Functions of computers

1. ASSIGNMENT NO. 1
INTRODUCTION TO COMPUTERS

2. Introduction to computers
• A Computer system is an Electronic data processing device, which
accepted and store an input data, process the input, and output the
processed data in the required format.
• Any digital computer carriers out five basic functions:
1. Takes data as Inputs.
2. Store the data / instructions in its memory and can use them when
required.
3. Proceed the data and covert it into useful information.
4. Output the information.
5. Control all the above four steps.

3. Characteristics Features of computers
• Speed.
• Storage.
• Accuracy.
• Versatility.
• Automation.
• Diligence.
• Networking capabilities.

4. Types of computers:
• PC (personal computer) : Single users computer system.
Moderately powerful microprocessor.
• Workstation : Single users computer system. Similar to
personal computer but have more powerful
microprocessor.
• Mini Computer : Multi users computer system. Capable of
supporting hundreds of users simultaneously.
• Main Frame Computer : Multi users computer system.
Capable of supporting hundreds of users simultaneously. Software
technology is different from mini computer.
• Super Computer : An extremely fast computer which can
perform hundreds of millions of instruction per second.

5. Functional Diagram of a computer :

6. Components of computers
The Computer Consist of the following basic components :
• Input Device
• Output Device
• CPU (central processing unit) :
1. Memory unit
2. Control unit
3. ALU (Arithmetic Logic Unit)
• Computer Memory :
• Primary Memory
• Secondary storage device

7. Components of computers : Input Devices
Devices that are uses to enter information and instructions into a
computerfor storage or processing are called input devices. The main
input devices of computer are :
• Keyboard
• Mouse
• Touchpad
• Trackball
• Touch screen
• Light pen
• Magnetic ink Character recognition (MICR)
• Barcode reader
• Optical Mark reader
• Scanner
• Microphone

8. Components of computers : Output Devices:
Output units Consist of devices with the help of which we get the
information from the computer. The main output devices of computer are:
• Monitor
• Printer
• Plotter
• Facsimile (FAX)
• Speaker

9. Components of computers: CPU :
CPU is considered as the brain of computer. CPU perform all types of data
processing operations. It stores data, intermediate results and instructions
program.
It (CPU) takes data and instructions from the storage unit and makes all
sorts of Calculation based on the instructions given and the type of data
provided.
CPU itself as the following three components :
• Memory Unit : This unit can store instructions, data and intermediate
results.
• Control Unit : This unit controls the operation of all parts of Computer. It
does not carry out any actual data processing operations.
• ALU ( Arithmetic Logic Unit ) : It performs arithmetic operations like
addition, substraction, multiplication & Division and logic Operations

10. Components of computers: Memory :
Secondary Memory/ Secondary storage devices :
• These includes devices that are peripheral and are connected and
controlled by the computers to enable permanent storage of programs
and data. Large files and databases are stored on Secondary storage
devices.
Secondary storage devices can be divided into:
1. Magnetic Storage devices:
• Floppy Disk
• Hard Drive
2. Optical storage devices:
• CD ROM
• DV ROM