Unit 3

Parts of a Computer

 

3   3.1   The Basic Operations of Computer

5 Basic Operations of a Computer System

1. Processing
2. Outputting
3. Storing
4. Controlling

Input Unit

Inputting is a basic operation of a computer system. This is the act of feeding in the data and instruction to the computer (by computer here it means the processing unit).

A computer system consists of different functional units and Input Unit does the operation of Inputting. By inputting you should understand that it is to send data and/or instruction to computer in required format.

Information and programs are entered into the computer through Input devices such as the keyboard, disks, or through other computers via network connections or modems connected to the Internet. The input device also retrieves information off disks.

The devices that helps you to input data and instructions are known as Input Devices. Keyboard, Mouse, Light Pen, JoyStick, Scanners, Microphone etc are some examples of input unit devices.

Processing Unit

The task of performing calculations and comparisons are known as processing. The unit in Computer System that is responsible for processing is ALU (Arithmetic and Logical Unit).

ALU is the place where actual execution of the instructions takes place during the processing operations. All calculations & comparisons are made in the ALU. The data and instructions stored in the primary storage are transferred to it as when required. ALU may produce Intermediate results and store it in the memory which are also transferred back to the ALU for the final processing. After completion of processing the final results are send to storage units from ALU.

Output Unit

This unit takes care of receiving processed information from processing unit and present it to the user in suitable form. A computer produces results in binary form and output unit does decoding to make it usable to the users.

The devices that can output information from computer are known as output unit devices. Monitors, Speakers, Projectors are soft output devices whereas printers, plotters produces hard copy output.

Softcopy output is something that is temporary or is available only as long as output device is turned on. Contrary to these are hard copy output which are permanent. The printout in a paper is not lost because printer is turned off!

Storage Unit

Before actual processing start, data & instructions entered to the computer must be stored somewhere inside the computer. Similarly, results produced by the computer are required to be stored before it is passed to the output unit. The intermediate result produced by the computer must also be stored for further processing. Thus the importance of storage Unit in a computer system is vital.

Based on whether storage device is inside the main machine or not, it can be internal internal or external storage. Similarly, looking at whether the storage device works close with CPU or works as backup media, they can be primary storage or secondary storage. Primary storage are also called primary memory. Secondary storage are known with other names such as backup storage or secondary memory.

For the storage purpose, a computer system may have different devices such as registers, cache, RAM/ROM, flash, magnetic disks, optical disks and so on.

Control Unit

ALU dose not know what should be done with the data likewise, output unit dose not know when the result should be displayed. By selecting, interning and seeing to the execution of the program the CU is able to maintain order and direct the operations of the entire system. CU doesn’t perform any actual processing on data yet it is known as a central nervous system for the comforts of the computer.