Lesson Notes By Weeks and Term - Junior Secondary School 1









Historical development of computer can be categorized into three. These include:

  1. Mechanical device 
  2. Electro-mechanical device
  3. Electronic devices and modern computer



These are the devices that involve the use of physical forces to operate them. The following are examples of mechanical devices in order they were invented and used.

  1. Abacus: Abacus is known to be the first mechanical calculating device which was used to be performed arithmetic calculation such as addition and subtraction easily and speedily. This device was first develop by the Egyptians and improved upon by the Chinese educationists. Chinese were the first to use the abacus.
  2. Astrolabe: This mechanical calculating instrument also came into use about 2000years ago for finding direction and in astronomy. It consists of two flat circular discs, usually made of brass and ranges from about 7.5cm to 25cm in diameter.
  3. Slide rule: This mechanical device was used by engineers and scientists to simplify multiplication, division and finding root of numbers. The slide rule is an analog device and was invented by William Oughtred. It consists of a ruler designed with scales and a sliding central strip.
  4. Pascaline: This machine is a mechanical device that was developed by Blaise Pascal a French scientist. It invented   in the year 1642.It was called numerical wheel calculator to carry out computation.
  5. Reckoner or Leibnz Calculator: In the year 1671, a German mathematician, Gottfried Leibniz modified the Pascal calculator and he developed a machine which could perform various calculation based on multiplication and division as well. 





These are the machines were developed to make counting and calculations easier and faster. The following are examples of electro-mechanical devices.

  1. John Napier’s bones (1550-1617): John Napier’s of Scotland invented a calculating device, in the year 1617 called the Napier Bones or Napier rods: The rods were mainly multiplication tables written on sticks of wood or bone .The rods were also used in taking square roots and cube roots.
  2. Blasier Pascal’s machine (1623-1662): Blasier Pascal was a French mathematician who invented electron-mechanical device called Pascal’s machine that was used for calculation .It was first digital calculating machine in 1642.
  3. Gottfried Wilhelm von Leibniz’s machine (1646-1716): Gottfried Wilhelm was a German Philosopher and mathematician who was the discovery of fundamental principle of calculus and also invented a calculating machine capable of multiplying, dividing and calculating square roots.
  4. Joseph Marie Jacquard’s loom (1752-1834): Joseph Jacquard was a French silk weaver and inventor that invented Jacquard automatic loom mechanism using punched cards that controlled the weaving of the cloth and any design pattern could be obtained automatically.
  5. Charles Babbage’s machine(1792- 1871) : Charles Babbage’s was a British mathematician and inventor .He invented machine which is considered to be a modern computer today .He built machine called difference engine and analytical engine .He was regarded as the father of modern computer.
  6. Philip Emeagwali: Philip Emeagwali was born in Akure, Nigeria in April, 1967.He works as a computer scientist which contributed greatly to internet technology .He was regarded as a father of internet.




These are devices that form the modern computer .These are electronic devices that use electric current to power and operate. They include the following:

  1. Herman Hollerith punched card (1860-1929): Hollerith was an America statistician who developed a mechanical tabulator on punched card and also modern computer.
  2. John Von Neumann’s machine (1903-1957) : John von Neumann was a Hungarian born mathematician 


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