This document provides a summary of the history and generations of computers. It discusses the major developments from the mechanical era through the electronic era. Some of the key inventions and advances discussed include the abacus, Napier's bones, the slide rule, Pascaline, Difference Engine, ENIAC, stored program concept, and integrated circuits. The document also summarizes the five generations of computers based on the underlying technology used, from vacuum tubes to transistors to microprocessors. Finally, it briefly introduces artificial intelligence and its role in future fifth generation computers.

1. Repair & Maintenance
D.Com II/II
Unit 4: History and Generation of Computer
Lecture by : Er. Ashish K.C (Khatri)

2. History of Computer:
▪ Mechanical Era
▪ Electro-Mechanical Era
▪ Electronics Era
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3. # Mechanical Era:
- only mechanical devices were used for the purpose of counting and computing
manually.
- machines were based on the moving parts, operated completely by machines and
they did not have any logical control in operation.
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4. Few inventions in mechanical
era:
1. ABACUS :
- developed by chinese before 3000 B.C
- consists of rectangular frame carrying
no. of rods and coils along with beads.
- two parts : heaven and earth
- heaven : upper part with 2 beads
- earth : lower parts with 5 beads
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5. 2. Napier’s Bone :
- developed by John Napier, Scottish Mathematician, in 1617 A.D
- Set of rods for purpose of multiplication.
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23 × 5 = 115

6. 3. Slide Rule :
- In 1620 A.D, developed by English Mathematician William Oughtred.
- two movable scales sliding upon one another.
- uses principles of logarithm.
- easy to find product, quotient or any other functions simply viewing on the scale.
- can calculate square, squareroots.
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7. 4. Pascaline
- 1642 A.D, developed by French mathematician Blaise Pascal.
- consists toothed wheels or gears having digits 0 to 9.
- can add and subtract 8- bit numbers.
- no direct multiplication or division.
- to help his father, tax superintendent.
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8. 5. Leibnitz Calculating Machine:
- In 1671 A.D, developed by German mathematician Gottfried Wilhelm Von Leibniz.
- In 1694, a modification was made using stepped dials, so called stepped reckoner.
- could perform addition, subtraction, multiplication and division.
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9. 6. Jacquard’s Loom:
- in 1801 A.D, developed by French Silk Weaver Joseph Marie Jacquard.
- used punched card for intricate design of patterns.
- function of loom was based on presence or absence of holes.
- this gave the concept of binary system.
- first programmable device.
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10. 7. Difference Engine:
- In 1822 A.D, invented by Charles Babbage.
- would be able to compute table of numbers, such as logarithm tables.
- funded by British government.
- could eliminate errors.
- became most expensive due to complexity in design and computing.
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11. 8. Analytical engine:
- In 1833 A.D,
- was very large and powered by 6 steam engines
- used punched cards to represent data
- patterns of punched holes were used to represent the raw data
- first machine to use binary system
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12. 9. Lady Augusta Ada Lovelace:
- First computer programmer
- student of Charles babbage
- operated and programmed Analytical Engine
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13. 10. Boolean Algebra:
- in 1854 A.D, Gorge Boole an English mathematician introduced concept of Boolean
algebra.
- is a method of reducing statements in logic to algebraic statements by using simple set of
statements.
- Boolean logic is the principle of arithmetic operations on modern digital computers.
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14. 11. Tabulating Machine:
- In 1887 A.D, developed by Dr. Herman Hollerith, an American census statiscian.
- automatically read census information that had been punched onto cards.
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15. # Electro-Mechanical Era:
- electricity was used to operate the computers but computers still had many
mechanical components.
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16. Few inventions in Electro-
mechanical era:
1. Mark-I :
- In 1937 A.D, developed by Howard Aiken of Harvard University
- also known as Automatic Sequence Controlled Calculator (ASCC)
- handled 23-decimal places and could perform all four arithmetic operations
- handle logarithms and trigonometric functions
- used 18000 vacuum tubes
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17. 2. Atnasoff Berry Computer (ABC):
- In 1939, developed by Dr. John Vincent Atanasoff (prof. of Mathematics and Physics)
and Clifford Berry.
- first electronic special purpose computer.
- used 19000 vaccum tubes.
- mainly designed for special purpose of solving systems of simultaneous equations.
- used by military to computer firing and blasting missiles.
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18. # Electronic Era
- is modern era of computer in which mechanical devices were replaced by fully
electronic circuits.
- calculations were based on digital mechanism,
- computers in this era also had the stored program concept.
- major significance is the classification of computers in generation based on electronic
component.
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19. Few Inventions of Electronic
era:
1. ENIAC:
- Electronic Numerical and Integrated Calculator.
- first general purpose computer
- built in 1946 by John Mauchly and J. Presper Eckert.
- capable of reprogrammed to solve a full range of computing problems.
- used around 17000 vacuum tubes, 7200 crystal diodes, 70000 resistors, 10000
capacitors and around 5 million hand soldered joints.
- took input from IBM card reader and IBM card punch as output.
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20. 2. John Von Neumann:
- contributed a new understanding of how practical fast computers, should be organized
and built.
- these ideas are often referred to as stored program technique.
- In 1945 he proposed:
a. stored program technique inside the computer
b. Binary number to be used in computer
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21. 3. EDSAC:
- Electronic Delay Storage automatic computer
- was early British computer developed by Maurice V. Wilkes and his team at Cambridge
University in 1949
- first computer used to store a program.
- used 3000 vacuum tubes to process data.
- programs were input using paper tape and output result were passed to tele-printer.
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22. 4. EDVAC :
- Electronic Discrete Variable Automatic Computer.
- First stored program computer in U.S.
- was completed in 1952 by J. Presper Eckert and John William Mauchly.
- was bult for U.S Army’s Ballistics research Laboratory
- used magnetic tape for storing data and instructions.
- used 600 vacuum tubes and 12000 diodes.
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23. 5. UNIVAC :
- Universal Automatic Computer
- first commercial computer produced in U.S developed by J. Presper Eckert and John
William Mauchly in 1951
- first general purpose electronic digital computer.
- used magnetic tape for data input and output.
- used 5200 vacuum tubes to process data.
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24. # History of Computer in Nepal
- in 2018 B.S, an electronic calculator called “ Facit ” was used to prepare census that
took more than 6 years.
- In 2028 B.S, IBM 1401( a second generation computer) was brought in rent to
compute census. It took 1year and 7 months.
- In 2031 B.S, National Computer Center ( NCC ) was established.
- In 2038 B.S ICL 2950/10 ( Fourth generation computer) was brought to compute
census data. It took 1 year and 3 months.
- After 2039 B.S, other computers were allowed to import.
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25. Generations of Computer:
- generation in computer terminology is a change in hardware and software that a
computer used.
- The development of computer that took place in five distinct phases is known as
generation of computer.
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26. # First generation:
- 1942 to 1955 A.D
- based on Vacuum tube technology.
- operating speed was upto millisecond.
- very expensive to operate and used large amount of electricity
- used magnetic drums for memory
- input was in the form of punched card and output in the form of printout
- used machine level language
- Examples: ENIAC, UNIVAC, EDSAC, etc
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27. Vacuum tube:
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28. 28

