First Lecture

1. Introduction & History of
Computers,Their Applications
By: Khalid Khan
Sarhad University of Science & InformationTechnology
Peshawar

2. Contents
• What is Computer?
• Who is a User?
• Data & Information
• InformationTechnology (IT)
• History of Computers
• Generations
• Types of Computers
• Classification of Computers

3. What is Computer

4. What is Computer?
Definitions:
• A computer is normally considered as calculating machine
that can perform arithmetic operation at a very high speed.
• Computers are electronic devices that is programmed to
• accept data (input),
• (process) that data into useful information,
• produce (output), and then
• (store) for later use.

5. Who is a user?
• Someone that communicates with a computer

6. Data & Information
Definitions:
• DATA
 A collection of raw facts and figures is called data.
 It may consist of numbers, characters, symbols etc
• INFORMATION
 Processed data is called information.
 It is more meaningful than data.

7. InformationTechnology
• Information is data that is organized,
meaningful, and useful.
• Information technology is the use of systems
(especially computers and telecommunications)
for storing, retrieving, and sending information..
• Computer is a very important component of
information technology

8. History of Computers

9. Mechanical computers
(1600-1900)
early designs for
more traditional
computers -
based on
mechanical
techniques.
Slide rule
Abacus
Pascal
Calculator

10. Electronic computers
(1937-1953)

11. First Generation -VacuumTubes
1. From 1946 to 1956
•It can perform 2,000 to 16,000
additions per second
•Had main memory 100 bytes
to 2 kilobytes
2. Used vacuum tubes
3.Very large machines
•special rooms to house them
with air conditioning
•specially trained technicians to
run & maintain

12. Second Generation -Transistors
1. From 1959 to around 1965
2. Smaller, faster, and more reliable
 used transistors
 6,000 to 3,00,000 operations/s
 main memory 6 kilobytes to 1.3 megabytes
3. one-tenth the price of a 1st Generation
4. become common in larger businesses
and universities

13. Third Generation - Integrated Circuits
1. Form 1965 to around 1972
2. Used integrated circuits – many
transistors on one piece of silicon
3. Smaller, faster, more reliable, and lower
in price
• Size of a stove or refrigerator, some can fit
on desktops
• Can perform trillions of operations per
second
• Cost about one-tenth the amount of second
generation computers
4. These Computers become very common
in medium to large businesses

14. Fourth Generation - Microprocessors
1. From 1972 until now
2. Used large scale to very large scale integrated circuits
• Put more than one IC on a silicon chip
• Can do more than one function
3. smaller, faster, more reliable, and lower in price
• Size of a television or much smaller
• Can do 500,000 to 1,000,000,000 operations/second
• Cost one-tenth, or less, the amount of third generation
4. very common in homes and business

15. Types of Computer
• Analog computers
• Digital computers

16. Analog Computers
• An analog computer recognizes data as a
continuous measurement of a physical property.
• It has no state
• Its output is usually displayed on a meter or graphs.
• Examples are Analog clock, speedo-meter of a car,
thermo-meter etc

17. Digital Computers
• It works with numbers
• They breaks all types of information into tiny units and use
numbers to represent those pieces of information.
• Everything is described in two states i.e. either ON (1) or OFF
(0).
• They are very fast and have big memory

18. Classification of Computers

19. Basic Map
Micro
Computers
Mainframe
Computers
Super
Computers
Mini
Computers
Digital
Computers
Desktop
Computers
Laptop
Computers
Handheld
Computers
Workstations
Computers
Servers
Computers

20. Supercomputer
• A supercomputer is a computer with a high-level computational
capacity compared to a general-purpose computer.
• It comprised of multiple high performance computers working in
parallel as a single system.
• Super Computers uses thousands of processor at a same time.
• Used for nuclear weapon weather forecasting, Scientific
Simulition, oil and gas exploration or in large companies.

21. Mainframe
• Mainframes are huge computers
that could fill an entire room or
even a whole floor!
• mainframes can run multiple
instances of operating systems at
the same time.
• Mainframe are used primarily by
large organizations for critical
applications, bulk data processing
• It uses for online data storage.
• Mainframe used for transaction
processing in banking, Airlines etc

22. Workstation
• A desktop computer that has a more powerful
processor,
• additional memory (RAM, Hard drive) and
enhanced capabilities for performing a special
group of task, such as 3D Graphics or game
development.
• Multiple users can use single workstation all
together.

23. Server
• A computer that has been optimized to provide
services to other computers over a network.
• Servers usually have powerful processors, lots of
memory and large hard drives.
• Multiple CPU’s & Hard drives

24. DESKTOP
• A PC that is not designed for portability.
• you will set the computer up in a permanent location.
• Most desktops offer more power, storage and
versatility for less cost than portable computers.

25. Laptop
• Also called notebooks.
• Laptop are portable computers that integrate
the display, keyboard, a pointing device or
trackball, processor, memory and hard drive
all in a battery-operated package.

26. Palmtop
• More commonly known as Personal
Digital Assistants (PDAs)
• palmtops are tightly integrated
computers that often use flash memory
instead of a hard drive for storage.
• usually do not have keyboards but rely
on touchscreen technology for user
input.
• A slightly larger and heavier version of
the palmtop is the handheld
computer.