History of Computers

MANUAL COMPUTING DEVICES:
Abacus-considered as the earliest device for calculation.


Napiers Bone-named after its inventor,this is a single tool made up of multiplication tables inscribed in a wood or bone.


Slide Rule-single straight two-foot long ruler plotted with a logarithmic scale.


Pascaline-the machine was the first operational calculating machine that could add large numbers.


Step Reckoner-improved the pascaline into a device that could add,subtract,multiply,divide and get square roots.


Difference engine-automatically calculated mathematical tables.


analytical engine- invented by charles babbage.


electromechanical computer:
holleriths tabulating machine- this machine was capable of representing,reading and assembling data.


Electronic computers:
mark1-first operating machine that could perform computations automatically.


ENIAC- first general purpose electronic computer which was made up of vacuum tubes.


UNIVAC-first commercially available computer that could perform about 1905 operations per second running on a 2.25 megahertz clock.