The document traces the evolution of computers from ancient manual calculating devices like the abacus and Napier's bones, to early electromechanical machines in the 17th-18th centuries developed by Pascal, Leibniz, and Babbage. It then discusses the development of programmable electromechanical computers in the mid-20th century like the Harvard Mark 1. The first electronic, digital computers that used vacuum tubes in the 1940s-1950s are also outlined, followed by the transition to transistors, integrated circuits, and microprocessors in subsequent generations from the 1950s to present.

1. Evolution of Computers
Done by
D.Sai Tarun
Kumar and
Barghav

2. Manual Calculating Devices
Abacus and Napier’s bones are examples
calculating devices.
Abacus
of manual
Abacus is used as the ancient counting board which is used in
Mesopotamia
around 3500 BC. The modern abacus probably
originated in 15 th century in China. Abacus is
used for calculation which is consistedof pitted
boards with pebbles or beads.
Napier’s bones
This calculating device was invented by
John Napier in 17 th century. Napier’s bones
are number rods that can be used for
multiplying a long number by a

3. mi-Automatic Calculating Devices
 Pascal’s adding machine (Pascaline) (1642):
One of the first semi-automatic mechanical devices,
the Pascaline , was developed by Blaise Pascal. This
brass
rectangular box had eight movable dials to add sums up
to eight digits long.
 Staffelwalze(the step reckoner)(1671):
German mathematician and philosopher Gottfried
Wilhelm von Libniz developed the Staffelwalze , which
was an improvement over the Pascaline. The
Staffelwalze allowed the user to add, subtract,
multiply, and divide.

4.  Jacquard’s loom(1801): Joseph Jacquard
devised a mechanical loom, called Jacquard’s loom,
which
made weaving complex patterns a lot easier. The device
used instuctions stored on a punched card to control the
movement of threads.
 Difference engine(1822): English mathematician
Charles Babbage, often called the
‘father of computer’, proposed a macine called
difference engine.
 Analytical engine(1832): Charles Babbage
proposed another machine, the Analytical
engine, which had the basic elements of a
modern general-purpose computer.

5. Electromechanical
Calculating Devices
The tabulating machine and Harvard Mark1 are examples
of Electromechanical Calculating Devices.
 Tabulating machine(1887): American inventor Herman
Hollerith invented the tabulating machine,
which used punched cards for for storing and
processing information. In 1890, Hollerith’s
machine wasused to process data for the US
census. In 1896,Hollerith founded the Tbulating
Machine Company, which, after a series of mergers,
eventually became International
Bussiness Machines(IBM)
in 1924.

6.  Harvard Mark1(1944): American Computer
engineer HowardH. Aiken devised the IBM
Automatic Sequence Controled Calculater or Harvard
Mark1. It was used for creating ballistic charts for the
US
Navy. Though slower in comparison to modern
computers(taking about 3 to 4 seconds per calculation), it
could perform basic arithmetic as well as
more complex calculations.
Electronic Computers
Electonic computers are classified into various
generations on the
basis of the difference in technology. Each of these
generations

7. First-generation Computers
First-generation computers used vaccum tubes. Some of
these are discussed below.
Atanasoff-Berry computer(1941): The Atanasoff Berry
Computer (ABC), built by John Atanasoff and Clifford Berry.
Z3(1941): The Z3, developed by German engineer Knrad Zuse, was
used in designing airplanes and missiles.
Colossus(1943): The colossus computers were made by the British to
decode German messages during World War2.
ENIAC(1939-1946): The Electronic Numerical Integrator and
Computer(ENIAC), developed by John Mauchly and
J.PresperEckert, was the 1 st
general –purpose digital computer. It was a huge machine,
weighing about 30 tons.
EDSAC(1947-1949: Electronic Delay Storage Automatic Calculator
EDSAC(1947-1949
(EDSAC) was designed by Professor M.Wilkes of

8. EDVAC(1949):Electronic Discrete Variable Automatic
EDVAC(1949):
Calculator (EdVAC), developed by John Mauchly and
J.Presper Eckert, was the successor of ENIAC. It could
hold
both a programand data in its memory.
UNIVAC1 (1951):Universal Automatic Computer1
(1951):
(UNIVAC)
was one of the first commercially available computers.
Second-Generation Computers(1954-1959)
Second-Generation Computers were based on
transistors.Model 604, IBM 1401, and IBM 1620
are a few examples of second-Generation computers.
Third-Generation Computers(1959-1971)
Third-Generation Computers were based on
integrated circuits. An integrated circuit

9. IBM’s 360 series and 370 series computers are
examples of Third-Generation Computers.
Forth-Generation Computers(1971-Present)
Forth-Generation Computers are based on
microprocessors.IBM’s
personal computer (PC) and Apple’s Macintosh are
examples of
Forth-Generation Computers.