History of computer

History of computer 

Introduction
For centuries man lived on earth without keeping records .He had no need for numbers and did no know to count .As he started to settle down in tribes , records and numbers became necessary .Sticks and pebbles ware used to count people  and animals .Later counting was done fingers and the fact that man has ten fingers led to the development of the decimal number  system .As nations grew trade commerce and  technology developed and the need to calculating aids were keenly felt .

MECHANICAL CALCULATING ERA
Abacus
The earlier calculating device ,which is still in use today ,is the abacus .It was first used in china ,some  3000 years ago .It consists of a computer wooden  frame with parallel bars  with heads strung on them .Moving the beads along the bars does counting .There are various version of the Abacus .Experienced users can calculate vary fast using  the Abacus and even beat the electronic calculator in simple  calculations .

Fig. of Abacus

Napier's Bone
In 15614 AD a Scottish mathematician by name John Napier made a set of rods to do simple multiplications .Numbers were carved on these rods called ‘bones ‘ as shown in the picture .the numbers were raved in such a way that  by simply placing them  side by side products of large numbers could be easily be obtained .
Napier however is better remembered for his invention of logarthms

Fig. of John Napier

Fig. of Napier's Bone

Slide rule 
Napier’s  invention of logarithm was soon followed by the invention of the slide rule in 1620 AD .An English mathematician William Oughtred  combined the principles of the  logarithm and Napier‘s bones to construct the slide  rule .It consist of two scales one moving over the other .

Engineers and mathematicians extensively used slide rules until the electronic calculations replaces them .

Fig, of William Oughtred

Fig. of Slide Rule

pascal's Calculation ( pascaline)
Around the year 1642 Ad  the great french mathematician BLAISE PASCAL   invented a simple mechanical calculator .It consisted of gears and wheels and registered numbers by rotating the wheels by one to ten steps .When a wheel moved by ten units ,the next higher digit wheel moved by one unit .this machine  could add and subtract very easily but  failed to multiply or divide .However ,pascal’s machine is recognized  as the first mechanical calculating device .

Fig. of Blaise Pascal

Fig. of Pascaline

Leibniz Calculation Machine
Pascaline was later developed  and modified in 1671 Ad by Gottfried von Leibnitz ,a German mathematician . Keibnitz’s  machine could perform multiplications and division too .the machine of pascal and  Leibnitz simple ,showed that machines  could perform arithmetic .

Fig of Gottfried von leibnitz

Fig. of Leibnitz's machine

Jacquard's Punched cards
While attempts were being made to improve the calculating machines , James  jacquard made a new  invention in the weaving industry .He  introduced a cardboard card with  holes  punched on it to guide the threads to produce different patterns .Thus ,jacquard managed to translate the instructions for patterns into cards containing punched holes ,this idea was later picked up by  mathematician to code instructions to computer in the form of punched cards  to do arithmetic operations .

Fig. of James Jacquard

Fig. of James Punchardcard

CHARLES BABBAGE 
Pascal  and Leibnitz’s machines were used for may years without any significant change in their basic design .the greatest drawback of these machines was that each operations was done manually step by step .Around 1822 AD , an English mathematician ,Charles Babbage ,successfully developed a machine called  the Difference engine ,which could solve algebraic equations  quite accurate .However ,it suffered from the basic deficiency o the earlier machines .

Fig. of Charles Babbage

Babbage drew  up designs  for his second machine called the Analytical machine. In this he was inspired jacquard’s  method of using punched cards for storing instructions .he  wanted to put the entire set of  instructions in to  a storage area  and  allow the machine to take up one instructions after the other automatically .thus his machine would have incorporated an input unit , a storage area , an output unit and a sequential  program control .In short  Babbage had designed a  machine that was a prototype  of the modern computer .but his ideas were far ahead of his time and the technology  of his time could not match them .so ,could not complete his machine .yet his theoretical machine contained all the elements of a modern computer  and Babbage  is often called the Father of  Modern Computer .

Lady ADA Lovelace 
Assisting in babbage ‘s work was LADY ADA  LOVELACE ,a brilliant mathematician and daughter of lord Byron .She helped him to draw  up plans for his machines as well as wrote programs .One  programming language  ADA is named in her  honor .

Fig. of Lady ADA

Tabulation Machine
The next big towards  the development of computers came from the USA .Dr. herman Hollerith adopted jacquard’s method of  storing information on cards to processes the 1880-90 censuses in the USA .the census information was codified and punched on cards ,which was later easily, read by machines.These machines could easily recognize the pattern of holes on the cards and sort them on the basis of sex ,age  and  other information punched on it .His “census machine” was more accurate and much faster than manual labor .The census procedure was complete in a very short time.Dr .hollerith was thus the first person to successfully   process a large volume of  data with the help of machines .Later he founded his own accounting machines company ,which finally merged with IBM .

DR. Herman Hollerith

Fig. of Tabulating Machine

ELECTRO-MECHANICAL ERA

MARK-1
Since the death of  Babbage  little progress was made in the development of  computers   until 1937 AD .In 1994 AD ,a  Harvard professor ,howard  Aioken ,completed the first calculating machine that could automatically sequence  of  arithmetic  operations.It was an electro -machinical  devised ,it used over 3000 electronically actuated switches : it was about 50 feet long and 8 feet high it could perform addition,subtraction ,multiplications and division and table reference on numbers as  large  as 23 decimal digits : it took about  0.3 second to add display at Harvard university .

Fig. of Mark-I

Atnasoff  Berry Computer ( ABC)
John  vincent atansoff and his assistant  Clifford berry invented ABC machine kin 1938 AD .It used vacuum tubes for internal logic and capacitors for storage .It was the first electronicx special purpose computer .

Fig. of ABC

John Von Neumann
About the same time the great m athematician john von Neumann wrote a papter in which he suggested the following two thing

• Binary number system should be used in computers .
• Computer instructions as well as data should be stored internally and executed automatically .

These two ideas have since become basic  parts of computer design .His second  suggestions in known as the stored program comcept  and  he is known as the Father of stored program.

Fig. of John Von Neumann

Electronic Computer Era

ENIAC ( Electronic Delay Storage Automatic Computer )
John mauchley and J.P  Eckert scientist of more school of engineering  university  of pennsyvania, USA built the first electron ic computer in 1946 .This machine was called  ENIAC (electreonic numerical integrator and calculator ) It could add two numbers in 200 microseconds and multiply them in 2000 microseconds .It was used to solve ballistic problems .

Fig. of ENIAC

EDSAC ( Electronic Delay Storage Automatic Computer )
The first computer to incorporate neumann's  idea was EDSAC built in 1949 by a group of scientists headed by maturic wilkes of Cambridge university  mathematical laboratory .It could add two multiply them in 4000 microseconds .

Fig. of EDSAC

EDVAC ( Electronic Discrete Variable Automatic Computer )
In  1952 john mushily ,j.p Eckert and john von Neumann invented EDVAC.It was the first computer based  on stored program comcept .It could store both instructions and data in binary form instead of decimal number or human readable words .

Fig. of  EDVAC

UNIVAC ( Universal Automatic Computer )
UNIVAC  was invented in 1951 by John Mauchly and J.P Eckert  .It used magnetic tape for input and output .It installed in 1954 at the office general electric company .It marked the arrival of commercially available digital computers for business and scientific purpose .

Fig. of UNIVAC