IT_1-2-3x - Wafanet.net

INFORMATION TECHNOLOGY

DEFINITIONS

Computer:

A computer is an electronic machine that receives input,
stores and automatically processes data, and provides
output in a useful format.



Data:

Data is raw & unorganized facts and figures that need to be
processed.




DEFINITIONS

Information:

When data is processed and organized so as to make it
useful and meaningful, it is called Information.


Information Technology:

A term that refers to both the hardware and software that
is used to store, retrieve and manipulate information.



ADVANTAGES OF COMPUTERS


Speed and accuracy of calculations and processing.


Save huge amounts of data.


Economic in cost and time.


Network communications.



COMPUTER GENERATIONS

1
st

Generation (Vacuum Tubes)


Very huge in size
.


Very expensive.


Very low processing speed.


Relied on the machine

language to perform operations.



COMPUTER GENERATIONS

2
nd

Generation (Transistors)


Smaller


Faster


Cheaper

COMPUTER GENERATIONS

3
rd

Generation (Integrated Circuits)


The speed and the efficiency of the computers were
increased.


COMPUTER GENERATIONS

4
th

Generation (Present Microprocessor)


Most powerful.


Can be linked together to form networks.


Fastest and most efficient.



TYPES OF COMPUTER

SUPER COMPUTER


Biggest and most powerful.


Rare because of their cost and size.


Used by companies like NASA.


MAINFRAME COMPUTER


Great processing speed and data storage.


Often connected to many individual PCs with limited
processing capabilities called dumb terminals.


Used in Banks, Airlines etc.

MINICOMPUTER



A Midsize Computer not very common now.



Minimized in size and power.



Can connect up to
200
users at a time.

MICROCOMPUTER


Also called
Personal
Computer
(PC)


Small
enough to fit on top of a desk, which can be
used by one user at a time
.


Used in homes, schools
etc.





WORKSTATION COMPUTER


High
-
end

microcomputer.


Used by one person at a time.


Commonly connected to a

local area network.

CONTROL COMPUTER


Used for controlling operations in industrial, medical
devices and travel media like planes and cars


Also used to alert in any dangerous case.

PARTS OF A PERSONAL
COMPUTER

Computer

Hardware

Software

DEFINITIONS

Hardware:

The physical parts of a computer which you can see
and touch.

Hardware

1
) Input
Devices

2
) Output
Devices


3
) Processing
Unit


4
) Memory
Unit

5
) Storage
Devices

HARDWARE

1
) Input Devices:
Devices used to
translate the data into a form that the
computer can process.


a) Keyboard

It

is

a

board

containing

the

keys

of

letters,

numbers

and

some

functions

which

allows

you

to

type

information

into

the

computer
.

b) Mouse

A

small

hand
-
held

device

used

to

point,

select,

click

on

items

and

to

drag

and

drop

items

from

one

place

to

another
.

c) Scanner

It allows you to scan pictures, text and images and
save it to your computer in a digital form.

d) Bar Code Reader

Photoelectric scanners that translate the bar code
symbols into digital form.

e) Joystick


Small

hand
-
lever

that

can

be

moved

in

any

directions

to

control

movement

on

the

screen
.


It

can

be

used

for

playing

games
.


HARDWARE

2
) Output Devices:
Devices used to
translate the processed information into a
form that humans can understand.


a) Monitor (computer screen)


It

displays

the

text,

information

and

pictures
.



They

are

different

in

(Size

and

Resolution)

b) Printer

It produces a hard copy of the material you are
working on.

Types:

1
) Laser Printer
2
) Ink
-
jet Printers

c) Plotters

It is similar to a printer but allows you to print larger
images.

d) Speakers / Headphone

They

are used to output voice from a computer

NOTE:

Some devices can be used as both Input and output
devices at the same time such as

Touch Screen:

It receives input from the touch of a finger.




HARDWARE

3
) Processing unit

(CENTRAL PROCESSING UNIT)



The most important part of a computer system.


Referred to as the brain of the computer.


Determines the speed of computer which is
measured in
MHz

or
GHz
.

1
GHz=
1000
MHz


CPU (Central Processing Unit )

CPU consists of:


CU (Control Unit):
It tells the computer
system how to carry out program instructions from
the memory. It controls and coordinates all activities
of the computer.



ALU (Arithmetic and Logic Unit):

It
performs mathematical and logical operations

HARDWARE

4
) Memory unit


Memory

RAM

ROM

RAM (Random Access Memory)


The operating system is loaded into the RAM when
you switch on your computer.


Used to store applications that you are currently
working with.


It is temporary
(volatile)
.



ROM (Read Only Memory)


It has special programs which are built
-
in when you
buy the computer.


Used to store control programs.


It is permanent
(non
-
volatile)
.

HARDWARE

5
)
Storage Devices:
Hardware devices which
are used to record and store data.


1
) INTERNAL STORAGE

HARD DISK


It is the most important storage media in the
computer.


It stores operating system and programs.

2
) EXTERNAL STORAGE

A compact and easy
-
to
-
use device for transferring data
between computers.

a) Flash Memory

b) CD (Compact Disk)


An

optical

disk

which

uses

laser

to

read

information
.


It

has

750

MB

capacity
.

c) DVD (Digital Versatile Disk)



A

high
-
density

video

disc

that

stores

large

amounts

of

data,

especially

high
-
resolution

audio
-
visual

material

like

movies,

encyclopedia

etc
.


The

capacity

is

up

to

17

GB
.

DISK AND MEMORY CAPACITY

The first level of storage is called
bit

(the bit is
referred to a binary number
0

or
1
).

Byte

=
8
bits.

Kilo Byte (KB)
=
1024
bytes.

Mega Byte (MB)
=
1024
KB.

Giga Byte (GB)
=
1024
MB.

Tera

Byte (TB)
=
1024
GB.

COMPUTER PERFORMANCE

1.
The speed of the processor.

2.
The capacity of RAM.

3.
The capacity and the speed of the Hard
disk.

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