Computer Science Class 6 Chapter-1 Evolution of Computers

 Overview of the chapter

• Different generations of computers
• First Generation: 1946-1958 (Vacuum Tubes)
• Second generation: 1959-1964 (Transistors)
• Third generation: 1965-1970 (Integrated Circuits IC)
• Fourth generation: 1971- today (Microprocessors)
• Categories of computers
  • On the basis of working principle
  • On the basis of size
  • On the basis of brand

Introduction

• Computer are such an integral part of our everyday life.
• Computer is an electronic machine which performs mathematics and logical calculations.
• Charles Babbage is called the Father of computer.
• Now, in this chapter, we are trying to describe the types of computers and elaborate classification of computer.
• Computers can be classified in various ways depending on their generation, working, size and use.

Generations of Computer

• The term ‘Generations’ means improvement in the development of a product (computer).
• Every new generation, the circuitry has gotten smaller and more advances than the previous generation.
• New discoveries are constantly being developed that effect the way of we live, work and play.

The first generation: 1946- 1958 (Vacuum Tubes)

• The I^st generation computers were huge, slow, expansive and often unreliable.
• In 1946 two Americans, Presper Eckert and John Mauchly built the ENIAC.
• ENIAC was made up of 18,000 vacuum tubes and occupied a 30 * 50 feet room.
• ENIAC stands for Electronic Numeric Integration and Calculator.

Key Features

• Vacuum tubes based, punched tape input or output, about 1,000 circuits per cubic foot.

Examples- ENIAC, IBM models 604,650(drum memory), 701,702,704,705,709 etc.

Things to remember: ENIAC was the world’s Ist successful electronic computer.

 

The Second generation: 1959-1964 (Transistors)

• As the development moved further, the second generation computer knocked the door.
• In 1947, three scientists, John Bardeen William Shockley and Walter Brattain working at AT & T’s Bell Labs invented transistor.
• It was faster, more reliable, smaller & much cheaper to build than a vacuum.
• One transistor replaced the equivalents of 40 vacuum tubes.
• The size of computer also decreased and it became much smaller than that of earlier computer.
• Therefore, they were very cheap to produce.

Key Features

• Low electricity consumption.
• Mare reliable and faster.
• Used transistors, about 1,00,000 circuits per foot.

Examples – UNIVAC – III, IBM 7070, 7080,7090,1400,1600 series etc…

Third generation: 1965-1970 (Integrated Circuits IC)

• Invented in the year 1965.
• In this generation of computer, IC (Integrated Circuits) was used as the electronic component for computers.
• The development of IC gave birth to a new felid of microelectronics.
• It is small in size, superior performance and reliability than the previous circuits.
• Robert Noyce of Fairchild Corporation & Jack Kilby of Texas Instruments discovered the integrated circuits.

Key Features

• Low power consumption.
• Large scale IC, 10 million circuits per square foot.

Examples – IBM 360 series, GE 235 etc…

The Fourth generation: 1971- today (Microprocessors)

• This is the generation where we are working today. The computers which we see around us belong to the fourth generation computers.
• By putting millions of transistors onto one single chip more calculation and faster speeds could be reaches by computers.
• Ted Hoff, employed by Intel invented a chip.
• The size of a pencil eraser that could so all the computing and logic of a computer.
•  It is evident that he next generation of computer i.e. fifth generation will be developed soon.
• In that generation, computer will possess artificial intelligence and it would be able to take self-decisions like a human beings.

Key Features

• Very large scale integration billions of circuits per cubic foot.
• Portable computer developed.

Things to remember: Supercomputers can execute a single program faster than a mainframe.

Examples– IBM system 3090, HP 9,000 etc…

                                 

Analog computer

  An analog computer is a computer that represents data by measurable quantities, as voltages than by expressing the data as numbers.

Example- Thermometer, speedometer, petrol pump indicator, multimeter etc.

 

Digital computer

 A digital computer is the most commonly used type of computer and is used to process information with quantities using digits, usually using the binary number system.

Hybrid (analog + digital) computer

 A combination of computers those are capable of inputting and outputting in both digital and analog signals. A hybrid computer system setup offers a cost effective method of performing complex simulations.

On the basis of size

Supercomputer

A supercomputer is a computer that performs at or near the currently highest operational rate for computers.

It is mainly used for scientific and engineering applications that must handle very large databases or do a great amount of computation.

For example, weather forecasting requires a supercomputer.

Mainframe computer

It is very large and expensive computer capable of supporting 100 or even 1,000 of users at a time.

Mini computer

A computer with processing and storage capabilities smaller than those of mainframe but larger than those microcomputer.

On the basis of Brand

IBM computers

It refers to a family of personal computers by IBM.

Apple/Macintosh computer

It is also known a Mac, is a line of personal computers (PC’s) designed, developed, and marketed by Apple Inc.

Let Us Summaries

• Charles Babbage is called the ‘Father of computer’.
• The first generation computer were huge, slow, expensive and often undependable.
• One transistor replaced the equivalent of 40 vacuum tube.
• Integrated circuit were used as the electronic component for computer.
• The microprocessor led toward the invention of personal computer or microcomputers.
• Digital computer processes information with quantities using digit usually using the binary number system.
• Hybrid computer is a combination of computer those are capable of inputting and outputting in both digital and analog signals.
• Supercomputer perform at or near the currently highest operational rate for computers.
• A minicomputer is a multiprocessing system capable of supporting from 4 to about 200 users simultaneously.
• Desktop Computer is personal or micro-mini computer sufficient to fit on a desk.
• Laptop is a portable computer complete with an integrated screen and keyboard.
• Palmtops have no keyboard but the screen serves both as an input and output device.