introduction to computer i prepare the best book .

1. Lecture:Barkhad mohamed
omar{suldaan}
Book:-Introduction to Computer.
Faculty: BA & public administration
Lecture hours:2hrs

2. Concept of Computers
Introduction.
Computer is electronic equipment, it is mainly used
for automating manual tasks.
Using computer you can perform tasks quickly,
effectively and in error free manner. Be it any
organization, office , factory or institution, you can
find people making use of computer there.
In offices, computers are used for preparing letters.
Documents and reports.
The first mechanical computer, created by Charles
Babbage in 1822, doesn't really resemble what most
would consider a computer today.

3. What is computer?
Computer is an electronic device used
to process data, converting the data into
meaningful information that is useful to
people.
Computer is an electronic device allows
inputting data process output and
storage device.

4. Block diagram of computer.
As you know computer is an electronic device it
comprises of many units these units work in coordination
with each other to perform the given task. Block diagram
of computer is show figure 1.1
Rifer this figure and note that computer comprises of
following units
1.Input unit.
2.Output unit.
3.input/output unit.
4.Central processing unit{CPU}
a)Memory unit
b)Arithmetic and logic unit{ALU}
c)Control unit.

5. How many parts of computer
Input unit
System
unit
Output
unit
1. Keyboard
2. Mouse
3. Microphone
4. Scanner
1. Processor
2. Motherboard
3. Ram & Rom
1. Monitor
2. Printer
3. speaker

6. Input units
1.keyboard:-keyboard consist of many keys.keys have
alphabets, numbers, characters or words written on
them .
Keys
Keys of the keyboard are broadly classified into following
categories:
A)Alphabet keys=A-Z
B)Number keys=1-0
C)Special character keys=@${}
D)Function keys=f1-f12
E)Cursor keys=
F)Action keys= shift, del, ctrl, alt, insert, etc

7. 2.mouse:- is an input device it is shown 1.4
figure. It looks like a real mouse with few
buttons placed on its back . when mouse is
connected to the computer an arrow sign
appears on the monitor screen. this sign is
called mouse pointer.

8. 3.CD-Rom:-CDis acronym for(compact disk)it works as a medium for
storing data or instructions it looks like circular plastic disk
CD-ROM drive is an input unit that reads data from CD, as the name
indicates, CD-ROM (compact disk read only memory)can only read
data from CD, it can’t write on it .
CD and CD-ROM drive are shown in figure 1.5
Part’s of CD.
There are two part’s of the CD.
A)CD-R=compact disk read.
B)CD-RW=Compact disk Re-writeable.
What Is the Difference between CD and DVD?
CD, short for Compact Disc, is an optical medium that can store
digital data. Usually, a standard CD can store about 700MB of data.
Digital Versatile Disc, is also an optical medium to store digital data.
A standard DVD can hold 4.7 GB of data. So DVD is widely used to
store large files like video and movies. The capacity is the biggest
difference between CD and DVD.

9. 4.light pen:-looks like an ordinary pen and performs same
function in computer world, which an ordinary pen does in
physical world
you hold the pen and write on a special pad or directly on the
screen.
5.Touch screen:-are special screen ,which are touch
sensitive ,when you touch a part of the screen they are
able generate information that the screen has been
touched and that too, on particular location

10. 6.Joystrick:-consists of a lever placed vertically in the middle of small
board, the lever can be moved in any desired direction,
joystick also contains few buttons.
When joystick is connected to the computer, many game applications take
input through joystick .when you move the lever of the joystick, objects in
the game(like ship , bird, car etc)also move.
7.Bar code reader:-is basically an input device it is used for reading bar
codes that appear on the wrappers of the objects like toothpasters, soaps,
biscuits back over of the books etc.
When bar code reader is move over the bar the bar code , pressing a
button ,it emits light (laser beam)

11. 8.Scanner:- is a device that scans pictures , maps photos,
documents etc.
9.OCR:-optical character reader it can be converted into
document file , which could either be edited through a text
editor(like notepad wordpad etc) or word processing software
like ms word, word perfect etc.

12. 10.MICR:-magnetic ink character reader is an input device which
reads special characters , written using magnetic ink best
example of magnetic ink characters is the cheque numbers that
are written on modern cheques.
11.OMR:-optical mark readers are special type of input devices
that read a document on which an optical mark has been pet to
understand the usage and concept .

13. 12.Microphone:-is an input device using which speech input is
provided to the computer.
These days , microphones are being widely used for internet
telephony , video conferencing
voice mail , voice chat etc.
“sound recorder” application of windows provides facility for
recording the sound in computer and introducing few special
effects in it.

14. 13.Web camera:-is an input device which captures live
movements and provides them as input to the computer.
14.Digita camera:-is a device which captures high-resolution
images and stores them in its memory , in digital form .