PST SC015 Chapter 2 Computer System (II) 2017/2018

1
Computer System
Chapter Two
2.5 Hardware
2.5.1 Motherboard
2.5.2 Processor
2.5.3 Memory
2.5.4 Input and Output Device
2.5.5 Storage
2.5.6 Adapter Card

Hardware
2
Subtopic Description
2.5.1 Motherboard Motherboard is the main circuit board of the system unit, that contains
integrated circuits
2.5.2 Processor Interprets and carries out the basic instructions that operate a computer
2.5.3 Memory Memory consists of electronic components that store instructions waiting
to be executed by the processor, data needed those instructions, and the
results of the processing data
2.5.4 Input and Output
device
Input device - any hardware component allows users to enter data and
instructions into a computer
Output device - any hardware component allows users to enter data and
2.5.5 Storage Computer hardware that records and/or retrieves items to and from
storage media. Its to store data and programs when they are not being
processed
2.5.6 Adapter card Enhances functions of a component of the system unit and/or provides
connections to peripherals

Hardware
3
Component of Hardware Description
Input Device any hardware component allows users to enter data and
Output Device any hardware component that conveys information to one
or more people
System Unit Is a case that contains electronic components of the
computer used to process data
Storage Device is the computer hardware that records and/or retrieves
items to and from storage media
Communication Device Enables a computer to send and receive data,
instructions, and information to and from one or more
computers or mobile devices
● A computer contains many electric, electronic, and
mechanical components known as hardware

•
Instructions can be entered into the computer in the
form of programs, commands, and user
responses A program is a series of related
instructions that tells a computer what
tasks to perform and how to perform
them
Programs respond to commands that a
user issues
A user response is an instruction a user
issues by replying to a question
displayed by a program
4

Computer System
Chapter Two
2.5.4 Input and Output Device
At the end of this topic, students
should be able to:
a)Identify the input and output device
b)Explain the functions of input and output
devices
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3
● any hardware component allows users to enter data
and instructions into a computer
● Voice input : process of entering input by speaking into
a microphone
● Audio input : process of entering any sound into the
computer such as speech, music and sound effects
● Video input : process of capturing full-motion images
Define Input Device
2

•
1.
2.
Keyboard
Pointing device
•
•
•
•
•
Mouse
Trackball
Touchpad
Joystick
Stylus
3. Digitizer
•
•
Graphics Tablet
Scanner
4. Microphone
6
Examples of Input Device
3

5.
6.
7.
8.
9.
Webcam
Touch screens
Joystick
Digital Camera
Reading devices
Character•
•
•
•
Optical
Optical
Recognition (OCR)
Mark Recognition (OMR)
Magnetic-Ink Character Recognition (MICR)
Biometric input device
7
Examples of Input Device
4

The Keyboard
•
A keyboard is an input device that contains keys
Page 260
Figure 5-2
8
Discovering Computers : Chapter 5
users press to enter data and instructions into a
computer
5

Keyboard
Types:
1. Desktop computer keyboard
2. Keyboard for mobile devices 3. Keyboard ergonomics
9
6

Pointing Devices
A pointer is a small
symbol on the
screen
whose location and
shape change as a user
moves a pointing device
A pointing device is an
input device that allows
a user to control a
pointer on the screen
Page 263 10
7

Mouse
• Mouse is a pointing device that fits under
the palm of your hand comfortably
11
8

Other Pointing Devices
• A trackball is a
stationary
pointing
device with a
ball on its top
or side
• A touchpad is
a small, flat,
rectangular
pointing
device that is
sensitive to
pressure and
motion
•A pointing
stick is a pressure-
sensitive pointing
device shaped like
a pencil
eraser that
is positioned
between keys on
a keyboard
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Trackball
Touchpad
PointingStick
9

Touch Screens and Touch-Sensitive
Pads
•
A touch screen touch-sensitive display device
13
10

Microsoft Surface Touch-sensitivepads
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Touch Screens and Touch-Sensitive
Pads
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Pen Input
•
With pen input, you touch a stylus or digital pen on a flat
surface to write, draw or make selections
15
12

Other Input for Smart Phones
16
13

Game Controllers
•
Video games and computer games use a game controller
as the input device that directs movements and actions
Joysticks and
WheelsGamepads
Light guns Dance pads
Motion-
sensing controllers
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14

Web Cam
•
A Webcam is a type of digital video camera that
enables a user to:
Send e-mail
messages with
video attachments
Capture video and
still image
Add live images to
instant messages
Broadcast live
images over the
Internet
Make video
telephone calls
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15

Other Input Devices
–
Digital camera is a mobile device that allows
users to take pictures and store them digitally
– Microphone
• allows to speak into the computer
– Scanner
• converts printed material (text and
picture) into a form the computer can
used.
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16

Scanners and Reading Devices
•
Optical character recognition (OCR) involves reading
characters from ordinary documents
•
A turnaround document is a document you return to the
company that creates and sends it
20
17

- Optical mark
recognition (OMR)
reads hand-drawn
marks such as small
circles or rectangles
- An OMR device scans
the documents and
matches the patterns of
light matches
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18

