EVOLUTION OF COMPUTERS

EVOLUTION OF COMPUTER :

Necessity is the mother of invention . the saying holds true for computer too. researchers invented computers because of man's search for fast and accurate calculating devices.

Blaise Pascal invented the first mechanical adding machines in 1642 . Later , in the year 1671 , Baron Gottfried Wilhelm von Leibniz of Germany invented the first calculator for multiplication . keyboard machines originated in the united states around 1880 and we use them even today . Around the same period , Herman Hollerith came up with the concept  of punched cards that computers used extensively as input medium even in late 1970s. Business machines and calculator made their appearance in Europe and And America towards the end of the nineteenth century.

Charles Babbage , a nineteenth century professor at Cambridge University , is considered the father of modern digital programmable  computers . He had employed a group of clerks for preparing mathematical  and statistical tables. Babbage had to spend several hours checking these tables because even utmost care and precautions could not eliminate human error , soon he became dissatisfied and exasperated with this type of monotonous job. As a result , the started thinking about building a machines that could compute tables guaranteed to be error- free . in 1842, Babbage came out with his new idea of a completely automatic Analytical Engine for performing basic arithmetic functions for any mathematical problem at an average speed of 60 additions per minute . Unfortunately , he was unable to product a working model of this machines because the precision required  to manufacture the machines was not available during that period . However , his efforts established a number of principles that are fundamental to the design of any digital programmable computer.

A major drawback of the early automatic calculating machines was that their programs were wired on boards that made it difficult to change programs. In 1940s, Dr. John Von Neumann introduced the "stored program" concept that helped in overcoming hard- wired program problem.  The basic idea  behind  this concept is that a sequences of instructions and data can be stored in memory of a computer for automatically directing flow of operations . this feature considerable influenced of development of modern digital computers because of ease with which different programs can be loaded and executed  on a single computer . Due to this feature , we often refer to modern digital computers as stored program digital computers.