Computer System

Introduction

A computer is an electronic device that can be programmed to accept data (input), process it and generate result (output). A computer along with additional hardware and software together is called a computer system.

A computer system primarily comprises a central processing unit (CPU), memory, input/output devices and storage devices. All these components function together as a single unit to deliver the desired output.

Central Processing Unit (CPU)

It is the electronic circuitry of a computer that carries out the actual processing and usually referred as the brain of the computer. It is commonly called processor also. Physically, a CPU can be placed on one or more microchips called integrated circuits (IC). The ICs comprise semiconductor materials.

The CPU is given instructions and data through programs. The CPU then fetches the program and data from the memory and performs arithmetic and logic operations as per the given instructions and stores the result back to memory.

The CPU has two main components — Arithmetic Logic Unit (ALU) and Control Unit (CU). ALU performs all the arithmetic and logic operations that need to be done as per the instruction in a program. CU controls sequential instruction execution, interprets instructions and guides data flow through the computer’s memory, ALU and input or output devices.

Input Devices

The devices through which control signals are sent to a computer are termed as input devices.

These devices convert the input data into a digital form that is acceptable by the computer system. Some examples of input devices include keyboard, mouse, scanner, touch screen, etc., as shown in Figure.

Data entered through input device is temporarily stored in the main memory (also called RAM) of the computer system. For permanent storage and future use, the data, as well as instructions, are stored permanently in additional storage locations called secondary memory.

Output Devices

The device that receives data from a computer system for display, physical production, etc., is called output device. It converts digital information into a human understandable form. For example, monitor, projector, headphone, speaker, printer, etc.

Evolution of Computer

From the simple calculator to a modern-day powerful data processor, computing devices have evolved in a relatively short period. The evolution of computing devices is shown through a timeline in Figure. (Abacus to the integrated circuit)

Work in progress