EE120 Information Technology 1

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SRI LANKA INSTITUTE of ADVANCED TECHNOLOGICAL
EDUCATION

Electrical and Electronic
Engineering
Instructor Manual
Training
Unit

Training Unit

Information Technology 1
Theory

No: EE 120

Training Unit
Information Technology 1
Theoretical Part
No.: EE 120

Edition:

2009
All Rights Reserved

Editor:

MCE Industrietechnik Linz GmbH & Co
Education and Training Systems, DM-1
Lunzerstrasse 64 P.O.Box 36, A 4031 Linz / Austria
Tel. (+ 43 / 732) 6987 – 3475
Fax (+ 43 / 732) 6980 – 4271
Website: www.mcelinz.com

2

Information Technology
LIST OF CONTENT

1

2

Introduction to Information Technology .................................................................. 5
1.1

History of Information Technology.................................................................. 5

1.2

Information Technology's Role Today ............................................................ 6

1.3

Computers in Business .................................................................................. 7

1.4

Computers in Medicine................................................................................... 7

1.5

Computers in Science and Engineering ......................................................... 7

1.6

Integrated Information Systems ..................................................................... 8

1.7

Software ......................................................................................................... 8

1.8

Productivity Software...................................................................................... 9

1.9

Hardware...................................................................................................... 10

1.10

Information and Data Processing ................................................................. 11

User – Interface .................................................................................................... 12
2.1

Input Devices................................................................................................ 12

2.1.1

Keyboard .................................................................................................. 12

2.1.2

Pointing Devises....................................................................................... 15

2.1.3

Source Data-Entry Devices ...................................................................... 17

2.1.4

Audio Input Devices ................................................................................. 22

2.1.5

Video Input Devices ................................................................................. 25

2.2

Output Devices............................................................................................. 28

2.2.1

Display Screens ....................................................................................... 28

2.2.2

Printers ..................................................................................................... 33

All-In-One Printer Considerations ......................................................................... 34
Inkjet Printers:....................................................................................................... 34
2.2.3
2.3
3

Audio-output devices................................................................................ 38
Ergonomics .................................................................................................. 43

Database Systems................................................................................................ 50
3.1

Database Management Systems ................................................................. 51

3

4

3.2

Hierarchical Database .................................................................................. 52

3.3

Network Database........................................................................................ 55

3.4

Relational Database ..................................................................................... 56

3.5

Object Oriented Database............................................................................ 60

System Software................................................................................................... 64
4.1

The Operating System ................................................................................. 64

4.2

CPU Management........................................................................................ 73

4.3

File Management.......................................................................................... 77

4.4

Spatial file manager...................................................................................... 82

4.5

Task Management........................................................................................ 83

4.6

Network Operating Systems......................................................................... 87

4.7

Protecting Data on a Network ...................................................................... 91

4

1

Introduction to Information Technology

Information technology is "the study, design, development, implementation, support or
management

of

computer-based

information

systems,

particularly

software

applications and computer hardware." Encompassing the computer and information
systems industries, information technology is the capability to electronically input,
process, store, output, transmit, and receive data and information, including text,
graphics, sound, and video, as well as the ability to control machines of all kinds
electronically.

Information technology is comprised of computers, networks, satellite communications,
robotics, videotext, cable television, electronic mail ("e-mail"), electronic games, and
automated office equipment. The information industry consists of all computer,
communications, and electronics-related organizations, including hardware, software,
and services. Completing tasks, using information technology, results in rapid
processing and information mobility, as well as improved reliability and integrity of
processed information.

1.1

History of Information Technology

The term "information technology" evolved in the 1970s. Its basic concept, however,
can be traced to the World War II alliance of the military and industry in the
development of electronics, computers, and information theory. After the 1940s, the
military remained the major source of research and development funding for the
expansion of automation to replace manpower with machine power.
Since the 1950s, four generations of computers have evolved. Each generation
reflected a change to hardware of decreased size but increased capabilities to control
computer operations. The first generation used vacuum tubes, the second used
transistors, the third used integrated circuits, and the fourth used integrated circuits on
a single computer chip. Advances in artificial intelligence that will minimize the need for
complex programming characterize the fifth generation of computers, still in the
experimental stage.

