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orangesvetElectronics - Devices

Nov 8, 2013 (3 years and 9 months ago)

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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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