This document provides an overview of computer systems and their components. It discusses that a computer system includes hardware, software, data, and users. The central processing unit (CPU) processes data and controls other computer parts. Data is represented using binary digits (bits) and bytes. Computers are used for information systems, personal computing, science/research, process control, education, and entertainment. Computer shapes include supercomputers, mainframes, minicomputers, workstations, and microcomputers. Input devices allow data to enter the system while output devices display processed data.

1. COMPUTER SYSTEM
1

2. What is Computer?
Computer
- an electronic device capable of interpreting and
executing programmed commands. It includes both
hardware (physical equipment) and software
( instructions that tell the hardware what to do)
Computer System – a collection of interrelated devices
that work together to transform data into
information.
Data – characters, symbol, or other raw,
2
unrecognized material.
Information – data organized into useful,
meaningful form

3. 3
Four Basic Functions
 Input – gathering data and
communicating the data to the computer
Processing – transforming data into
meaningful for by performing various
operations.
Output – display the data once it has been
processed
Storage – storing the result of processing
so that they can be used at a later time

4. 4

5. The Central Processing Unit (CPU)
- the part of the computer that processes
data and controls the other parts of the
computer system
5
Two (2) basic Parts
1. Arithmetic Logic unit – processes data
by manipulating numbers, letters,
and symbols.
2. Control Unit – coordinates and controls
the other parts of the computer
system

6. 6

7. 7

8. 8

9. How computer represents and
9
stores data?
Binary system – a system that uses just
two symbols to represent all
information
Bit – a zero or one
Bytes – a string of 8-bits, typically
representing one character of
information

10. How do we use Computers?
1. Information system/data processing
– computer-based information that
provides organization with data processing
capabilities and the knowledge workers in
the organization with the information they
need to make a better informed decisions.
- combined hardware, software, people,
procedures, and data.
10

11. How do we use Computers?
2. Personal Computing
- the single-user micro used for a
variety of business and domestic
such as
11
 Word processing
 Desktop publishing
 Spreadsheet software
 Database software
 Graphic software

12. How do we use Computers?
2. Science, research, and engineering
- the computer is used as a tool in
experimentation, design and development.
12
3. Process/ Device Control
- applications that involve process.
4. Education
- the computer interacts with a student to
enhance the learning process

13. How do we use Computers?
13
5. Computer-Aided Design (CAD)
– using the computer in the design process.
6. Entertainment
- computer applications are being designed and
created just to entertain us.
7. Artificial intelligence
- creating computer system with the ability to
reason, learn, or to accumulate knowledge, to
strive for self-improvement, and to stimulate
human- sensory and mechanical capabilities.

14. 14
SHAPES OF COMPUTERS
• Supercomputers
• Mainframe Computers
• Minicomputers
• Workstations
• Microcomputers, or Personal Computers

15. 15
Supercomputers
•Supercomputers are the
most powerful computers.
They are used for problems
requiring complex
calculations.
•Because of their size and
expense, supercomputers
are relatively rare.
•Supercomputers are used by
universities, government
agencies, and large
businesses.

16. 16

17. 17
Mainframe Computers
• Mainframe computers can support hundreds or
thousands of users, handling massive amounts
of input, output, and storage.
• Mainframe computers are used in large
organizations where many users need access
to shared data and programs.
• Mainframes are also used as e-commerce
servers, handling transactions over the
Internet.

18. 18

19. 19
Minicomputers
• Minicomputers are smaller than mainframes
but larger than microcomputers.
• Minicomputers usually have multiple
terminals.
• Minicomputers may be used as network
servers and Internet servers.

20. 20

21. Workstations
• Workstations are powerful single-user
21
computers.
• Workstations are used for tasks that require a
great deal of number-crunching power, such as
product design and computer animation.
• Workstations are often used as network and
Internet servers.

22. 22

23. Microcomputers, or Personal Computers
• Microcomputers are more commonly known as
personal computers. The term "PC" is applied to
IBM-PCs or compatible computers.
• Full-size desktop computers are the most
23
common type of PC.
• Notebook (laptop) computers are used by people
who need the power of a desktop system, but
also portability.
• Handheld PCs (such as PDAs) lack the power of
a desktop or notebook PC, but offer features for
users who need limited functions and small size.