5

The first commercial computer was the UNIVAC I, developed by John Eckert and John
W. Mauchly in 1951. It was used by the Census Bureau to predict the outcome of the
1952 presidential election. For the next twenty-five years, mainframe computers were
used in large corporations to do calculations and manipulate large amounts of
information stored in databases. Supercomputers were used in science and
engineering, for designing aircraft and nuclear reactors, and for predicting worldwide
weather patterns. Minicomputers came on to the scene in the early 1980s in small
businesses, manufacturing plants, and factories.

In 1975, the Massachusetts Institute of Technology developed microcomputers. In
1976, Tandy Corporation's first Radio Shack microcomputer followed; the Apple
microcomputer was introduced in 1977. The market for microcomputers increased
dramatically when IBM introduced the first personal computer in the fall of 1981.
Because of dramatic improvements in computer components and manufacturing,
personal computers today do more than the largest computers of the mid-1960s at
about a thousandth of the cost.

Computers today are divided into four categories by size, cost, and processing ability.
They are supercomputer, mainframe, minicomputer, and microcomputer, more
commonly known as a personal computer. Personal computer categories include
desktop, network, laptop, and handheld.

1.2

Information Technology's Role Today

Every day, people use computers in new ways. Computers are increasingly affordable;
they continue to be more powerful as information-processing tools as well as easier to
use.

6

1.3

Computers in Business

One of the first and largest applications of computers is keeping and managing
business and financial records. Most large companies keep the employment records of
all their workers in large databases that are managed by computer programs. Similar
programs and databases are used in such business functions as billing customers;
tracking payments received and payments to be made; and tracking supplies needed
and items produced, stored, shipped, and sold. In fact, practically all the information
companies need to do business involves the use of computers and information
technology.
On a smaller scale, many businesses have replaced cash registers with point-of-sale
(POS) terminals. These POS terminals not only print a sales receipt for the customer
but also send information to a computer database when each item is sold to maintain
an inventory of items on hand and items to be ordered. Computers have also become
very important in modern factories. Computer-controlled robots now do tasks that are
hot, heavy, or hazardous. Robots are also used to do routine, repetitive tasks in which
boredom or fatigue can lead to poor quality work.

1.4

Computers in Medicine

Information technology plays an important role in medicine. For example, a scanner
takes a series of pictures of the body by means of computerized axial tomography
(CAT) or magnetic resonance imaging (MRI). A computer then combines the pictures
to produce detailed three-dimensional images of the body's organs. In addition, the
MRI produces images that show changes in body chemistry and blood flow.

1.5

Computers in Science and Engineering

Using supercomputers, meteorologists predict future weather by using a combination
of observations of weather conditions from many sources, a mathematical
representation of the behavior of the atmosphere, and geographic data.

7

Computer-aided design and computer-aided manufacturing programs, often called
CAD/CAM, have led to improved products in many fields, especially where designs
tend to be very detailed. Computer programs make it possible for engineers to analyze
designs of complex structures such as power plants and space stations.

1.6

Integrated Information Systems

With today's sophisticated hardware, software, and communications technologies, it is
often difficult to classify a system as belonging uniquely to one specific application
program. Organizations increasingly are consolidating their information needs into a
single, integrated information system. One example is SAP, a German software
package that runs on mainframe computers and provides an enterprise-wide solution
for information technologies. It is a powerful database that enables companies to
organize all their data into a single database, then choose only the program modules
or tables they want. The freestanding modules are customized to fit each customer's
needs.

1.7

Software

Computer software consists of the programs, or lists of instructions, that control the
operation of a computer. Application software can be used for the following purposes:


As a productivity/business tool



To assist with graphics and multimedia projects



To support household activities, for personal business, or for education



To facilitate communications

8

1.8

Productivity Software

Productivity software is designed to make people more effective and efficient when
performing daily activities. It includes applications such as word processing,
spreadsheets, databases, presentation graphics, personal information management,
graphics and multimedia, communications, and other related types of software. Wordprocessing software is used to create documents such as letters, memos, reports,
mailing labels, and newsletters. This software is used to create attractive and
professional-looking documents that are stored electronically, allowing them to be
retrieved and revised. The software provides tools to correct spelling and grammatical
mistakes, permits copying and moving text without rekeying, and provides tools to
enhance the format of documents. Electronic spreadsheet software is used in business
environments to perform numeric calculations rapidly and accurately. Data are keyed
into rows and columns on a worksheet, and formulas and functions are used to make
fast and accurate calculations. Spreadsheets are used for "what-if" analyses and for
creating charts based on information in a worksheet. A database is a collection of data
organized in a manner that allows access, retrieval, and use of that data. A database
management system (DBMS) is used to create a computerized database; add,
change, and delete data; sort and retrieve data from the database; and create forms
and reports using the data in the database. Presentation graphics software is used to
create presentations, which can include clip-art images, pictures, video clips, and
audio clips as well as text. A personal information manager is a software application
that includes an appointment calendar, address book, and notepad to help organize
personal information such as appointments and task lists. Engineers, architects,
desktop publishers, and graphic artists often use graphics and multimedia software
such as computer-aided design, desktop publishing, video and audio entertainment,
and Web page authoring. Software for communications includes groupware, e-mail,
and Web browsers.

9

1.9

Hardware

Information processing involves four phases: input, process, output, and storage. Each
of these phases and the associated devices are discussed below.
Input devices: Input devices include the keyboard, pointing devices, scanners and
reading devices, digital cameras, audio and video input devices, and input devices for
physically challenged users. Input devices are used to capture data at the earliest
possible point in the workflow, so that the data are accurate and readily available for
processing.
Processing: After data are captured, they are processed. When data are processed,
they are transformed from raw facts into meaningful information. A variety of
processes may be performed on the data, such as adding, subtracting, dividing,
multiplying, sorting, organizing, formatting, comparing, and graphing. After processing,
information is output, as a printed report, for example, or stored as files.
Output devices: Four common types of output are text, graphics, audio, and video.
Once information has been processed, it can be listened to through speakers or a
headset, printed onto paper, or displayed on a monitor. An output device is any
computer component capable of conveying information to a user. Commonly used
output devices include display devices, printers, speakers, headsets, data projectors,
fax machines, and multifunction devices. A multifunction device is a single piece of
equipment that looks like a copy machine but provides the functionality of a printer,
scanner, copy machine, and perhaps a fax machine.
Storage devices: Storage devices retain items such as data, instructions, and
information for retrieval and future use. They include floppy disks or diskettes, hard
disks, compact discs (both read-only and disc-recordable), tapes, PC cards, Smart
Cards, microfilm, and microfiche

10

1.10 Information and Data Processing
Data processing is the input, verification, organization, storage, retrieval,
transformation, and extraction of information from data. The term is usually associated
with commercial applications such as inventory control or payroll. An information
system refers to business applications of computers and consists of the databases,
application programs, and manual and machine procedures and computer systems
that process data. Databases store the master files of the business and its transaction
files. Application programs provide the data entry, updating, and query and report
processing. Manual procedures document the workflow, showing how the data are
obtained for input and how the system's output is distributed. Machine procedures
instruct the computers how to perform batch-processing activities, in which the output
of one program is automatically fed into another program. Daily processing is the
interactive, real-time processing of transactions. Batch-processing programs are run at
the end of the day (or some other period) to update the master files that have not been
updated since the last cycle. Reports are printed for the cycle's activities. Periodic
processing of an information system involves updating of the master files— adding,
deleting, and changing the information about customers, employees, vendors, and
products.

11

2

User – Interface

The user interface is the part of every device that determines how people control and
operate that device. When the interface is well designed, it is comprehensible,
predictable, and controllable; users feel competent, satisfied and responsible for their
actions.

2.1

2.1.1

Input Devices

Keyboard

The keys on a keyboard allow you to enter information and instructions into a
computer. The following is a list of the main keyboard features:

Fig. 1

-

Connection Types: A keyboard can connect to a computer through a PS/2
(keyboard) or Universal Serial Bus connection. Some keyboards run on a battery
and connect wirelessly to the computer. A wireless keyboard reduces clutter on
your desk by eliminating the keyboard cord and allows you to sit up to 30 feet away
from a computer.

12

-

QWERTY Keyboards: The most common type of keyboard is known as a
QWERTY keyboard, which refers to how the keys are positioned on the keyboard.
On this type of keyboard, the first six characters on the top line of alphabetic keys
are Q, W, E, R, T and Y.