•
A bar code reader, also
called a bar code scanner
uses laser beams to read
bar codes.
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- RFID (radio frequency identification) uses radio signals to
communicate with a tag placed in or attached to an object
- An RFID reader reads information on the tag via radio waves
- RFID can track:
Tracking times of
runners in a
marathon
Tracking location
of soldiers
Employee
wardrobes
Checking lift
tickets of skiersAirline baggage
Gauging pressure
and temperature
of tires
Managing
inventory
Checking out
library books
Tracking toll
payments
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20

•
Magnetic stripe card readers read the magnetic
stripe on the back of cards such as :
Credit cards
Entertainment cards
Bank cards
Other similar cards
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21

- MICR (magnetic ink character recognition) devices read
text
printed with magnetized ink
- An MICR reader converts MICR characters into a form the
computer can process
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- Banking industry uses MICR check processing
22

•
Data collection devices
obtain data directly at
the location where the
transaction or event takes place
Used in:
•
Restaurants, Grocery stores,
Factories,Warehouse
The outdoors
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Biometric Input
•
Biometrics authenticates a person’s identity
byverifying a personal characteristic
Hand geometry
system
Voice
verification
system
Signature
verification
system
Iris recognition
system
Retinal
scanners
27
Fingerprint
reader Face Recognition
System
24

Biometric Input
28
fingerprint
reader
iris
recognition
system
hand
geometry
system
25

Terminals
•
A terminal is a computer that allows users to send data to
and/or receive information from a host computer
A POS terminal
records purchases,
processes
payment, and
updates inventory
An automated
teller machine
(ATM) allows users
to access their
bank accounts
A DVD kiosk is a
self-service DVD
rental machine
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26

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Input Device
Type / example Function
Keyboard
- Desktop computer keyboard
- Keyboard for mobile device
- Keyboard ergonomics
Is an input device that contains keys users press to
enter data and instructions into a computer
● Ergonomic keyboard - Is an input device that
designed with ergonomic considerations to minimize
muscle strain and a host of related problems.
Pointing device
- Mouse
- Trackball
- Touchpad
- Joystick
- Pointing stick
Is an input device that allows a user to control a pointer
on the screen
● Mouse - a pointing device that fits under the palm
of your hand comfortably
● Trackball - a pointing device with ball on its top or
side
● Touchpad - a pointing device that is sensitive to
pressure and motion
● Pointing stick - a pointing device shaped like a
pencil eraser that is pressure sensitive
Input Device : Summary
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3
Input Device
Digitizer
- Graphic tablet
- Scanner
● Graphic tablet - Is an input device that allows a user
to hand-draw images, animations and graphics, with
a special pen-like stylus, similar to the way a person
draws images with a pencil and paper.
Scanner - Is an input device that allow user to
converts printed material (text and picture) into a
form the computer can used
Microphone Is an input device that allow user to speak into the
computer
Webcam Is an input device that allow user to capture videos and
images,make video phone calls, broadcast live images
over the internet
Touch screen Is an input device that sensitive to pressure; a user
interacts with the computer by touching pictures or words
on the screen.
Digital camera Is an input device that allow user to take pictures and store
them digitally
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3
Reading device
- Optical Character
Recognition (OCR)
- Optical Mark Recognition
(OMR)
- Barcode reader
- RFID
- Magnetic stripe card
reader
- MICR
- Biometric input device
● OCR - Is an input device that allow user to read characters from
ordinary documents
● OMR - Is an input device that allow user to scans the hand
drawn mark documents and matches the patterns of light
● Barcode reader - Is an input device that allow user to read
barcode by using laser beam
● RFID - (radio frequency identification) Is an input device that
allow user to reads information on the tag via radio waves. Eg :
tracking times of runners in a marathon, tracking location of
soldiers
● Magnetic stripe card reader - Is an input device that allow user
to read the magnetic stripe on the back of card such as credit
cards, bank cards
● MICR - (magnetic ink character recognition) Is an input device
that allow user to read text printed with magnetized ink. (clue :
bank check)
● Biometric input device - Is an input device that allow user to
authenticates person’s identity by verifying a personal
characteristic 29

3
Input Device
Terminals Is an input device that allow user to send data to/or
receive information from a host computer.
Eg : a post terminal, ATM (automated teller machine), a
DVD kiosk
Game controllers
- Gamepads
- Joysticks and wheels
- Light guns
- Dance pads
- Motion-sensing controllers
Is an input device that directs movements and actions of
on-screen objects
30

Define Output Device
• An output device is any type of hardware
components that conveys information to one or
more people
Speakers,
headphones,
and earbuds
Display devices Printers Data projectors
Force-feedback
game
controllers
Interactive
whiteboards Tactile output
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Display Devices
•
•
31
32
A display device
visually conveys
text, graphics and
video information
A monitor is
packaged as a
separate peripheral
- LCD monitor
- Widescreen

Display Devices
•
A CRT monitor is a desktop monitor that contains
a cathode-ray tube
–
Have a much larger footprint than do LCD monitors
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Display Devices
•
•
•
Page 312
Figure 6-9
33
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Television also are good output
device
- require a converter if you are
connecting your computer to an
analog television
Digital television (DTV) offers a
crisper, higher-quality output
HDTV is the most advanced
form of digital television