24. 24

25. 25

26. 26

27. 27

28. 28

29. 29

30. 30

31. 31

32. 32

33. Using Computers - in the home
33
 This refrigerator
allows customers -
from their kitchens -
to access selected
retailers, order, scan
and purchase goods,
pay their bills, even
watch television and
send e-mail
messages

34. 34
 A computer is a tool
 A computer is not
intelligent
 Everything it does
come from instructions
it receives from a
person.

35. 35

36. What is Computer?
A complete computer system includes four distinct
36
parts:
Hardware
Software
Data
User

37. computer system
37

38. 38
Hardware
• A computer's hardware consists of electronic
devices; the parts you can see and touch.
• The term "device" refers to any piece of
hardware used by the computer, such as a
keyboard, monitor, modem, mouse, etc.

39. A computer's hardware devices are categorized
as follows:
• Processor
• Memory
• Input and output (I/O) devices
• Storage devices
• Communication devices
39
Types of Hardware

40. 40

41. Primary Memory and Processor
- stores data temporarily and works
closely with the CPU.
41
RAM
Chip Processor

42. 42
Input Device
A device which takes in data
and program instructions and
converts them into digital form

43. 43
 keypad at a bank machine

44. The Keyboard - Standard Keyboard Layout
• A standard computer keyboard has about 100
keys.
• Most keyboards use the QWERTY layout, named
for the first six keys in the top row of letters.
44

45. The Keyboard - Standard Keyboard Layout
Most keyboards have keys arranged in five
groups:
45
1. Alphanumeric keys
2. Numeric keypad
3. Function keys
4. Modifier keys
5. Cursor-movement keys

46. 46
ACADEMIC RECORDS
Password
* * * * *
ENTER Invalid Password

47. The Keyboard - Ergonomic Keyboards
• Long periods of keyboard use can cause
injuries.
• An ergonomically correct keyboard can help
you avoid injuries.
• You also can avoid injuries by adopting correct
keyboarding practices.
47

48. 48

49. The Keyboard - How a Keyboard Works
• The keyboard controller detects the keystroke.
• The controller places a scan code in the
keyboard buffer, indicating which key was
pressed.
• The keyboard sends the computer an interrupt
request, telling the CPU to accept the keystroke.
49
When you press a key:

50. 50

51. 51
Pointing Devices
The Mouse
• What is a Mouse?
• Mouse
Techniques

52. The Mouse - What is a Mouse?
• The mouse is a pointing device. You use it
to move a graphical pointer on the screen.
• The mouse can be used to issue commands,
draw, and perform other types of input
tasks.
52

53. Using the mouse involves five techniques:
53
The Mouse - Mouse Techniques
1. Pointing; Move the mouse to move the on-screen
pointer.
2. Clicking; Press and release the left mouse button
once.
3. Double-clicking; Press and release the left mouse
button twice.
4. Dragging; Hold down the left mouse button as you
move the pointer.
5. Right-clicking; Press and release the right mouse
button.

54. 54
Variants of the Mouse
• Trackballs
• Trackpads
• Integrated Pointed Devices

55. Trackballs
• A trackball is like a mouse turned upside-down.
• Use your thumb to move the exposed ball and
your fingers to press the buttons.
55
Many styles
of trackball
are available.

56. Trackpads
• A trackpad is a touch-sensitive pad that
provides the same functionality as a mouse.
• To use a trackpad, you glide your finger across
56
its surface.
• Trackpads provide a set of buttons that
function like mouse buttons.

57. 57

58. 58
Integrated Pointing Devices
• An integrated pointing device is a small joystick
built into the keyboard.
• To use an integrated pointing device, you move
the joystick.
• These devices provide a set of buttons that
function like mouse buttons

59. 59

60. Alternative Input Devices –
Devices for the Hand
60
• Pens
• Touch Screens
• Game Controllers

61. 61
Pens
• With a pen-based system, you
use an electronic pen to write
on the screen and choose
commands.
• Pens are common input devices
for handheld computers, like “personal digital
assistants (PDAs).”
• Pens are handy for making notes or selecting
commands, not for inputting a lot of text.

62. 62
The user can point, tap,
draw and write on the
computer’s screen with a
pen.