29. # Second Generation:
- 1956 to 1964
- used transistors as main component.
- transistor made it smaller, faster and cheaper than first generation
- required less power and emitted less heat
- used magnetic disk and magnetic tapes for storage
- used assembly language and high level language
- Example: IBM 1401, IBM 1620, UNIVAC-II, etc
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30. 30

31. # Third Generation:
- 1965 to 1972
- used Integrated Circuit as main component.
- more reliable, smaller, cheaper than previous generation
- used semiconductor device as memory.
- consumed less power and generated less heat
- used high level programming language
- Operating System were used
- Keyboard was used as input device and monitor as output
- Example: IBM-360, ICL-1900, VAX-750, etc
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32. 32

33. Classification of IC:
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Integrated Circuit No. of components
SSI ( Small Scale Integration) 1 to 20
MSI (Medium Scale Integration) 20 to 100
LSI (Large Scale Integration) 100 to 1000
VLSI (Very Large Scale Integration) 1000 to 10,000
ULSI (Ultra Large Scale Integration) more than 10,000

34. # Fourth Generation:
- 1973 to 1990
- based on microprocessor technology
- used VLSI for electronic circuits
- smallest and cheapest among all other generation
- are portable and more reliable
- consume less power and generate small amount of heat
- used Graphical User interface operating system
- Mouse were used
- Example: IBM-PC, Apple/Macintosh, etc
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35. # Fifth Generation:
- are future generation computers.
- will have parallel processing.
- will possess Artificial Intelligence.
- will implement knowledge based problems solving technique.
- will use bio-chips as main component.
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37. 37
Features 1st Generation 2nd Generation 3rd Generation 4th Generation 5th Generation
Time 1942-1955 1955-1963 1963-1971 1971-1990 1990-
Device used Vacuum tube Transistors Microprocessor/
IC
VLSI ULSI, Bio chips
Size Bigger than
room
Smaller than 1st Smaller than 2nd Smaller than 3rd Smaller than 4th
Cost High Cheaper than
1st
Cheaper than
2nd
Cheaper than
3rd
Computing time Milli second Micro second Nano second Pico second
Language used LLL LLL HLL HLL HLL
Power
consumption
High Lower Lower Lower Lower
Example UNIVAC-I IBM 1401 IBM 360 Pentium I, II,III Latest laptop,
ultra book, etc

38. # Artificial Intelligence:
- is the technique and software that enables computer to mimic human behavior.
- is a science of making machines that imitates human thinking and behavior.
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40. End of Unit
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