A computer receives data as input, processes it according to instructions, and outputs the results. It has evolved over generations from mechanical calculators to modern devices powered by microprocessors and integrated circuits. A computer's basic functions include data input, processing, and output no matter the generation.

1. Generations
of
Computer

2. PROCESSING
DATA
OUTPUT
Definition
A computer is an electronic device that receives data as input, stores and
processes it, and gives the output according to the given instructions.

3. History of Computer
•Before the 1500s, in Europe, calculations were made
with an abacus, Invented around 500BC, available in
many cultures (China, Japan, Greece, Rome, etc.)
•In 1642, Blaise Pascal (French mathematician, physicist,
philosopher) invented a mechanical calculator called the
Pascaline
•In 1671, Gottfried von Leibniz (German mathematician,
philosopher) extended the Pascaline to do
multiplications, divisions, square roots: the Stepped
Reckoner
None of these machines had memory, and they required
human intervention at each step.

4. History of Computer
• In 1822 Charles Babbage (English mathematician,
philosopher), sometimes called the “father of
computing” built the Difference Engine
• Machine designed to automate the computation
(tabulation) of polynomial functions (which are known
to be good approximations of many useful functions)
– Based on the “method of finite difference”
– Implements some storage
• In 1833 Babbage designed the Analytical Engine, but he
died before he could build it
– It was built after his death, powered by steam

5. Generations of Computer
• Generation Zero: Mechanical Calculators
• First Generation: Vacuum Tube Computers (1946-57)
• Second Generation: Transistor Computers (1957-64)
• Third Generation: Integrated Circuits (1965-70)
• Fourth Generation: Microprocessors (1970-90)
• Fifth Generation: Artificial Intelligence (1990 - till date)

6. First Generation Computers
• The ENIAC computing system was
built by John Mauchly and J.
Presper Eckert at the Moore
School of Electrical Engineering of
the University of Pennsylvania.
• Example: ENIAC (Electronic
Numerical Integrator and
Calculator, UNIVAC(Universal
Automatic Computer)

7. First Generation Computers
• Basic component – Vacuum Tubes
• Processing Speed – Slow & Unreliable
Machine
• Size – Bulky & Non – Portable Machine
• Instructions – Only Machine Language
was used
• User Friendly – Very Difficult to
operate
• Cost – Production & Maintenance costs
were very High

8. Second Generation Computers
• Basic component – Transistors & Diodes
• Processing Speed – More reliable than 1st G
• Size – Reduced size but still Bulky
• Instructions – High-level Language was used
(Like COBOL, FORTRAN)
• User Friendly – Easy to operate from 1st G
• Example – IBM 7090, NCR 304

9. Third Generation Computers
• Basic component – Integrated Circuits
• Processing Speed – More reliable than 2nd G
• Size – Smaller than older generations
• Instructions –Expensive use of High-level
Language
• User Friendly – General-purpose Machine
used in commercial Application
• Example – IBM 360, CDC 7600

10. Fourth Generation Computers
• Basic component – Microprocessors (IC)
• Processing Speed – Most reliable than 3rd G
• Size – Smaller size making them portable
• Instructions – Very sophisticated programs &
Languages
• User Friendly –Easiest to operate
• Example – IBM 3090, VAX

11. Fifth Generation Computers
• Present and Beyond: Artificial
Intelligence, still in development.
• Size: Different portable sizes
• Example: Desktop, Laptop, Notebook,
Tablet, Smart Phone, Workstations