Printers
•
A printer produces text and
graphics on a physical medium
– Printed information is called a
hard copy, or printout
– Landscape or portrait
orientation
Examples: ink-jet printers, dot-
matrix printers, photo
printers, laser printers, thermal
printers, mobile printers, label
and postage printers, plotters,
and large-format printers.
•
Page 313
Figure 6-11
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Printer
Large-format printer
Dot-matrix printer
Label and postage printer
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Speakers, Headphones, and Earbuds
•
•
•
•
•
Page 323
Figure 6-26
Discovering Computers : Chapter 6 36
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Most computer users attach speakers to their
computers to :
● Generate higher-quality sounds for playing games
● Interact with multimedia presentations
● listen to music
● view movies
An audio output device produces music,
speech,or other sound

•
•
Page 324
Figure 6-27
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Speakers, Headphones and Earbuds
Headphones are
speakers that cover or
are placed outside of
the ear
Earbuds (also called
earphones) rest inside
the ear canal.

•
Some speakers are specifically designed to play
audio from a portable media player
–
Wireless speakers
Page 324
Figure 6-28
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Voice output occurs when you hear a person’s
voice or when the computer talks to you through
the speakers
-Some Web sites dedicate themselves to
providing voice output
- Often works with voice input
- VoIP uses voice output and voice input
Page 325 Discovering Computers : Chapter 6 39
40

Other Output Devices
•
Other output devices are available for specific
uses and applications
Interactive
whiteboardsData projectors
Force-
feedback
game
controllers
Tactile
output
40
Touch screen
monitor
41

•
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A data projector is
a device that takes
the text and images
displaying on a
computer screen
and projects them on
a larger screen
- LCD projector
- Digital light
processing (DLP)
projector

•
42
43
An interactive whiteboard is a touch-sensitive device,
resembling a dry-erase board, that displays the image
on a connected computer screen.

•
•
43
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Force-feedback send
resistance to the device
is response to actions
of the user.
Tactile output
provides the user with
a physical response
from the device

• A touch screen monitor is a monitor
screen that can detect and respond to
something, such as a finger or stylus, pressing
on it.
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Output Device : Summary
Type Description
Display device
- LCD monitor
- CRT monitor
- Plasma monitor
An output device that convey information to
the user in the form of text, graphics and
video
LCD monitor : is a desktop monitor that used
liquid crystal display to produce images
CRT monitor : is a desktop monitor that
contains a cathode ray tube
Plasma monitor : is a display device that uses
gas plasma technology
2846

3
Type Description
Printers
- Ink-jet printer
- Dot-matrix printer
- Photo printers
- Laser printers
- Thermal printers
- Mobile printers
- Label and postage
printers
- Plotters
- large -format printers
the user in the form of text and graphics on a
physical medium (hard copy or print out)
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3
Type Description
Speakers, headphone, and
earbuds
the user in the form of music, speech and
other sounds
Voice output - occurs when you hear a
person’s voice or when the computer talks
through the speakers
Data projector
- LCD projector
- Digital light processing
(DLP) projector
An output device that takes the text and
images displaying on a screen and projects
them on a larger screen
Interactive whiteboard An output device that touch-sensitive device,
resembling a dry-erase board, that displays
the image on a connected computer screen 48

3
Type Description
Force-feedback game
controllers
An output device that send resistance to the
device in response to action of the user
Tactile output An output device that provides the user with a
physical response from the device
49

3
Input Output Devices
50
● A devices that can be both input and output
devices.
● Example :
○ Touch screen
○ Digital camera
○ Headsets - Headset consists of Speakers and
Microphone. Speaker act Output Device and
Microphone act as Input device
○ Facsimile (Fax Machine) - It has scanner to
scan the document and also have printer to
Print the document

Computer System
Chapter Two
2.5.1 Motherboard
should be able to:
a)Identify basic components of a motherboard.
1

System Unit
● A computer case is also known as a computer
chassis / tower / base unit / system unit
● also sometimes incorrectly referred to as the CPU
● The system unit is a case that contains electronic
components of the computer used to process data
● all computers and mobile devices have a system
unit
2

System Unit
The inside of the system unit on a desktop personal computer
includes :
3
Motherboard
Adapter cards
Processor
Memory
drive bays
processor
memoryports
sound card
video cardmodem cardnetwork card
power supply

Motherboard
● Motherboard is the main circuit board of the system unit, that contains
integrated circuits
4

Function of Motherboard
● Function of motherboard :
i. Holds many components of the system
Ii. provides connectors for other peripherals
5

Basic Component of Motherboard
6
Component Description
Processor slot Slot on the motherboard that houses a
CPU and forms the electrical interface
with the CPU
Adapter card slot Slot on the motherboard that can hold
adapter card
Memory slot Slot on the motherboard that hold
memory modules

Processor Slot
● Processor slot - slot on the motherboard that
houses a CPU and forms the electrical interface
with the CPU
7