-

Finger Position Guides: Most keyboards have small bumps on the F and J keys
that help you position your fingers without looking at the keyboard.

2.1.1.1 Prevent Typing Injuries


Ergonomic Keyboards: Ergonomic Keyboards, which consist of separate
sections if keys, allow you to position your hands more naturally so you can
work more comfortably. Ergonomic keyboard scan also help prevent a
repetitive strain injury, such as carpal tunnel syndrome.



Wrist Rests: You can use wrist rest with your keyboard to ensure your wrist
remain elevated and straight while you type. Using a wrist rest with a keyboard
wick prevent you form resting your wrists on the edge of a desk a position
which can cause wrist injury. Some keyboards come with a built-in wrist rest.
You can also purchase a wrist rest for your keyboard separately.



Take Breaks: You should take frequent breaks when typing to prevent hand
and wrist strain that can lead to typing injuries. You should stretch or perform
other tasks for 15 minutes after every hour or two tying.



Clean a Keyboard: Over time, dust and dirt can accumulate on you keyboard,
causing the keys to stick or not respond when pressed, To remove the dust
and dirt you can use a vacuum cleaner over the keys.



The plastic outer surface of the keyboard can be cleaned with a damp cloth.
You should not attempt to open your keyboard to clean inside, as this may
result in damage to the key board.



Most keyboards have 101 keys and they include some or all of the following
keys:



Function Keys: These keys allow you to quickly perform specific tasks. For
example, in many programs, you can press f1 to display help information.

13



Hot Keys: Each of these buttons allows you to perform a certain task, such as
opening your Web browser, launching your email program or adjusting your
computers volume setting.



Backspace Key: You can press Backspace to remove the character to the left if
the cursor.



Insert Key: You can press Insert to type over existing text in a document. Press
the key again to stop your typing from replacing existing text.



Delete Key: You can press the Delete button to remove the character to the
right of the cursor or delete the selected item.



Status Lights: These lights indicate whether the Num Lock and Caps Lock
features

are on or off



Escape Key: You can press Esc to quit a task you are performing.



Tab Key: You can press Tab to move to the next tabbed location in a
document.



Caps Lock and Shift Keys: These keys allow you to enter text in uppercase
(ABC) and lowercase (abc) letters.



Press Caps Lock to change the case of all letters you type. Press the key again
to return to the original case. Press Shift in combination with another key to
type an uppercase letter.



Ctrl and Alt Keys: You can use the Ctrl or Alt key in combination with another
key to perform a specific task. For example, in some programs, you can press
Ctrl and S to save a document.



Windows Key: You can press this key to quickly display the Start menu when
using the Windows operating system, such as Windows XP.



Spacebar: You can press the Spacebar to insert a blank space.



Application Key: You can press this key to quickly display the shortcut men for
an item on your screen.



Enter Key: You can press Enter to tell the computer to carry out a task. In a
word processing program, press this key to start a new line or paragraph.



Arrow Keys: These Keys allow you to move the cursor around the screen.

14

2.1.2

Pointing Devises

2.1.2.1 Mouse

A mouse is a handheld device that allows you to select and move items on your
screen. A mouse can be bought in various shapes colors and sizes. When you move a
mouse on a flat surface, this causes the pointer on the screen to move in the same
direction.

Fig. 2

15

Below is a list of common mouse features:



Buttons: Most mice have two buttons that can be pressed and released, or
“click”, to perform an action. Some mice have more than two buttons. Theses
additional buttons may be pre-programmed or you may be able to program the
buttons to perform specific tasks, such as starting a Web browser.



Wheels: Most mice have a wheel between the left and right buttons. You can
use this wheel to scroll through information in documents and on the Web.



Connection Types: A mouse can connect to a computer through a serial, PS/2
(mouse) or a Universal Serial Bus connection. Some mice run on a battery and
connect wirelessly to the computer. When a wireless mouse is moved, the
mouse sends signals to your computer or to a device attached to your
computer. A wireless mouse will reduce the clutter on your desk as it eliminates
the mouse cord.

2.1.2.2 Types of Mice


Mechanical Mouse: A mechanical mouse detects mouse movement using a
ball on the bottom of the mouse which rolls as the mouse is moved. This type
of mouse needs regular cleaning to remove dust and dirt from inside the mouse
and ensure smooth motion. You should use a mouse pad to provide a smooth
surface for moving the mouse and to reduce the amount of dirt that enters the
mouse.



