Essential Computer Concepts

History of Computers• Charles Babbage - father of computer

– 1800’s planned analytical engine

• ENIAC - developed at end of WW II• 1951 - 1963 1st and 2nd generation

– very large, used unreliable vacuum tubes

• 1963 - present - 3rd and 4th generation– smaller, faster - use transistors and integrated

circuits

2

History - Microcomputers

• Apple– First sold in late 1970’s – Developed by Jobs and Wozniak

• IBM Personal Computers– First sold in 1981– Was quickly accepted by businesses– IBM compatibles soon developed

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What Is a Computer?

• A computer is an electronic device that accepts data and instructions from a user, manipulates the data according to the instructions, displays the information in some way, and stores the information for retrieval later

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What is a computer?

• An electronic device that accepts input,

processes the data and instructions, produces

output from the processing that is useful and

meaningful and stores the results for future use.

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How Does A Computer Know What To Do?

• It must be given a detailed set of instructions that tell it exactly what to do.

• These instructions are called a computer program, or software.

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How Does A Computer Know What To Do?

• It must be given a detailed set of instructions that tell it exactly what to do.

• These instructions are called a computer program, or software.

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1st Generation Of Computer

2nd Generation Of Computer

3rd Generation Of Computer

4th Generation Of Computer

5th Generation Of Computer

The term Computer Generation is after use in relation to the hard were of computer. Each phase of computer development is known as separate generation of computer. Each phase of development is characterized by type of switching circuits it utilizes.

Most computer today use the idea of stored program. Computer that was proposed by Dr.John Von Neumann in 1945.The Von Neumann architecture is based in three key concept that are:

1)Data & instruction (program) are stored in a single read write memory.

2)The memory content are addressable by location.3)Execution takes place in sequential fashion.

[1949-55]• The first generation of computer used the

vaccume tube & machine language was used for giving instruction. The first generation computer used the concept ‘stored program'. The computer of this generation were very large in size & their programming was a difficult task.

Some computer of this generation are given below:

• ENIAC :-It has very small memory & it was used for calculating trajectories of missiles.

• EDVAC:-The “Von Newmann” concept of stored program, was also applied in EDVAC.

Some key feature of first generation:

• Used vaccume tubes.

• Big computers.

• Electrically consumption high.

• Large Ac’s were necessary because the computer

generated heat.

1956-65• The second generation computer began

with the advent transistorized circuitry, invention of magnetic core & development of magnetic disk storage devicer.These new development made these computer more reliable. These Industries in the application’s like Marketing, Production planning etc.

Some key feature of second generation:

• Transistor replaced vaccume tubes.

• Small in size.

• Less amount of heat was generated.

• Core memory was developed.

• First operating system was developed.

• Programming was in machine language as well as assembly language.

[1966-1975]The third generation of computer replaced

transister with ‘Integrated circuits’ popularly known as chips. The IC was inverted by Jack kilby at Texas Instrument in 1958.The third generation computer using integrated circuit Proved to be highly reliable,relatively expensive & faster.

Some key feature of third generation:

• Integrated circuits developed.

• Power consumption was low.

• Computer were smaller, faster & more

reliable.

• High level languages (HLL) appeared.

[1976-Present]• The advent of the microprocessor chip marked the

beginning of the fourth generation computer. Very Large Scale Integrated (VLSI) circuits packing about 50,000 transistor in a chip. The Hard disks are also available of the size up to 80 GB.For larger disks RAID technology give to storage hundreds of GB. The CD ROM also becoming popular day by day. The CD ROM of today can store up to 650 MBS information.

Some key features of forth generation:

• Integrated circuits smaller & faster.

• Portable computer developed.

• Great development in data communication.

• Different types of secondary memory with high

storage capacity & fast access developed.

[Coming Generation]Fifth Generation computing devices based on

artificial intelligence, are still in development. The goal of fifth generation computing is to develop devices that response to natural language input & are capable of learning & self organization.

Some key features of fifth generation:

• Parallel Processing was done.• Super conductors were used.• Many processors are grouped to function as one

large group processor.• A super conductor is a conductor through which

electricity can travel without any resistance resulting in faster transfer of information between the components of computer.