Digital Electronics: Principles, Devices and Applications

15

Computer Fundamentals

This chapter focuses mainly on computer hardware fundamentals, with a brief introduction to some of the relevant software-related topics. The chapter begins with a brief description of different types of computer system, from giant supercomputers to tiny digital assistants, which is then followed up by anatomical description of a generalized computer system, with particular reference to microcomputer systems. Other hardware-related topics that are extensively covered include input/output devices and memory devices.

15.1 Anatomy of a Computer

The basic functional blocks of a computer comprise the central processing unit (CPU), memory and input and output ports. These functional blocks are depicted in the block schematic arrangement of Fig. 15.1. As is clear from the figure, these functional blocks are connected to each other by internal buses. The CPU is the brain of the computer. It is basically a microprocessor with associated circuits. Ports are physical interfaces on the computer, through which the computer interacts with the input and output devices. Memories are storage devices used for storing data and instructions. The CPU fetches the data and instructions by sending the address of the memory location on the address bus. The data and the instructions are then transferred to the CPU by the data bus. The CPU then executes the instructions and stores the processed data in the memory or sends them to an output device via the data bus. It may be mentioned ...