# History of Computer

Historical records will tell us that man has invented three types of devices to assist him in calculating and processing data. These devices could be classified into: a) Manual-mechanical

b) Electromechanical

c) Electronic

2000 BC - MECHANICAL COMPUTER

THE ABACUS

* Computations are done by sliding beads on a wire arranged on a tray. Came from the Greek word abax meaning flat surface John Napier(1617) – Logs and Bones

* a Scotsman, invented logarithms which use lookup tables to find the solution to otherwise tedious and error-prone mathematical calculations. Blaise Pascal 1642 – Arithmetic Engine

* Invented the first mechanical calculator.

The Arithmetic Engine or Pascaline

* used cogs and gears to solve math equations. Can add and subtract up to 8 digits. Gottfried Wilhelm von Leibnitz 1670 - Stepped Reckoner

* Invented a calculator which can multiply and divide directly as well as extract square roots. Joseph Marie Jacquard 1800 – Jacquard’s Loom

* First “programmable” machine.

* Used punched cards (binary instructions) to automate weaving loom. * Punched cards were a staple of early and modern computer programming. * Milestone in the development of textile industry and data processing Charles Babbage 1822

* the Father of Computers

Charles Babbage 1822 – Difference Engine by

* It is a calculator which can compile accurate navigational and artillery tables Charles Babbage 1835 –Analytical Engine

* The machine has two components: the memory and the mill. * The memory or storage that holds all calculations.

* The mill processes data fed to it.

Lady Augusta Ada – First Female Computer Programmer

* Countless of Lovelace

Electronic Computer Systems

First Generation:1943-1956

* Used vacuum tubes in electronic circuits.

* Used punch cards to input and externally store data.

* Up to 4K of memory.

* Programming in machine language and assembly language. * Required a compiler

* Vacuum Tubes controlled the flow of electricity in a computer. They got very hot and would burn out. When this happened, the computer stopped working. ELECTRO-MECHANICAL COMPUTERS

From Herman Hollerith’s 1890 Census Counting Machine to

Howard Aiken and the Harvard Mark I (1944)

Herman Hollerith 1884 – Punched Card Tabulating Machine

* Constructed an electromechanical machine used in the first computerized US census in 1890. * His machine was the first successful data processing machine. * He began a company called International Business Machines. Mark I or Automatic Sequence Controlled Calculator 1944

* It is considered as the largest electromechanical computer and the first automatic general-purpose digital computer. ELECTRONIC DIGITAL COMPUTERS

From John Vincent Atanasoff’s 1939 Atanasoff-Berry Computer (ABC) to the present day John Vincent Atanasoff and Clifford Berry 1939 “ABC COMPUTER “ * The ABC was the first electronic digital computer, invented by John Vincent Atanasoff * The ABC processed data in discrete, digital units (the digits 1 and 0). It also used the binary (base 2) number system in computation, the results being converted to and from decimal (base 10) for the purposes of human consumption. The ABC used vacuum tubes, punched cards and a memory device that looked like a drum. Colossus 1943

Turing

* made a major contribution to the development of a sophisticated computing machine called the Colossus which was used to help crack the codes of the German Enigma Machine. * Turing Machine is also known as the Universal Machine, the theoretical precursor to the electronic digital computer which Atanasoff was soon to invent. Rear Admiral Grace Murray Hopper 1945 First Computer Bug

ENIAC (Electronic Numerical Integrator and Computer) 1946 John Presper Eckert (1919-1995) and John Mauchly (1907-1980) * vacuum tubes, with the computing power of little more...

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