Optical Mouse: An optical mouse detects mouse movement using a beam of
light. This type of mouse does not contain any moving parts that can wear out
or require cleaning. You do not need to use a mouse pad when using an optical
mouse, but for best results you should use the mouse on a flat surface that is a
solid color.

16

2.1.2.3 Other Pointing Devices


Trackball: A trackball is an upside down mouse that remains stationary on your
desk. You roll the ball with your fingers or palm to move the pointer on the
screen. Trackballs usually include buttons that you can use the same way you
use the buttons on a mouse. A trackball is a great alternative to a mouse when
you have limited desk space.



Tablet: A tablet consists of a flat surface and a pen, called a stylus. When you
move the stylus on the surface of the tablet, the mouse pointer moves on the
computer screen. Tablets are most often used for performing tasks that require
speed and precision, such as graphic design and image editing. Tablets, also
known as digitizer tablets and graphics tablets, also often come with a mouse
that you can use in addition to the stylus.

2.1.3

Source Data-Entry Devices

2.1.3.1 Modem

A modem allows a computer to send and receive information through a telephone line.
A modem translates computer information into a form that can transmit over telephone
lines.

A modem also translates the information it receives into a form a computer can
understand. We can distinguish between two types of modems, internal and external.

Internal Modem: Most new computers come with an internal modem. An internal
modem may be a circuit board that plugs into an expansion slot inside a computer or
may be built into the motherboard of a computer. An internal modem is generally less
expensive than an external modem.

17

Fig.3a

External Modem: AN external modem is a small device that connects to a computer by
USB (Universal Serial Bus) or serial connection. Modems that use USB connection are
easier to set up than modems that use a serial connection. An external modem takes
up room on your desk, but can be moved and used with other computers. Most
external modems have lights to indicate the status of the modem and whether the
modem is working properly.

Fig. 3b

Most modems available today can transfer information at speeds up to56 Kilobits per
second (56K), depending on the quality of the telephone line connection. Modem
standards ensure that modems made by different manufacturers can communicate
with each other. V.92 is the current standard for 56K modems.

18

Modem Features:


Phone Line Use: You can use the same telephone line for telephone and
modem calls. If you have a call waiting feature, you can use software, often
referred to as modem- on- hold software, which allows you to accept an
incoming telephone call without losing your modem connection. If you do not
use this type of software, make sure the call waiting feature is disabled when
you use the modem, since the call waiting feature could disrupt the modem
connection.



Assess Information: You can use a modem to connect to the Internet to browse
the Web and exchange e-mail. When travelling or at home, you can use a
modem to access information, such as office files and e-mail, stored on the
network at work.



Send and Receive Faxes: Most modems can send and receive faxes. With a
fax modem, you can create a document on your computer and then fax the
document to another computer or fax machine. When you receive a fax using a
modem, you can view the fax on your computer screen, which helps to
conserve paper.



Voice Capabilities: Some modems allow you to connect your telephone to the
modem so you can use a computer to send and receive telephone calls. You
can attach a microphone to your computer to use the computer as a hands free
telephone or use special software to turn your computer into an answering
machine.

2.1.3.2 Scanner

A scanner is a device that reads images and text from paper into a computer. You can
scan images, such as photographs and drawings, into a computer. You can then use
the scanned images in documents, presentations and Web pages or e-mail the images
to friends and family members. Most scanners come with image editing software,
which allows you to change the appearance of a scanned image, such as removing
red-eye from a photograph.

19

Fig. 4

You can scan documents store them electronically on your computer. You can then
quickly access documents on your computer and e-mail them to friends and
colleagues. Most scanners come with Optical Character Recognition (OCR) software,
which places scanned text into a document that you can edit in a word processor.

Most scanners are flatbed scanners as illustrated above. Like using a photocopier, you
place images or documents you want to scan face down on the surface of a flatbed
scanner. Flatbed scanners can scan flat objects such as photos and documents, thick
objects such as a book and portions or oversized objects such as maps and charts. A
flatbed scanner may be horizontal or vertical. Vertical flatbed scanners take up less
space on your desk. Most new flatbed scanners connect to a computer through a SUB
(Universal Serial Bus) or FireWire connection.