Adapter Card Slot
● Adapter card slot - slot on the motherboard that
can hold adapter card
● For adding more memory, graphics capabilities
and support special devices
8

Memory Slot
● Memory slot - slot on the motherboard that hold
memory modules
9

Computer System
Chapter Two
2.5.2 Processor
should be able to:
a)Describe the functions of processor
b)list the steps in a machine cycle
1

Processor
● The processor, also called the central processing
unit (CPU), interprets and carries out the basic
instructions that operate a computer
● CPU speeds is measured in Gigahertz (GHz)
● Components of processor
- Control unit
- Arithmetic logic unit
2

Control Unit
● Is the component of the processor that directs and
coordinates most of the operations in the
computer.
● The control unit interprets each instruction issued
by a program and then initiates the appropriate
action to carry out the instruction.
3

Arithmetic Logic Unit
● Performs arithmetic, comparison and other
operations.
● Arithmetic operations include basic calculations such
as addition, subtraction, multiplication and division.
● Comparison (logical) operations involve comparing
one data item with another to determine whether
the first item is greater than, equal to or less than
the other item.
2
4

Machine Cycle
2
Step 1 : Fetch the control unit obtains the math problem’s instruction and
data from memory
Step 2 : Decode the control unit translates the math problem’s instructions
and sends the instructions and data to the ALU
Step 3 : Execute the ALU performs calculations on the data
Step 4 : Store the results of the math problem are stored in memory
(RAM)
● The operations performed by the CPU to execute any
instruction
● For each instruction, a processor repeats a set
of 4 basic operations, which comprise a machine cycle.
5

Machine Cycle
2
2. Decode
- Process of translating
the instruction into
signals the computer
can execute.
1. Fetch
- Process of obtaining a
program instruction or
data item from memory.
4. Store
- Writing the result to
memory.
3. Execute
- Process of carrying out
the commands.
6

Computer System
Chapter Two
2.5.6 Adapter Card
should be able to:
a)Identify types of adapter card
b)Explain the functions of adapter cards.
1

Expansion Slots and Adapter Cards
•
An expansion slot is a socket on the
motherboard that can hold an adapter card
An adapter card enhances functions of a
component of the system unit and/or provides
connections to peripherals
A peripheral is a device that connects to the
system unit and is controlled by the processor
in the computer. Examples : modems, printers,
scanners, keyboards, sound card and video card
•
•
2

adapter card
motherboard peripheral (printer) 3

Figure 4-27 An adapter card being inserted in an expansion slot on
the motherboard of a personal computer
4

FireWire
connector Firewire cardport
6
● Home users can transfer videos to their computers and then use video
editing software to edit the video.

MIDI
● connects the system unit to a musical instrument, such as
an electronic keyboard
7
peripheral (musical instruments)
MIDI card
port

USB
peripheral
(mouse)
USB
card
port
8

should be able to:
explain data representation in
computer
a)
1
Chapter Two
Computer System
2.1.2 Data Representation

Data Representation
How does a computer represent data?
❑ By using two unique binary digits 1 and 0 to
represent the two states on and off.
❑ A computer circuit represents the 0 or the 1
electronically by the presence or absence of
an electrical charge
computer recognizes only two discrete
electrical states (on and off)
2

Data Representation
Bit
▪ Is the smallest unit of data the computer can
process.
▪ (Short for binary digit )
▪ The number system has two unique digits, 1 (on)
or 0 (Off)
▪ Represents an electrical state (on or off)
Byte
▪ A group of 8 bits (ex:11110000)
▪ Represents a single character such as a digit,
a letter, a punctuation mark or any symbol in
computer 3

Data Representation
• ASCII (American
Standard Code for
Information
Interchange) is the
most widely used
coding scheme to
represent data
44

should be able to:
Identify the coding system used in data
processing
Differentiate the coding system
a)
b)
1
Chapter Two
Computer System
2.3 Information Coding Schemes

Information Coding Schemes
The combination of 0s and 1s that represent
characters are defined by pattern called a Coding
scheme.
Popular Coding Scheme
● ASCII (American Standard Code for Information Interchange)
● EBCDIC (Extended Binary Coded Decimal Interchange Code)
● Unicode (Uniform code capable of representing all world’s
Language)
2

Information Coding Schemes
3
ASCII EBCDIC Unicode
American Standard Code for
Information Interchange
Extended Binary Coded Decimal
Interchange Code
Universal character encoding
standard
Widely used to represent text
based on data for computer
processing on many types of
computers.
Traditionally used with
PCs.
based on IBM mainframe
computers
Primarily is used on mainframe
computers and high-end servers
based data using any written
language, including those in
different alphabets such as
Chinese, Greek and Russian
Use 8 bits to represent a
character
Can represent 256 characters
Use 8 bits to represent a
character
Can represent 256 characters
Use 16 / 32 bits to represent a
character
Can represent more than 65000
characters
Can work in many computer
system
Can work in many computer
system
Can work in several computer
systems, such as
Windows, Mac OS, Linux

