Computer The word computer comes from the word“compute’’ which means “to calculate’’. Hence Computer to be a calculating devicethat can perform arithmetic operations at highspeed.A computer is an electronic device whichProcesses information based upon theinstructions provided the deseire output.acomputer can store processes and retrieve data asand when desired.

Characterstics of computer

• Automatic machine.• High speed.• Accuracy• Versatile• Storing• Deligence

Limitation of computer

• No IQ• No feelings• No learning capacity• Human dependent• Hardware and software

dependent

Computer generations• Computer generation is a step in

technology. It provides a framework for the growth of computer. it has now extend to include both hardware and software to make a computer system

1st GENRATION(1942-1945)

• These machine use thousands of vacuum tubes

• These vacuum tube are made up of fragile glass device which used filaments as a source of electronics and could control the electronic signals.

2nd GENERATION(1955-1962)

• In this new electronic devices are invented that must called transistors.

• These were more powerful • Less expensive.• They use magnetic disk and tape as a

secondary storage medium.• High-level languages were used in second

genration

3rd generation(1964-1975)

• In this integrated circuits are used.• The were smaller and less expensive.• Consumed less power and produced less heat.• Mini computers were used.• Time sharing operating system were invented

in this generation.

4th generation(1975-1989)

• In this micro processor were used.• Faster smaller and less power consuming then

third generation.• They were general purpose machine.• Graphical user interface used.• hey were use in hTomes and as for personal

use of an human being.

5th generation.(1989-present)

• This generation increase the power of micro processor chip.

• VLSI technology become ULSI.• More user friendly.• Large primary storage capacity.• Provide network facility(lan,man ,wan)

Basic function of computer

• Inputting • Storing• Processing• Outputting• controlling