63. Touch Screens
• Touch-screen systems accept input directly
through the monitor.
• Touch screens use sensors to detect the touch
of a finger. They are useful where
environmental conditions prohibit the use of a
keyboard or mouse.
• Touch-screen systems are useful for selecting
options from menus.
63

64. 64

65. Game Controllers
• The two primary types of game controllers are
joysticks and game pads.
• Game pads usually provide controls for each
hand.
• Joysticks are popular for flight simulator and
driving games.
65

66. Joystick
Game pad
66

67. Alternative Input Devices –
Optical Input Devices
67
• Bar Code Readers
• Image Scanners and OCR

68. Bar Code Readers
• Bar code readers can read bar codes—patterns
68
of printed bars.
• The reader emits light, which reflects off the bar
code and into a detector in the reader. The
detector translates the code into numbers.
• Flatbed bar code readers are commonly found in
supermarkets. Courier services often use
handheld readers.

69. 69
Bar code readers
commonly track
sales in retail stores

70. Image Scanners and OCR
• Image scanners digitize printed images for
storage and manipulation in a computer.
• A scanner shines light onto the image and
70
interprets the reflection.
• Optical character recognition (OCR) software
translates scanned text into editable electronic
documents.

71. Hand-held scanner – read data on
price tags, shipping labels, inventory
part numbers, book ISBN and the like.
Sometimes called “wand scanner”
71
Bar code

72. Stationary label scanner – rely exclusively
on laser technology and are used in the
same type of application as wand
scanners.
72

73.  Page scanners – used to translate printed hard
copy to machine-readable format.
73

74. Document scanner – capable of scanning
documents of various sizes ( utility bill
invoice stubs and sales slips from credit
card transactions)
74

75. Continuous-form scanner – read data
printed on continuous forms such as cash
register tapes.
75

76. Optical mark scanner – can preprinted
forms, such as multiple-choice test answer
forms.
76

77. 77
Other Scanners
Retinal/Iris Scanner

78. 78
Other Scanners
Signature Scanner

79. 79
Other Scanners
Fingerprint Scanner

80. 80
Other Scanners
Fingerprint Scanner
Door Lock
Time Attendance

81. Alternative Input Devices –
Audio-Visual (Multimedia) Input Devices
• Microphones and Speech Recognition
• Video Input
81

82. Audio-Visual (Multimedia) Input Devices -
Microphones and Speech Recognition
• Microphones can accept auditory input. A
microphone requires a sound card in the PC.
• A sound card can digitize analog sound
signals, and convert digital sound signals to
analog form.
• With speech recognition software, you can use
your microphone to dictate text, navigate
programs, and choose commands.
82

83. 83
Microphones
Sound Card

84. Audio-Visual (Multimedia) Input Devices –
84
Video Input
• PC video cameras digitize full-motion images.
• Digital cameras capture still images.
• These cameras break images into pixels and
store data about each pixel.
• Video images may be compressed to use less
memory and storage space.

85. 85

86. 86
Digital Cameras
Camcorder

87. Input Devices Summary
87
 Keyboard
 Mouse
Variants of Mouse
Trackballs
Track pad
 Integrated Pointing Device

88. 88
 Alternate Input Device
Hand Devices
 Pen
 Touch Screen
 Game Controllers
Joystick
Game pad

89. 89
 Optical Input Devices
 Bar Code
 Image Scanners and OCR
Hand-held scanner
Page scanner
Document scanner
Continuous scanner
Optical Mark scanner
Iris/Retina scanner
Signature scanner
Finger print scanner
Palm scanner

90. 90
 Audio-Visual Input Devices
Microphones and Speech Recognition
Video Input

91. Output Device
A device that allows a
computer to communicate with
the user by displaying
processed data in a way the
user can understand and use.
91

92. The Monitors
- a television – like display for softcopy output in a
92
computer system
Categories of Monitors
Monitors are categorized by the technology they
use:
• Cathode ray tube (CRT) monitors
• Flat-panel displays
And by the way they display colors:
• Monochrome – One color on a black
background
• Grayscale – Shades of gray on a white or off-white
background
• Color – From 16 to 16 million unique colors

93. 93
Monochrome
Grayscale
Colored

94. Monitors - CRT Monitors
• In CRT monitors, electrons are fired at phosphor
94
dots on the screen.
• The dots are grouped into pixels, which glow
when struck by electrons.
• In color CRTs, each pixel contains a red, green,
and blue dot. These glow at varying intensities
to produce color images.