1
Chapter Two
NUMBER SYSTEM AND
REPRESENTATION
2.2 Number System
2.2.1 Binary
2.2.2 Hexadecimal
2.2.3 Conversion Between Binary and
Hexadecimal

Define Number
System
● A set of numerals for representing
numbers
Decimal Numbers (base 10)
Binary Numbers (base 2)
Hexadecimal Numbers (base 16)
Page 260
Figure 5-2
8

Decimal Numbers
● Consists of numbers 0-9
● Decimal digits are joined together to form
longer decimal numbers
● Example: 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11,
12,………
● also known as the base 10 numbering system
8
6 1 5
6 x 10^2 1 x 10^1 5 x 10^0
6 x 100 1 x 10 5 x 1
600 + 10 + 5 = 615

should be able to:
represent data in binary forma)
1
Chapter Two
NUMBER SYSTEM AND
REPRESENTATION
2.2.1 Binary

Binary Numbers
● Machine recognises two states: 0 (off) and 1
(on)
● Binary number represents numeric values
using two symbols, 0 and 1
● Eg : 111000, 101 111 111
8

Comparison Between Decimal Number
and Binary Number
8
DECIMAL BINARY
0 0
1 1
2 10
3 11
4 100
5 101
6 110
DECIMAL BINARY
7 111
8 1 000
9 1 001
10 1 010
11 1 011
. .
40 101 000
. .

should be able to:
represent data in hexadecimal forma)
1
Chapter Two
NUMBER SYSTEM AND
REPRESENTATION
2.2.2 Hexadecimal

Hexadecimal Numbers
● Uses 16 symbols: 0,1,2, 3, 4, 5, 6, 7, 8, 9, A, B,
C, D, E and F.
● It can represent binary values in compact
form.
● 9B416
is example of hexadecimal numbers.
8

Comparison Between Decimal Number
and Hexadecimal Number
8
DECIMAL HEXADECIMAL
0 0
1 1
2 2
3 3
4 4
5 5
6 6
7 7
8 8
9 9
DECIMAL HEXADECIMAL
10 A
11 B
12 C
13 D
14 E
15 F
16 10
17 11
20 14
35 23

8
Decimal Hexadecimal Binary
0 0 0
1 1 1
2 2 10
3 3 11
4 4 100
5 5 101
6 6 110
7 7 111
8 8 1000
9 9 1001
10 A 1010
11 B 1011
12 C 1100
13 D 1101
14 E 1110
15 F 1111
Comparison Between Number System

should be able to:
a. convert from binary to hexadecimal
b. convert from hexadecimal to binary
1
Chapter Two
NUMBER SYSTEM AND
REPRESENTATION
2.2.3 Conversion Between Binary and Hexadecimal

Conversion Between Number System
● Decimal to Binary
● Binary to Decimal
● Decimal to Hexadecimal
● Hexadecimal to Decimal
● Binary to Hexadecimal
● Hexadecimal to Binary
8

CONVERSION
Decimal to Binary conversion

Binary
number
2
2 ---- 0
---- 1
2
2
---- 1
---- 0
22
11
5
2
1
0 ---- 1
Hence, 22 = 10110 2
Eg 1: Convert the number 22 to the binary
number system. Solution : 22
=
2
2
Write from bottom to
top → left to right
Decimal to binary conversion

Eg 2: Convert the number 40 to the
binarynumber system. Solution : 40 =
2
2
2
2
2
2
2
40
20
10
5
2
1
0
---- 0
---- 0
---- 0
---- 1
---- 0
---- 1
Binary
number
Hence, 40 = 101000
2

2
2
2
2
2
18
9
4
2
1
0
---- 0
---- 1
---- 0
---- 0
---- 1
Binary
number
Hence, 18 = 100102
Eg 3:Express 18 in binary number form
Solution 18 = 2

CONVERSION
Binary to Decimal conversion

● In binary number, the column weights
(again from right to left) are as follows:
● Eg : convert 1011 2 to decimal number
Binary to Decimal conversion
1 0 1 1
1 x (2^3) 0 x (2^2) 1 x (2^1) 1 x (2^0)
1 x 8 0 x 4 1 x 2 1 x 1 Decimal number
8 0 2 1
8+0+2+1=1110
Binary to decimal conversion
CONVERSION
decimal

Hence, 10110 2 = 22
Eg 1: Convert the binary number 10110 2 to
decimal number
Solution:
1 0 1 1 0
1 x 2^4 0 x 2^3 1 x 2^2 1 x 2^1 0 x 2^0
2210
1 x 16 0 x 8 1 x 4 1 x 2 0 x 1
16 0 4 2 0
16 + 0 + 4 + 2 + 0 =
CONVERSION
decimal

Eg 2 :Convert the binary number 1011100 2
to decimal number
Solution:
Hence, 1 011 100 2 = 92
1 0 1 1 1 0 0
1 x 2^6 0 x 2^5 1 x 2^4 1 x 2^3 1 x 2^2 0 x 2^1 0 x 2^0
9210
1 0 1 1 1 0 0
1 x 64 0 x 32 1 x 16 1 x 8 1 x 4 0 x 2 0 x 1
64 + 0 + 16 + 8 + 4 + 0 + 0
=
CONVERSION
decimal

