Page 11 - DCAP101_BASIC_COMPUTER_SKILLS

Basic Computer Skills

Notes 1.2 Evolution of Computers

Necessity is the mother of invention. The saying holds true for computers too. Computers
were invented because of man’s search for fast and accurate calculating devices.
Basic Pascal invented the first mechanical adding machine in 1642. Later, in the year 1671,
Baron Gottfried Wilhelm von Leibniz of Germany invented the first calculator for
multiplication. Keyboard machines originated States around 1880 and we use them even
today. Around the same period, Herman Hollerith came up with concept of punched
cards that were extensively used as input medium in computers even in late 1970s.
Machines and calculators made their appearance in Europe and America towards the end
of the century.

Charles Babbage, a nineteenth century Professor at Cambridge University, is considered the
father of modern digital 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 errors. Soon he became
dissatisfied and exasperated with this type of monotonous job. As a result, he started
thinking about building a machine that could compute tables guaranteed to be error-free.
In this process, Babbage designed a “Difference Engine” in the year 1822 that could produce
reliable tables. 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 produce
a working model of this machine because the precision engineering required to manufacture
the machine was not available during that period. However, his efforts established a number
of principles that are fundamental to the design of any digital computer. In order to have
a better idea of the evolution of computers it is worthwhile to discuss of the well-known
early computers. These are as follows:

1. The Mark I Computer (1937-44). Also known as Automatic Sequence Controlled
calculator, this was the first fully automatic calculating machine designed by Howard
A. Aiken of Harvard University in collaboration with IBM (International Business
Machines) Corporation. It was an electro-mechanical device (used both electronic and
mechanical components) based on the techniques already developed for punched card
machines.
Although this machine proved to be extremely reliable, it was very complex in design
and huge in size. It used over 3000 electrically actuated switches to control its operations
and was approximately feet long and 8 feet high. It was capable of performing five
basic arithmetic operations: addition, subtraction, multiplication, division, and table
reference on numbers as big as 23 decimal digits. It took approximately 0.3 second to
add two numbers and 4.5 seconds for multiplication of two numbers. Obviously, the
machine was very slow as compared to today’s computers.

2. The Atanasoff-Berry Computer (1939-42). Dr. John Atanasoff developed an electronic
machine to solve certain mathematical equations. The machine was called the Atanasoff-
Berry Computer, or ABC, after its inventor’s name and his assistant, Clifford Berry.
It used 45 vacuum tubes for internal logic and capacitors for storage.
3. The ENIAC (1943-46). The Electronic Numerical Integrator And Calculator (ENIAC)
was the first all electronic computer. It was constructed at the Moore School of
Engineering of the University of Pennsylvania, U.S.A. by a design team led by Professors
J. Presper Eckert and John Mauchly.
The team developed ENIAC because of military needs. It was used for many years to
solve ballistic related problems. It took up wall space in a 20 x 40 square feet room

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