95. 95

96. Monitors - Flat-Panel Monitors
• Most flat-panel monitors use liquid crystal
96
display (LCD) technology.
• Passive matrix LCD uses a transistor for each
row and column of pixels.
• Active matrix LCD uses a transistor for each
pixel on the screen.
• Thin-film transistor displays use multiple
transistors for each pixel.

97. Flat-panel monitors take up less desk space.
97

98. 98
DTV – Digital Television
 A digital signal transmits the information for
video and sound as ones and zeros instead
of as a wave.
 DTV usually uses MPEG-2 encoding, the
industry standard for most DVDs, to
compress the signal to a reasonable size.

99.  The picture, even when displayed on a small TV, is better
quality.
 A digital signal can support a higher resolution, so the
picture will still look good when shown on a larger TV
screen.
 The video can be progressive rather than interlaced - the
screen shows the entire picture for every frame instead of
every other line of pixels.
 TV stations can broadcast several signals using the same
bandwidth. This is called multicasting.
 If broadcasters choose to, they can include interactive
content or additional information with the DTV signal.
 It can support high-definition (HDTV) broadcasts.
99
DTV has several advantages:

100.  part of the DTV transition
 The highest HDTV resolution is 1920 x 1080
pixels. HDTV can display about ten times as
many pixels as an analog TV set.
100
HDTV – High Definition TV
HDTV requires three parts:
 A source, such as a local, cable or satellite
HDTV station
 A way to receive the signal, like an antenna,
cable or satellite service
 An HDTV set

101. HDTVs don't have to be enormous. This
26-inch set is HDTV ready.
101

102. If you purchase an HDTV-ready set, you'll need a
receiver before you can watch high-definition
102
broadcasts.

103.  EDTV isn't one of the digital broadcast formats -
it's a description of the level of picture quality the
set can produce. An EDTV set can produce better
quality than SDTV, but it's not an HDTV set. Most
EDTV sets are flat-panel LCD or plasma sets.
103
EDTV – Enhanced Definition TV

104. 104
PC Projectors
• A PC projector connects to a PC and is used to
project images on a large screen.
• Many PC projectors provide the same
resolutions and color levels as high-quality
monitors.
• Digital light processing (DLP) projectors use a
microchip containing tiny mirrors to produce
very sharp, bright images.

105. 105

106. 106
Projected
Screen

107. 107
The Printers
Printers fall into two categories:
• Impact printers use a device to strike an inked
ribbon, pressing ink from the ribbon onto the
paper.
• Non-impact printers use different methods to
place ink (or another substance) on the page.

108. Evaluating Printers
When evaluating printers, consider four criteria:
• Image quality – Measured in dots per inch (dpi).
Most printers produce 300 – 600 dpi.
• Speed – Measured in pages per minute (ppm) or
108
characters per second (cps).
• Initial cost – Consumer printers cost $250 or
less, but professional printers can cost
thousands of dollars.
• Cost of operation – This refers to the cost of
supplies used by the printer.

109. 109
Dot Matrix Printers
• How Do Dot Matrix Printers Work?
• Performance

110. Dot Matrix Printers -
How Do Dot Matrix Printers Work?
• Dot matrix printers are a common type of
110
impact printer.
• A dot matrix printer's print head contains a
cluster of pins. The printer can push the pins
out to form patterns in rapid sequence.
• The pins press an inked ribbon against the
paper, creating an image.

111. 111

112. Dot Matrix Printers - Performance
• Lower-resolution dot matrix printers use nine
pins. Higher-resolution models have 24 pins.
• Speed is measured in characters per second
(cps). Some dot matrix printers print 500 cps.
112

113. 113
Ink Jet Printers
• How Do Ink Jet Printers Work?
• Performance

114. 114
Ink Jet Printers –
How Do Ink Jet Printers Work?
• Ink jet printers are an example of non-impact
printers.
• The printer sprays tiny droplets of ink onto the
paper.
• Ink jet printers are available for color and black-and-
white printing.

115. 115

116. Ink Jet Printers - Performance
• Ink jet printers offer speeds of (2 – 4 pages
per minute ppm) and resolution (300 – 600
dots per inch dpi), comparable to low-end
laser printers.
• Ink jet printers are inexpensive and have low
operating costs.
116

117. 117
Laser Printers
• How Do Laser Printers Work?
• Performance

118. 118

119. 119
Laser Printers –
How Do Laser Printers Work?
• Laser printers are non-impact printers.
• They use heat and pressure to bond particles
of toner to paper.
• Laser printers are available for color and
black-and-white printing.