CONVERSION
Decimal to Hexadecimal
conversion

16
16
16
1341
83
5
0
---- 3
---- 5
Eg 1: Convert the decimal number 1341 to
hexadecimal number
Hence,1341 = 53D16
Decimal to hex conversion
Hex Number
---- 13 = D

Eg 2 : Convert the decimal number 860 to
hexadecimal number
16
16
16
860
53
3
0
---- 12 = C
---- 5
---- 3
Hence, 860 = 35C16
Hex Number

16
16
16
2020
126
7
0
---- 4
---- 14 = E
---- 7
Eg 3 : Convert the decimal number 2020 to
hexadecimal number
Hex Number
Hence, 2020 = 7E416

CONVERSION
Hexadecimal to Decimal
conversion

to decimal number● Convert
AFB216
Solution:
Hence, AFB216 =
44978
Eg 1 : Convert the hex number, AFB216
to decimal number
A F B 2
A x 16^3 F x 16^2 B x 16^1 2 x 16^0
4497810
10 x 4096 15 x 256 11 x 16 2 x 1
40960 + 3840 + 176 + 2 =
hex to decimal conversion
CONVERSION
Eg 1: Convert the number AFB16 to the
decimal

to decimal number● Convert
BA816
Solution:
Hence, BA816 =
2984
Eg 2 : Convert the hex number, BA816
to decimal number
B A 8
B x 6^2 A x 16^1 8 x16^0
298410
11 x 256 10 x 16 8 x 1
2816 + 160 + 8 =
CONVERSION
Eg 2: Convert the number BA816 to the
decimal

to decimal number● Convert AFFA16
Solution:
Hence, AFFA16 =
45050
Eg 3 : Convert the hex number, AFFA16
to decimal number
A F F A
A x 16^3 F x 16^2 F x 16^1 A x16^0
4505010
10 x 4096 15 x 256 15 x16 10 x
1
40960 + 3840 + 240 + 10 =
CONVERSION
Eg 3: Convert the number AFFA16 to the
decimal

CONVERSION
Binary to Hexadecimal
conversion

Binary to Hexadecimal conversion
● There are two ways on how to convert
the
binary to hexadecimal number.
● 1st way : Decimal
Hexadecimal
○ Binary
○ 2nd way :
○ Binary Hexadecimal
binary to hex conversion

Eg. 1: Convert the binary number 110102 to
hexadecimal 1st way
○ Binary Decimal
26
1
16
16
0
---- 10 = A
---- 1
Decimal Hexadecimal
Hence, 11010 2 = 1A16
1 1 0 1 0
1 x 2^4 1 x 2^3 0 x 2^2 1 x 2^1 0 x 2^0
26
1 x16 1 x8 0 x 4 1 x 2 0 x 1
16 + 8 + 0 + 2 + 0 =
hexadecimal 1st way

● Step 1: divide the given binary digit into 4 digit per
group from right to left.
1 1 0 1 0
● Step 2: Using 8421 table,
1 1 0 1 0
1
= 1
8 4
2
1
8 + 2
= 10
= A
8 4 2 1
Hence, 11010 2 =
1A16
hexadecimal 2nd way

Binary Decimal
18
1
0
---- 2
---- 1
Decimal
16
16
Hexadecimal
Hence, 100102 = 1216
Hex number
Eg.2 :Convert the binary number 100102 to
hexadecimal 1st way
1 0 0 1 0
1 x 2^4 0 x 2^3 0 x 2^2 1 x 2^1 0 x 2^0
18
1 x 16 0 x 8 0 x 4 0 x 2 0 x 1
16 + 0 + 0 + 2 + 0 =
hexadecimal 1st way

Eg.2 :Convert the binary number 100102 to
hexadecimal 2nd way
● Step 1: divide the given binary digit into 4 digit per
group from right to left.
1 0 0 1 0
● Step 2: Using 8421 table,
1 0 0 1 0
1
= 1
8 4
2
1
2
= 2
8 4 2 1
Hence, 11010 2 =
1216

CONVERSION
Hexadecimal to Binary
conversion

Hexadecimal to Binary conversion
● There are two ways on how to convert
the
hexadecimal to binary number.
● 1st way : Decimal
Binary
○ Hexadecimal
○ 2nd way :
○ Hexadecimal Binary

Eg 1: Convert the hexadecimal number
3FD to binary number 1st way
Hexadecimal Decimal
16^2 16^1 16^0
1021
3 F D
256 x3 16 x15 1 x 13
768 + 240 + 13 =
hex to binary conversion
Eg. 1: Convert the hexadecimal number
3FD16 to binary number 1st way
Hexadecimal Decimal

Binary number
De
2
2
2
2
1021
510 ---- 1
255 ---- 0
127 ---- 1
2 63 ---- 1
2 31 ---- 1
2 15 ---- 1
2 7 ---- 1
2 3 ---- 1
2 1 ---- 1 Hence, 3FD16 = 11111111012
0 ---- 1
cimal Binary
3FD16 to binary number 1st way

