The document provides an introduction to computers and their basic components. It defines a computer as an electronic device that can store, process, and retrieve data. Computers have various components including an input unit, processing unit, and output unit. The processing unit contains the arithmetic logic unit, control unit, and memory unit. The document discusses different types of computers and their characteristics, generations of computers, and applications of computers in various fields such as business, banking, education, and more.

1. Question :
What Has Many Keys But
Can’t even Open a single
door?

2. Answer :
The Computer

3. UNIT 1:
Introduction to Computer and
Operating System

4. What do you think when you
hear the word “computer”?

5. • Computers come in many shapes and sizes,
and they perform many different functions
in our daily lives.
• When you withdraw cash from an ATM,
scan groceries at the store, or use a
calculator, you're using a type of computer.

6. What is Computer?
• A computer is an electronic device that manipulates
information, or data. It has the ability to store,
retrieve, and process data.

7. The two principal characteristics of a
computer :
• It responds to a specific set of instructions in
a well-defined manner
• It can execute a prerecorded list of
instructions (a program).

8. Classification of Computers:
• Personal Computer (PC)
• Workstation
• Minicomputer
• Mainframe
• Supercomputer

10. Personal Computer (PC)

11. Workstation

12. Minicomputer

13. Mainframe Computer

14. Supercomputer

15. Characteristics of Computer:
• Speed
• Accuracy
• Reliability
• Memory
• Power of Remembering
• Versatility
• Integrity
• No Feelings

16. Block diagram of Computer

17. Basic Organisation of Computer System

18. Computer Components:
• Input Unit
• Process Unit: 1. ALU (Arithmetic Logical Unit)
2. CU (Control Unit)
3. MU (Memory Unit)
• Output Unit

19. 1.Input Unit:
• Input unit is used for entering data into computer
• It makes link between user and computer
• It translates information
• E.g.: Keyboard,Mouse,Joystick,Light
Pen,Trackball,Scanner,Graphic tablet etc

20. 2.Process Unit:
• Arithmetic and Logical operations
• CPU is the Heart of Computer System
• CPU itself has three components
a.ALU (Arithmetic Logic Unit)
b.MU (Memory Unit)
c.CU (Control Unit)

21. 3.Output Unit:
• We get information from Computer
• It is a link between Computer and users
• It translates information
• E.g. :Monitor, Printer etc

22. Computer Generations
1.First Generation(1942-1955)
2.Second Generation (1955-1964)
3.Third Generation (1964-1975)
4.Fourth Generation (1975-1989)
5.Fifth Generation (1989 onwards)

23. 1.First Generation(1942-1955)

24. 2. Second Generation (1955-1964)

25. 3. Third Generation (1964-1975)

26. 4. Fourth Generation (1975-1989)

27. 5. Fifth Generation (1989 onwards)

28. Advantages of Computer:
• High Speed
• Accuracy
• Storage Capability
• Diligence
• Automation
• Reduction in Paper work
• Reduction in cost
• Reliability
• Versatility

29. Disadvantages of Computer:
• No intelligence
• Environment
• No feelings
• Dependency

30. Applications:
1.Business 6. Insurance
2.Banking 7. Health care
3.Engineering Design 8.Communication
4.Education 9. Marketing
5.Military 10. Government

31. Computer System Hardware

33. Relationship between Hardware and Software

34. Computer Memory
• A memory is just like a human brain. It is used to store data and
instructions.
• Computer memory is the storage space in the computer, where
data is to be processed and instructions required for processing
are stored.
• The memory is divided into large number of small parts called
cells.
• Each location or cell has a unique address, which varies from
zero to memory size minus one.
• For example, if the computer has 64k words, then this memory
unit has 64 * 1024 = 65536 memory locations. The address of
these locations varies from 0 to 65535.

36. Memory is primarily of three types −
1.Cache Memory
2.Primary Memory/Main Memory
3.Secondary Memory