120. 120

121. Laser Printers - Performance
• Laser printers provide resolutions from 300 –
1200 dpi and higher.
• Black-and-white laser printers usually
produce 4 – 16 ppm.
• Laser printers produce higher-quality print
than ink jet printers, but are more expensive.
121

122. 122
Snapshot Printers
•Snapshot printers are
specialized, small-format
printers that print
digital photographs.
•Snapshot printers are
fairly slow, and can be
more expensive to
operate

123. Snapshot printers are popular among
123
digital camera users

124. Other High-Quality Printers
Print shops and publishers use these printers to
create high-quality color images:
124
Fiery

125. 125
Other High-Quality Printers
Thermal-wax printer Thermal-wax ribbons

126. 126
Other High-Quality Printers
Dye Sublimation

127. 127
Other High-Quality Printers
IRIS Printers

128. 128
Other High-Quality Printers
Plotters

129. Plotters use mechanical, ink jet, or thermal
technology to create large-format images for
architectural or engineering uses.
129

130. Output Devices Summary
130
 Monitor
Use
 CRT
 Flat-panel
Color
 Monochrome
 Grayscale
 Colored
 PC Projector

131. 131
 Printer
Categories
 Impact
Type Writer
Dot Matrix
Non-Impact
Laser
Inkjet
Thermal Wax
Other High Quality Printers

132. Storage Devices
A device from which the computer
reads data, and to which the
computer writes data.
132

133. Storage Devices Summary
133
 Magnetic Devices
Floppy Disk
Hard Disk
Magnetic Tape
Disk Cartriages

134. 134
 Optical Storage Devices
Compact Disk Read-Only Memory (CD-ROM)
Digital Video Disk Read-Only Memory (DVD-ROM)
CD-Recordable (CD-R)
CD-Rewritable (CD-RW)
PhotoCD

135.  Other Removable Storage Devices
135
USB Flash Drive
Compact Flash
Memory Stick
Smart Media

136. 136
Categorizing Storage Devices
• The physical material that actually holds data is
called a storage medium. The surface of a floppy
disk is a storage medium.
• The hardware that writes data to or reads data
from a storage medium is called a storage
device. A floppy disk drive is a storage device.
• The two primary storage technologies are
magnetic and optical.

137. 137
Magnetic Storage Devices
• Diskettes
• Hard Disks
• Other Magnetic Storage Devices

138. 138
Early Storage Device
some early computers used paper punch
cards to store information

139. 139
Magnetic Storage Devices
• A magnetic disk's medium contains iron
particles, which can be polarized—given a
magnetic charge—in one of two directions.
• Each particle's direction represents a 1 (on) or 0
(off), representing each bit of data that the CPU
can recognize.
• A disk drive uses read/write heads containing
electromagnets to create magnetic charges on
the medium.

140. 140
Random particles
(no data stored)
Current flow
(write operation)
Organized particles
(represent data)
Medium
Write head

141. 141
As the medium
rotates, the head
writes the data.

142. Magnetic Storage Devices - Formatting
• Before a magnetic disk can be used, it must be
formatted—a process that maps the disk's
surface and determines how data will be stored.
• During formatting, the drive creates circular
tracks around the disk's surface, then divides
each track into sectors.
• The OS organizes sectors into groups, called
clusters, then tracks each file's location
according to the clusters it occupies.
142

143. 143
Formatted Disk

144. Magnetic Storage Devices - Disk Areas
When a disk is formatted, the OS creates four
areas on its surface:
• Boot sector – stores the master boot record, a
small program that runs when you first start (boot)
the computer
• File allocation table (FAT) – a log that records
each file's location and each sector's status
• Root folder – enables the user to store data on
144
the disk in a logical way
• Data area – the portion of the disk that actually
holds data

145. 145

146. Diskettes
• Diskette drives, also known as floppy disk
drives, read and write to diskettes (called floppy
disks or floppies).
• Diskettes are used to transfer files between
computers, as a means for distributing
software, and as a backup medium.
• Diskettes come in two sizes: 5.25-inch and 3.5-
146
inch.