3FD to binary number 2nd way
Hence, 3FD16 = 11111111012
=8+4+1
= 13
=8+4+2+1
= 15
=2+1
= 3
3 F = 15 D = 13
3 15 13
8 4 2 1 8 4 2 1 8 4 2 1
0 0 1 1 1 1 1 1 1 1 0 1
3FD16 to binary number 2nd way

Eg 2: Convert the hexadecimal number 1A2
to binary number 1st way
Hexadecimal Decimal Decimal Binary
2
2
2
2
2
2
2
2
2
2
---- 0
---- 1
---- 0
---- 0
---- 0
---- 1
---- 0
---- 1
---- 1
Hence, 1A216 = 1101000102
1 A 2
1 x 16^2 A x 16^1 2 x 16^0
418
1 x 256 10 x 16 2 x 1
256 + 160 + 2 =
418
209
104
52
26
13
6
3
1
0
1A216 to binary number 1st way
DecimalHexadecimal Decimal Binary

1A2 to binary number 2nd way
=2=8+2
= 10
=1
Hence, 1A216 = 1101000102
1 A 2
1 10 2
8 4 2 1 8 4 2 1 8 4 2 1
0 0 0 1 1 0 1 0 0 0 1 0
= 2= 8 + 2
= 10
= 1
1A216 to binary number 2nd way

UPS 2015/2016
Q: Given the Internet Protocol address of a
printer as 192.0.0.2. Convert the address to
hexadecimal number [2 marks]
A: C0.0.0.2

Computer System
Chapter Two
2.5.3 Memory
should be able to:
a)Describe the function of the memory
b)Differentiate between volatile and nonvolatile
memory
c)Identify different types of memory
1

Memory
3
●Memory consists of electronic components that
store instructions waiting to be executed by the
processor, data needed those instructions, and the
results of the processing data
●Each location in memory has an address
●Memory size is measured in KB (Kilobyte), MB
(Megabyte), Gb (Gigabyte) or TB (Terabyte). (* refer
to 2.1.3 storage capacity)
2

Discovering Computers 2012: Chapter 4 4
Figure 4-20
RAM chips usually reside on a
memory module and are
inserted into memory slots
3

Types of memory
Memory
NonvolatileVolatile
5
4

Volatile memory
• When the computer’s power is turned off,
volatile
Volatile
RAM is
memory loses its contents.
memory is temporary.•
• the most common type of volatile
memory
6
5

Volatile memory : RAM
• RAM chips usually reside on a memory module
and are inserted into memory slot
• The amount of RAM necessary in a computer often
depends on the types of software you plan to use
9
6

Three basic types of RAM
Discovering Computers 2012: Chapter 4 10
DRAM
(Dynamic RAM )
SRAM
(Static RAM )
MRAM
(Magnetoresistive
RAM)
• Chips must be re-
energized constantly or
they lose their contents.
• Chips are faster and
more reliable than any
variation of DRAM chips.
• A newer type of RAM,
called magnetoresistive
RAM (MRAM pronounced
EM-ram), stores data using
magnetic charges instead
of electrical charges
7

Nonvolatile Memory
● Nonvolatile memory does not lose its
contents
● when power is removed from the computer.
● Nonvolatile memory is permanent and
cannot modified.
● Eg : ROM
7
8

Nonvolatile Memory : ROM
• Read-only memory (ROM) refers to memory chips
storing permanent data and instructions.
• The data on most ROM chips cannot be modified.
11
9

8
Volatile (RAM) Nonvolatile (ROM)
Temporary : loses its contents when
the power is turned off
Permanently : Does not lose contents
when the power turned off
Can be read from and written to by the
processor and other device
Data is prerecord for read only and
cannot be modified or removed
Hold data or programs that are
currently being used by the processor
Contain a small startup program
(BIOS) which is used to boot the
computer
RAM chip usually reside on a memory
module and are inserted onto the
memory slot
Exist as a chip on the motherboard
Differences Between Volatile and
Nonvolatile
10

Types of ROM
12
PROM
(Programmable Read-
Only Memory)
EPROM (Erasable
Read-Only Memory)
EEPROM (Electrically
Erasable
Programmable Read-
Only Memory)
• Is a blank ROM chip
on which a programmer
can write permanently.
● These chips can be
erased and rewritten a
number of times.
• Allows a programmer
to erase the microcode
with an electric signal
11

should be able to:
a)
b)
c)
Identify storage media
Explain the functions of storage media
Differentiate between memory (RAM) and
storage
1
Chapter Two
Computer System
2.5.5 Storage

Storage
Storage holds data, instructions, and
information for future use
A storage medium / media is the physical
material on which a computer keeps data,
instructions, and information
2
2

should be able to:
Differentiate various storage capacitya)
1
Chapter Two
Computer System
2.1.3 Storage Capacity

2
Storage Capacity
• Capacity is the number of bytes a storage
medium
can hold

3
Capacity Storage Measured in
● Kilobyte = 1,024 bytes
● Megabyte = 1,024 Kilobyte
● Gigabyte = 1,024 Megabyte
● Terabyte = 1,024 Gigabyte
● Petabyte = 1,024 Terabyte

