine Design P55

The computer software is divisible into several modules in terms of function. Figure 47.14 shows the relationships of these modules. The monitor is a small program permanently stored in read-only memory (ROM) in the microcomputer. It performs basic traffic direction and boots up the supervisor. That is, when the computer is switched on, the monitor expects to find a program waiting to be read from a mass storage device. It initiates reading of this program, which is, in fact, the remainder of the permanent software. ...