A computer is an electronic device that can accept data as input, manipulate the data according to programmed instructions, produce output, and store results for future use. Computers are used in nearly all aspects of modern life including business, education, healthcare, science, engineering, manufacturing, government, and more. A computer consists of an input unit, output unit, central processing unit, and memory. The central processing unit contains an arithmetic logic unit and control unit that work together to process instructions and manipulate data stored in memory.

2. Computer
A computer is an electronic
device, operating under the
control of instructions stored
in its own memory, that can
accept data, manipulate the
data according to specified
rules, produce results, and
store the result for future use.

3. Information Technology is a general term that
describe any technology that helps to produce,
manipulate, store, disseminate information.
basically it is the combination of computer
&communication devices.

4. Importance & Uses of
Computer
Business
Education
Medicine & Health Care
Science
Engineering
Manufacturing
Government

5. Importance & Uses of
Computer
Defence
Music
Theatre, Film & Television
Home
Internet
Legal Practices

6. Why Is Computer Literacy
Necessary?
In most places of business a computer is a standard!
For example:
Auto Repair Shops
Computers are used for diagnostic repairs
Inventory of parts and supplies
Customer billing
Food service industry
Cosmetology
Banking sector

7. Characteristics of Computer
Speed
Storage
Accuracy
Versatility
Automation
Diligence
Reliability

8. According to function
According to function computers can be classified
into four types. These classification of computer
based on principle of operation and hardware
structure.
 Digital Computer
 Analog Computer
 Hybrid Computer

9. Digital Computer
A Digital computer works with data in term of discrete
number or digit. These number are used to perform,
arithmetic calculations and also make logical decision to
reach a conclusion depending on the data they receive
from the user. All the expressions are coded into binary
digits (0 and 1) inside the computer and it manipulates
them at very fast speed.

10. Analog Computer
Analog computers actually is a measuring device. An
analog computer measures continues type of data and
use a physical quantity, such as electric current,
speed, weight etc. Analog Computers are the first
Computers being developed & provide the base for the
development of modern digital computers. These
computers are mainly made of electrical devices like
resisters, amplifiers & transistors.

11. Hybrid Computer
A Hybrid computer is, which combines the analog &
digital capabilities in the same computer system.
Hybrid computers help the user to exploit the
machine's ability to process both continuous and
discrete data. These machines are generally used for
scientific applications & it is also used as a
controlling device in an industrial process.

12. Components of Computer
There are four basic components of computer:
Input unit
Output unit
Central Processing Unit
Memory

13. Block Diagram of Computer
Input unit
Central
Processing
unit
Output unit
Memory

14. 1: Input Devices
Key Board
Mouse
Voice Data Entry
Joy Stick
Light Pen
Scanner
Secondary Storage Devices (floppy, Magnetic Tape
etc).

15. 2:Output Devices
Monitor
Printer
Speaker
Storage Devices

16. 3: Central Processing Unit
The Central Processing Unit has three main parts
Arithmetic Logic Unit
Control Unit
Main Memory
ALU
CU
Main Memory

17. Functions of CPU
Arithmetic Operations
(+,-,*,/,%)
Logical Decision
(<,>, =)
Data transmission
Manipulating Tasks
Display Results/ Store in memory.

18. Functioning of Arithmetic Logic Unit
Register
A register is combination of memory storage locations
called Flip-Flops. It stores one bit.
Accumulator
A register called “Accumulator” when it works for
ALU.

19. Functioning of Arithmetic Logic Unit
Accumulator consist of two parts
Memory Data Register
It holds all data & instructions temporarily & then pass
to the main memory.
Memory Address Register
MAR contains the address of the memory location
whose data is to be transferred into MDR.

20. Control Unit
CU also called the NERVE CENTRE of the computer.
CU has an Electronic Clock.
Electronic Pulses
(equal interval of time )
Speed in MHZ (10^6HZ).

21. Functioning of Control Unit
Instruction Cycle Consist of two parts
Fetch Cycle
The CU fetches the instruction from MDR & places it
in the current Instruction register.
Execution Cycle
The CU then decodes the instruction & send data for
concerned device for the execution.

22.  Random Access Memory (RAM)
 Read Only Memory (ROM)
 Complementary metal oxide semiconductor
chip (CMOS)
 Flash Memory
 Cache Memory
 Virtual Memory

23. Random Access Memory (RAM)
read/ write
Volatile in nature
hold software instructions
Read Only Memory (ROM)
Non Volatile / Permanent in nature
Less costly
Hold BIOS instructions

24. Types of RAM
Dynamic RAM
Cheaper
Transistor
Refresh periodically
(in 2 ms)
Access Time
(150ns-----200ns)
Static RAM
Expensive
More Power
More space
Access Time fast
(80ns-------90ns)

25. •SDRAM
It is synchronized by the system clock and much faster
then static RAM
•DDR.RAM
Double Data Rate Synchronized dynamic RAM
Its speed is very high measured in mega hertz used in
Apple computers.
•SIMM: Single in line memory chip
•DIMM: Dual in line memory chip

26. Types of ROM
1. Programmable Read Only Memory:
Information once store in PROM store permanent &
can not be changed or erased.
Entering the information is known as Burning the
PROM.
2. Mask Read Only Memory:
Information is permanently recorded by the masking
& metallization process.

27. Types of ROM
3. Erasable Programmable Read Only Memory:
EPROM is cheap, reliable & widely available.
The data will be erase when chip under the high
intensity ultraviolet light for 30 minutes. But we
lost whole data.
4. Electronically Erasable Programmable Read
Only Memory:
Using the electrical signals the data will be erase
in chunks in milliseconds.

28. Complementary metal oxide semiconductor chip
It is powered by battery .that’s why it don’t lose the
data as lights goes off. It has some flexible start up
instruction for example time ,date .
Flash Memory
It can erased data more than once and reprogrammed.
it available up to 8 gigabytes. it is used not only in
computers but also in digital camera, pagers, cell
phones etc

29. Cache Memory & its Types
It temporarily stores instructions and data that the
processor is likely to use frequently. So it is used to
speed up the system.
Level 1: part of microprocessor chip, also called
internal cache. it operates much faster than level 2.it
stores 256 kilobytes data.
Level 2:it is also called external cache. It is available
up
to 2 or more giga bytes
• Level 3: it is also separate from the motherboard .It is
found only on very high end computers.

30. Virtual Memory
It is some free hard-disk space that is used to extend
the capacity of RAM.
The processor searching for data in the following
order.
 L1
L2
RAM
 CD
Hard Disk

31. Process States
Interleaving: It is process in which the CPU alternates
communication b/w two or more memory banks .it is
used usually in large setup for server or workstation.
Bursting :It is used to provide the additional data to
CPU on the basis of statistical method that address
what data will be used next.
Pipelining :It is used to divide a task in to small
stages . So CPU works in stages & than switch to next
according to electronic clock.
Hyperthreding :Superscalar architerture means
computer has the ability to solve two transaction @ per
clock cycle.type of this technology is Hyperthreding

32. Secondary Storage Devices
Magnetic Tape
Floppy Disk
Hard Disk
CD’s & DVD’s
USB