147. 3.5-inch 5.25-inch
147

148. 3.5 inch
floppy
and drive
148

149. 149
Floppy Disk Drive

150. Hard Disks
• Hard disks use multiple platters, stacked on a
spindle. Each platter has two read/write heads,
one for each side.
• Hard disks use higher-quality media and a
faster rotational speed than diskettes.
150

151. Read/write heads
151

152. Removable hard disks combine high capacity
with the convenience of diskettes.
152

153. Disk Capacities
• Diskettes are available in different capacities,
but the most common store 1.44 MB.
• Hard disks store large amounts of data. New
PCs feature hard disks with capacities of 10
GB and higher.
153

154. 154
Other Magnetic Storage Devices
• High-capacity floppy disks offer capacities up
to 250 MB and the portability of standard floppy
disks.
• Disk cartridges are like small removable hard
disks, and can store up to 2 GB.
• Magnetic tape systems offer very slow data
access, but provide large capacities and low
cost.

155. 155
Magnetic Tape

156. Due to long access times, tape
drives are used mainly for backups.
156

157. The primary types of optical storage are:
157
• CD•
CD-Recordable (CD-R)
• CD-Rewritable (CD-RW)
• DVD
• CD-Recordable (CD-R)
• CD-Rewritable (CD-RW)
• PhotoCD
• Blu-ray Disc (BD)

158. 158
How Optical Storage Works
• An optical disk is a high-capacity storage
medium. An optical drive uses reflected light to
read data.
• To store data, the disk's metal surface is
covered with tiny dents (pits) and flat spots
(lands), which cause light to be reflected
differently.
• When an optical drive shines light into a pit, the
light cannot be reflected back. This represents
a bit value of 0 (off). A land reflects light back to
its source, representing a bit value of 1 (on).

159. 159
1 0

160. 160
CD-ROM
• In PCs, the most commonly used
optical storage technology is called
Compact Disk Read-Only Memory (CD-ROM).
• A standard CD-ROM disk can store up to 650 MB
of data, or about 70 minutes of audio.
• Once data is written to a standard CD-ROM disk,
the data cannot be altered or overwritten.

161. 161
CD-ROM Speeds and Uses
• Early CD-ROM drives were called single speed,
and read data at a rate of 150 KBps. (Hard disks
transfer data at rates of 5 – 15 MBps).
• CD-ROM drives now can transfer data at speeds
of up to 7800 KBps. Data transfer speeds are
getting faster.
• CD-ROM is typically used to store software
programs. CDs can store audio and video data,
as well as text and program instructions.

162. DVD-ROM
• A variation of CD-ROM is called Digital Video
Disk Read-Only Memory (DVD-ROM), and is
being used in place of CD-ROM in many newer
PCs.
• Standard DVD disks store up to 9.4 GB of data
—enough to store an entire movie. Dual-layer
DVD disks can store up to 17 GB.
• DVD disks can store so much data because
both sides of the disk are used, along with
sophisticated data compression technologies.
162

163. 163

164. 164
Other Optical Storage Devices
• A CD-Recordable (CD-R) drive lets you record
your own CDs, but data cannot be overwritten
once it is recorded to the disk.
• A CD-Rewritable (CD-RW) drive lets you record a
CD, then write new data over the already
recorded data.
• PhotoCD technology is used to store digital
photographs.

165. 165

166. 166
BLU-RAY DISC
 The new format offers an immense storage capacity
(up to 50GB) that is perfect for High Definition video
recording and distribution, as well as for storing
large amounts of data.
 A single-layer Blu-ray disc, which is roughly the
same size as a DVD, can hold up to 27 GB of data --
that's more than two hours of high-definition video
or about 13 hours of standard video.
 A double-layer Blu-ray disc can store up to 54 GB,
enough to hold about 4.5 hours of high-definition
video or more than 20 hours of standard video.

167. Photo courtesy Blu-ray Disc Association
167

168. Other Removable Storage Devices
168

169. Memory stick, Flash Memory, Compact Flash,
Smart Media, Secure Digital, Micro Drive.
169

170. 170
Smart Media Card
A removable flash
memory card that can be
used in several different
types of digital devices;
including digital cameras,
digital music players and
digital voice recorders.

