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  • Mousam Pradhan

Chapter - 2 : History of Computer

Subject: Computer Fundamentals | ▒

The need for a tool, that could be used for counting, leads to the development or invention of the computer. The origin and developmental history of computer can be studied in 4 ways:

I. The progression of computer on the basis of accessibility.

II. The progression in hardware representation of a bit of data.

III. The progression of calculating devices.

IV. Generations of Computer.

I. The progression of computer on the basis of accessibility:

1. In 1950s: Almost impossible to use except by very patient geniuses.

2. In 1960s and 1970s: Programmable by highly trained experts only.

3. In 1980s and onward: Useable by just about anyone.

II. The progression in hardware representation of a bit of data:

1. Vacuum tubes (in 1950s): one bit on the size of a thumb.

2. Transistors (in 1950s and 1960s): one bit on the size of a fingernail.

3. Integrated Circuit (IC) (in 1960s and 1970s): Thousands of bits on the size of a hand.

4. Silicon computer chips (in 1970s and on): Millions of bits on the size of a fingernail.

III. The progression of calculating devices.


Inventor: by the Chinese and later by the Japanese (named it as "SORABAN").

Year of Invention: 3500 B.C.

Structural Design: It consists of rows of beads that slide on sticks (which are mounted on a rectangular frame). The Frame is divided into two sections so that each row of beads has one sector with one or two beads and another sector with four or five beads.

Function: Addition and subtraction.

2. Adding Machine

Also known as Pascal's Calculator

Inventor: Blaise Pascal (1623-1662)

Year of Invention: 1642

Structural Design: Adding a machine is a gear-driven machine. It is of the size of a shoe-box, consisting of rows of teethed wheels with dials numbered 0 to 9. the first wheel represents units, the second tens and so on.

How it works?: The calculation can be done or performed by rotating the gears in the forward or backward direction.

Function: Addition and Subtraction

3. Analytical Engine

Inventor: Charles Babbage

Year of Invention: 1833

Structural Design: Babbage's analytical engine is comparable to any modern computer.

How it works? : This machine can perform arithmetic operations for any mathematical problem on data read in the form of a punched card and a flexible output in the form of a punched card on a printed page.

Function: Any arithmetic operations.

NOTE: Charles Babbage's efforts were commendable and earned him the title of "Father of Modern Computer".


Full form: Electronic Numerical Integrator And Calculator

Inventor: John W. Mauchly and J. P. Eckert of Pennsylvania University

Year of Invention: 1946

Structure/Design: It was the first electronic general-purpose computer. It was turning-complete and digital.

Function: It could solve a large category of numerical problems through reprogramming.


(a) It consisted of 18,000 vacuum tubes and 1,500 relays.

(b) It has a weight of 30 tonnes.

(c) It consumed 140 kilowatts of power.

(d) 6000 multi-position switches.

(e) It occupied 1,500 square feet of floor space.

(f) It costs US$5,00,000

(g) It had 20 registers.

Applications/Used for:

(a) To study the feasibility of the thermonuclear weapon.

(b) To calculate artillery firing tables for the United States' Army's Ballistic Research Laboratory.


Full form: Electronic Delayed Storage Automatic Computer

Inventor: Mourice Wilkes at laboratories of Cambridge University, England

Year of Invention: 1949

Structure/Design: EDSAC used mercury delay lines for memory, and derated vacuum tubes for logic. The input was via a five-hole punched tapes and output via a teleprinter.

Functions: Addition, Subtraction, Multiply-And-Add, Shift left, AND-and-Add, Arithmetical shift right.


Full form: Electronic Discrete Variable Automatic Computer

Inventor: John W. Mauchly and J.P.Eckert

Year of Invention: 1950

Function: Addition, Subtraction, Multiplication, Programmed division and automatic checking with an ultrasonic serial memory capacity of 1,000 44-bit words.

Structure/Design: Physically, EDVAC comprised of the following components:

(a) A magnetic tape reader-recorder.

(b) A control unit with an oscilloscope.

(c) A dispatcher unit to receive instructions from the control and memory and direct them to other units.

(d) A computation unit to perform arithmetic operations on a pair of numbers at a time and send the result to memory after checking on a duplicate unit.

(e) A timer

(f) A dual memory unit consisting of two sets of 64 memory acoustic delay lines of eight word capacity on each line.

(g) Three temporary tanks each holding a single word.


Full form: UNIversal Automatic Computer

Inventor: John W. Mauchly, J. P. Eckert, and Remington Rand

Year of Invention: 1951

Features: Speed, Reliability and Memory capacity

First Installation: at US Bureau of Census

Structure/Design: UNIVAC used 5,000 vacuum tubes, weighed 16,000 pounds(1.3 metric tonnes), consumed 1.25 kW, and could perform 1,905 operations per second running on a 2.25 MHz clock. The complete system occupied more than 35.5 sq. m (382 sq. ft.) of floor space. It was one of the first electronic computers to use magnetic tapes as an input-output medium.

IV. Generations of Computer

The history of computer development is often used to reference the different generations of computing devices. Each one of the five generations of computers is characterized by a major technological development that fundamentally changed the way computers operate.

1. First Generation

Period: 1940-56

Switching Device: Vacuum tubes (invented by Lee Deforest)

Example: ENIAC, UNIVAC-I, IBM-701, IBM-650, etc.


(a) Too big in size

(b) Slow in speed

(c) Low-level accuracy

(d) Unreliable

(e) Difficult to program and use

(f) Produce a large amount of heat

2. Second Generation

Period: 1956-65

Switching device: Transistor (invented by J. Bardeen, H. W. Brattain, and W. Shockley)

Examples: IBM-700, 1401, 1602, 7094, CDC-1604, 3600, Mark-III, etc.


1. Smaller in size

2. Faster in speed

3. High-level accuracy and reliability

(as compared to the first generation of computers)

3. Third Generation

Period: 1966-75

Switching device: Integrated Circuits (I.C.). It was invented by Robert Noyce and Jack Kilby.


1. IC was used instead of transistors in the third generation of computers.

2. The third generation of computers was smaller in size and cheaper as compared to the second generation of computers.

3. They were fast and more reliable.

4. The high-level language was developed.

5. Magnetic core and solid states as storage memory.

6. They were able to reduce computational time and low maintenance costs.

7. Input/output devices became more sophisticated.

Examples: PDP-8, PDP-11, ICL2900, IBM-360 and IBM-370.

4. Fourth Generation

Period: 1975 to Present

Switching Device: Large-Scale Integrated Circuit Microprocessor. The microprocessor is a silicon chip containing millions of microscopic transistors.

Example: IBM-4341, DEC 10, STAR 1000, PUP 11 and Apple II.


1. The fourth-generation computers have microprocessor-based systems.

2. They are the cheapest among all the computer generation.

3. The speed, accuracy, and reliability of the computers were improved in the fourth generation.

4. Many high-level languages were developed in the fourth generation such as COBOL, FORTRAN, BASIC, PASCAL and C language.

5. A further refinement of input/output devices was developed.

6. Networking between the systems was developed.

5. Fifth Generation

Switching device: Artificial Intelligence

Characteristics :

1. The fifth-generation computers will use super large scale integrator chips.

2. They will have artificial intelligence.

3. They will be able to recognize images and graphs.

4. The fifth generation of computers aims to be able to solve the highly complex problem including decision making, logical reasoning.

5. They will be able to use more than one CPU for faster processing speed.

6. The fifth generation of computers is intended to work with natural language.