Basics of Internet and Computer Applicatios

                History And Generation of computer

        1.1   History of computer

                     (1) Early Calculating Devices

                     (2) middle Age Computer 

1.1)   History of Computer :-   

                    Man in the early days used to count whit his fingers and manipulate numbers 

manually. But technological development faster computing device. This led to the develo-

-pment of computers. The Abacus and the personal computer are two devices separated

by thousands of years of history . This can be depicted in the following parts:

(1) :-   Early calculating Devices 

The Abacus was used in 5000 BC for counting and computations . It consists of a frame  with some bars fixed across it. Each bar had some beads which could be moved along each bar. Every bead represented a position in the number system. in the following figure it can be seen how the number 45968 can be represented using Abacus. Each bead on the right hand side represents a fixed position. Each bar represents units, tens, hundreds.........

Napier's Bones

            Johnk Napier, a Scottish Mathematician invented a tool which helped him in doing the tedious calculations involved in Astronomy. For this he used 9 strips of bones called Napier's Bones and divided each into 10 squares. Again each square was divided into 2 parts. The lower half indicated units and the upper half indicated tens. He used the principle of multiples to fill the squares. whit the help of this chart he could do all sorts of multiplications.

Oughtred's slide Rule 

         Napier also developed the method of logarithm. IN the logarithm method, multiplication and division can be done by the adding and subtracting not the numbers themselves, but with the help of related number, known as logarithms. all engineering calculations are being done with the slide-rule which is a calculation device that uses the principle of logarithms.

Pascal's Calculator

      In 1642 the great French mathematician and philosopher Blase Pascal invented the first functional automatic calculator. This brass rectangular box, also colled  a pascaline as shown. The machine consisted of gears,wheels and dials.Each wheel had 10 segments like that of wheel completed a rotation, the next wheel moved by one segment. with this calculator, addition, and subtraction could be performed by dialing  these series of wheels bearing the numbers 0 to 9 around their circumference.   

(2) :-   Middle Age Computers 

            

                        mechanical computers was introduced in the decade of 1930s. The Z1, the binary number system based computer was developed by Konrad Zuse in 1938 in Germany. New again Z3 was developed in 1941 which employed relays as electromechanical binary switches to construct arithmetic unit.

In may 1944, prof . Haward Aiken of Havard University with the cooperation of IBM developed the first Electro-Mechanical Digital computer  called as Automatic sequence controlled calculator named Harvard mark-1.

    john V. Atansoff was the person of lowa starte University who developed the first special purpose electronic computer using valves in late 1930s,and  completed it in 1942. It contained an add - subtract unit and wos of  small size with 300 valves .Its memory unit consisted of capacitors mounted on a  rotating drum. If used - binary number for its operatino .Each capacitor was capable of storing one binary digit . It used number of input/output (I/O)devices including a card punch and a card reader.