171. 171
Memory Stick

172. 172
The Pen Drive, USB Flash Drive
 Pluggable, portable and powerful, USB flash
drives, sometimes we call them JumpDrives,
Pocket drives, Pen drives, or Thumb drives,
are always the best digital storage solution.
All USB flash drives pretty much operate the
same way. USB flash drives may have
different design, different capacity and
different price – and some USB flash drives
feature add-on functions such as MP3
players – but they do share some other
characteristics:

173.  With proper use, an USB flash drive can last
more than 10 years.
173

174. Other Removable Storage Devices
174
Secure Digital
Compact flash

175. Other Removable Storage Devices
175
Iomega Peerless
Zip Drive

176. Communication Devices
Perform both input and output,
allowing computers to share
176
information.

177. Modem
 The word "modem" is a contraction of the words
modulator-demodulator. A modem is typically
used to send digital data over a phone line.
 The sending modem modulates the data into a
signal that is compatible with the phone line, and
the receiving modem demodulates the signal
back into digital data. Wireless modems
convert digital data into radio signals and back.
177

178. Modem converts digital signals into analog signals
so that the data can be transmitted over the
telephone lines
* Telephone lines were designated for voice communication,
not data communication
178

179. 179
56k Internal Modem
External Modem

180. Headset
Headset consists of a receiver (speaker) that lets
you hear the person at the other end of the
conversation, and a transmitter (microphone) that
converts your voice into electrical impulses to be
transmitted to the other person.
In a headset, these two components are usually
supported by a headband over your head) or an
earhook (over your ear), or something in your ear
like a hearing aid or a stethoscope. Most modern
headsets are comfortable for people who wear
eyeglasses.
180

181.  A good headset can give you extremely good
sound for games, movies and music without
disturbing others; and the microphone works
great for speech recognition programs and
internet phone calls
 If you travel with a laptop computer, a headset
can provide much better sound than the tiny
built-in speakers; and it's much easier to pack a
headset than to stuff speakers into your
computer case.
181

182. 182

183. Network Interface Card (NIC)
NIC facilitates and controls the exchange of data
between/among the micros in a network.
183

184. WebCam
 A simple Webcam consists of a digital
camera attached to your computer. They are
easy to connect through a USB port (earlier
cameras connected through a dedicated card
or the parallel port).
184

185. 185
 In order for you to create
a simple Webcam, you
need three things:
 A camera of some sort
connected to your
computer
 A piece of software that
can grab a frame from the
camera periodically
 A relatively consistent
connection between your
computer and the Internet.

186. 186
Software
A set of electronic instructions that tells the
computer how to do certain tasks. A set of
instructions is often called a program.

187. The Parts of a Computer System - Software
• When a computer is using a particular
program, it is said to be running or
executing the program.
• The two most common types of programs
are system software and application
software.
187

188. • Software – also called programs – consists
of organized sets of instructions for
controlling the computer.
• Some programs exist for the computer's
use, to help it manage its own tasks and
devices.
• Other programs exist for the user, and
enable the computer to perform tasks for
you, such as creating documents.
188

189. 189

190. TWO BASIC TYPES OF SOFTWARE
System Software
• System software exists primarily for the
computer itself, to help the computer perform
specific functions.
• One major type of system software is the
operating system (OS). All computers require
an operating system.
• The OS tells the computer how to interact with
190
the user and its own devices.
• Common operating systems include Windows,
the Macintosh OS, OS/2, and UNIX .

191. Applications Software
• Application software tells the computer how to
accomplish tasks the user requires, such as
creating a document or editing a graphic image.
• Some important kinds of application software
191
are:
Word processing programs Spreadsheet software
Database management Presentation programs
Graphics programs Networking software
Web design tools and browsers Internet applications
Communications programs Utilities
Entertainment and education Multimedia authoring

192. 192
Data
Consists of raw facts, which the computer can
manipulate and process into information that is
useful to people.

193. The Parts of a Computer System - Data
• Computerized data is digital, meaning that
it has been reduced to digits, or numbers.
The computer stores and reads all data as
numbers.
• Although computers use data in digital
form, they convert data into forms that
people can understand, such as text,
numerals, sounds, and images.
193

194. Ten different
symbols in
the decimal
system
Numbers above 9
use more than 1 digit
194

195. 195
Users
People are the computer's
operators, or users.

196. The Parts of a Computer System – Users
• Some types of computers can operate
without much intervention from people, but
personal computers are designed
specifically for use by people.
196