Generation and Classification of Computer for IBPS RRB Officers Selection Exam

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Development of computer


  • Abacus is known to be the first mechanical calculating device.
  • It was used to be performed addition and subtraction easily and speedily.
  • This device was a first developed by the Egyptians in the 10th century B. C, but it was given it final shape in the 12th century A. D. by the Chinese educationists.


  • As the necessity demanded, scientist started inventing better calculating device.
  • In this process, John Napier՚s of Scotland invented a calculating device, in the year 1617 called the Napier Bones.
  • In the device, Napier has used the bone rods, these rods that one can do addition, subtraction, multiplication, and division easily.
Napier Bones

Pascal Calculator

In the year 1642, Blaise Pascal a French scientist invented an adding machine called Pascal՚s calculator, which represents the help position of digit with the help of gears in it.

Pascal Calculator

Leibniz Calculator

In the year 1671, a German mathematics, Gottfried Leibniz modified the Pascal calculator and he developed a machine which could perform various calculation based on multiplication and division as well.

Leibiniz Calculator

Analytical Engine

  • In the year 1833, a scientist from England knows to be Charles Babbage invented such a machine.
  • This device was called Analytical engine and it deemed the first mechanical computer.
  • For this great invention of the computer, Sir Charles Babbage is also known as the father of the computer.
Analytical Engine
Generations of Computers
Comparison of Computer Generations
GenerationHardware FeatureCharacteristicsSystem names

(1942 - 1959)

Vacuum Tubes

Punch Cards

Support machine language only.

Very costly

Generate lot of heat

Consumed lot of electricity

  • TBM 701

(1959 - 1965)


Magnetic Tapes

Batch operating system

Faster, smaller and reliable than previous generation


  • Honeywell 400
  • CDC 1604
  • IBM 7030

(1965 - 1975)


Large capacity disk and Magnetic Tapes

Time Sharing OS

Faster, smaller and reliable cheaper

Easier to update

  • IBM 360/370
  • CDC 600
  • PDP 8/11

(1975 - 1988)

ICs with VLSI Technology

Semiconductor Memory

Magnetic tapes and floppy as portable

Multiprocessing & GUI OS

Object oriented programs

Small, affordable, easy to Use

Easier to update

  • Apple II
  • VAX 9000
  • CRAY 1/2


ICs with ULSI Technology

Large capacity hard disk with RAID Support

Optical disks as portable read-only storage media

Powerful servers, internet, Cluster computing

Powerful, cheaper, reliable, easy to use, portable

Rapid software development possible

  • IBM
  • Pentium

Classification of Computer

Classification on working system

  • Historically computers were classified according to processor types because development in processor and processing speeds were the developmental benchmarks.
  • All modern computers and computing devices use microprocessors whose speeds and storage capacities are skyrocketing day by day.
Types of Computers