What is a computer?
• A computer is a general purpose device that can
be programmed to carry out a set of arithmetic
or logical operations.
• In 3000 BC early form of abacus with beads on
wires were used in China.
• This device allows users to make computations
using a system of sliding beads arranged on a rack.
• Joseph-Marie Jacquard developed a loom in which the
pattern being woven was controlled by punched cards.
• The punched cards contain digital information
represented by the presence or absence of holes in
• In 1833, Charles Babbage moved on from developing his
difference engine (for navigational calculations) to a
general purpose design
• Analytical Engine was a general-purpose programmable
computer, employing punch cards for input and a steam
engine for power, using the positions of gears and shafts to
• The marks the transition from mechanized arithmetic to
fully-fledged general purpose computation
The Difference Engine(1833) & Analytical
The Difference Engine(1833) & Analytical Engine (1837)
These marks the transition from mechanized arithmetic
to fully-fledged general purpose computation
Early electronic digital computers
• It was the first electronic general-purpose computer.
• It could add or subtract 5000 times a second, a thousand
times faster than any other machine.
ENIAC (Electronic Numerical Integrator and Computer)
• Unlike its predecessor the ENIAC, it was binary rather
than decimal, and was a stored program computer.
EDSAC (Electronic Delay Storage Automatic Calculator
Vacuum tubes replaced relays
Mid 1950's – transistors began to
Third generation: Integrated circuit (IC).First
microprocessor, the 4004, a chip with all the
circuitry for a calculator was made
Fourth generation and above: Very Large Scale
Integration (VLSI) and Networking
Developments in different generations
It is currently the world's fastest
total of 3,120,000 computing cores.
33.86 PFLOPS which is equalent to 3000
trillion calculations per second
• It will be used for simulation, analysis, and government
Present day super computer (Tianhe – 2)