4
Conversion unit of Capacity Storage
1200 MB = 1200 / 1024
= 1.17 GB
1200 MB = 1200 / 210
= 1.17 GB
1 GB = 1 x 1024 x 1024
= 1 048 576 KB
1 GB = 1 x 210 x 210
=1 048 576 KBOR
OR
P
B
E
B
ZB YBTBGBMBKBBit (b) Byte
(B)
÷
8
÷ 210
÷ 210
÷ 210
÷ 210
÷ 210
÷ 210
÷ 210
÷ 210
x 210
x 210
x 210
x 210
x 210
x 210
x 210
x 210x
8

Define Storage Device
● A storage device is the computer hardware that records and/or
retrieves items to and from storage media
● It’s function is to store data and programs when they are not
being processed
● Stores data permanently
● Available in the form of hard disk, CD, USB drive. etc
7
3

Reading is the process of
transferring items from a storage
medium into memory
Writing is the process of
transferring items from memory to
a storage medium
Page 354
8
4

Types of Storage
9
● Magnetic Storage
● Optical Storage
● Flash Memory
5

Magnetic Storage
10
Type Description
Magnetic
storage
- Uses different patterns of magnetization
on a magnetically coated surface to store
information
- Eg :
Hard disk Floppy disk
6

Magnetic Storage : Hard Disk
•
11
7
A hard disk contains one or more inflexible,
circular platters that use magnetic particles to
store data, instructions and information.

Hard Disks
An external hard disk is a separate free-
standing hard disk that connects to your
computer with a cable or wirelessly
A removable hard disk is a hard disk
you insert and remove from a drive
that
Internal and
in miniature
external hard disks are available
sizes (miniature hard disks)
12
8

– Stores information in deformities on the surface of
a circular disc and reads this information by
andilluminating the surface with a laser diode
observing the reflection.
– Types of optical disc are:
» Compact Disc (CD)
» Digital Video Disc
» Blu-ray Disc (BD)
(DVD)
13
Optical Discs Storage
9

A CD-ROM can be read from but not written to
• Read from a CD-ROM drive or CD-ROM player
A CD-R is a multi session optical disc
on
users can write, but not erase
which
A CD-RW is an erasable multisession
• Must have a CD-RW drive
disc
14
10

A DVD-ROM is a high-capacity optical disc on
which users can read but not write or erase
• Requires a DVD-ROM drive
A Blu-ray Disc-ROM (BD-ROM)
capacity of 100 GB
has a storage
DVD-RW, DVD+RW, and DVD+RAM are high-
capacity rewritable DVD formats
15
11

Flash Memory Storage
•
Flash memory chips are a type of solid state
media and contain no moving parts
Examples of flash
» Solid state drives
» Memory card
memory storage are:–
» USB flash drives
16
12

Solid State
Drives
•
Solid state drives (SSDs) have several
over magnetic hard disks:
advantages
Generate less heat and
consume less powerFaster access time Faster transfer rates Last longer
17
13

Memory card
•
A memory card is a removable flash memory
device that you insert and remove from a slot in a
computer,mobile device, or card reader/writer
Secure Digital
High Capacity
(SDHC)
CompactFlash
(CF)
Secure Digital
(SD) microSD
xD Picture
Card
Memory Stick
Micro (M2)microSDHC Memory Stick
19
15

USB flash drives
•
USB flash
computer
drives plug into a USB port on a
or mobile device
Page 367
Figure 7-21
21
17

Storage Capacity Differences table:
( between magnetic, optical and flash memory )
22
Types of Storage Media Examples Storage capacities
Magnetic disk External hard disks 2 TB or more
Internal hard disks 160 GB to 2TB
Removable hard disks 1 TB or more
Optical Disc DVD (1 Side-1 Layer) 4.7 GB
DVD (1 Side – 2 Layers) 8.5 GB
DVD (2 Sides-1 Layer) 9.4 GB
DVD (2 Sides-2 Layers) 17 GB
Blu-ray Disc (1 Side-1 Layer) 25 GB
Blu-ray Disc (1 Side-2 Layers) 50 GB
Blu-ray Disc (2 Sides-1 Layer) 50 GB
Blu-ray Disc (2 Sides-2 Layers) 100 GB
CD-ROM 650 MB to 1 GB
18

23
Typical of Flash Memory Storage
Storage Capacities
Solid State Drives(SSD) 16GB – 256GB
Memory cards
Compact Flash(CF)
Secure Digital(SD)
SDHC
XD Picture Card
512MB – 100GB
512MB – 8GB
4GB – 32GB
256MB – 2GB
USB Flash Drive 512MB – 100GB
19

Compare Memory and Storage
24
Memory (RAM) Storage
Hold data temporarily. Hold data permanently.
Hold programmable data , instruction and
processing data.
Hold data and information when they are not
being processed.
Memory are located on the motherboard. Storage are located outside the motherboard.
Data in the memory will be lost when the
power is turn off.
Data in the storage will not be lost when the
power is turn off.
20

PST SC015 Chapter 2 Computer System (II) 2017/2018

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