The resolution of a scanner determines the amount of detail a scanner can detect and
is measured in dots per inch (dpi). A higher resolution results in more detailed images.
The resolution of a scanner is often expressed with two numbers, such as 2400 X

20

2400 dpi, which define the number of dots a scanner can detect across and down one
square inch. The resolution may also be expressed with only one number, such as 300
dpi, which defines the number of dots a scanner can detect both across and down one
square inch. A resolution of 300 dpi is sufficient for images you will print, while 72 dpi
is adequate for images you will display on monitor, such as on Web page.

The color, or bit, depth of a scanner indicates the number of colors a scanner can
detect and is measured in bits. The higher the color depth, the higher the quality of the
scanned images is. You should buy a scanner capable of at least 16.7 million colors
(24 – bit). In addition, you should look for a scanner capable of at least 256 shades of
gray (8 –bit) if you plan to san many black and white photos or images.

Scanner Features:

Most scanners can scan documents that measure 8.5 by 11 inches, but some
scanners offer a larger maximum scan size.
Some scanners include an automatic document feeder that allows you to scan multiple
pages unattended.
Some scanners allow you to scan transparencies, slides and film negatives.
If you plan on scanning a lot of images or documents, look for a fast scanner. The
speed of a scanner may be indicated in seconds per page.
Scanners often come with one touch buttons that allow you to instantly perform a task,
such as scan or e-mail a scanned document.

21

2.1.4

Audio Input Devices

2.1.4.1 Sound Card

A sound card allows a computer to play record and process sounds. Most computers
come with basic sound capabilities, which are often built into the main circuit board of
a computer. You can add a higher quality sound card to a computer to greatly improve
the sound generated by the computer. A sound card is also called a sound board or
audio card.

Fig. 5

Sound Card Applications:

Play Sounds: A sound card allows you to hear music when using your computer to
play music CDs. A sound card also allows you to hear speech sound effects and music
when playing games and when viewing videos, DVD movies, Web pages and
multimedia presentations. Sound cards also allow you to hear sounds generated by a
computer, such as the “You’ve Got Mail” recording when you receive an e-mail
message.

22

They also allow you to connect a musical instrument, such as an electronic keyboard,
or to a computer to use it to compose music. You can also use a sound card and voice
recognition software to be able to use your voice to instruct a computer to perform
tasks. Sound cards also allow you to talk to friends, family members and colleagues
over the Internet.
Sound cards allow you to record music from music CDs as well as use a microphone
to record your own voice or sound effects. You can add the sounds you record to
documents, presentations and home movies you create.

A sound card has several connections, called jacks or ports, where you can plug in
external devices. Here are some common connections you will see on a sound card.


Microphone In: This jack allows you to connect a microphone to record speech
and other sounds.



FireWire and USB: Some sound cads offer one or more FireWire or USB
(Universal Serial Bus) ports that allow you to connect devices such as a digital
camera or digital camcorder. A sound card that includes a FireWire or USB port
provides you computer with an extra port and is especially useful if your
computer does not already have the port.



Line In or Digital In: The line in jack allows you to connect an external sound
source, such as a VCR or tape deck. A digital in jack allows you to connect an
external digital sound source, such as a CD-ROM player or game console,
which provides superior sound quality.



Line Out or Digital Out: The line out jack allows you to connect speakers,
headphones or an external receiver, or amplifier, which can connect to
speakers or home stereo system. A digital out jack allows you to connect an
external digital sound source, which provides superior sound quality.

23

Types of Sound Cards:


Internal Sound Card: You can enhance the quality of sound generated by a
computer by adding a higher quality, internal sound card. An internal sound
card is a circuit board that plugs into an expansion slot inside a computer. Most
internal sounds cards are OCI (Peripheral Component Interconnect) sound
cards, which defines the type of slot the sound card plugs into.



External Sound Device: An external sound device usually connects to a
computer through a USB (Universal Serial Bus) connection. An external sound
device takes up room on your desk, but is easier to set up and can be moved
and used with other computers. External sound devices usually produce higher
quality sound than internal sound cards, but are generally more expensive.



Surround Sound: Basic sound cards allow you to connect two speakers to
produce stereo sound. Many sound cards now offer surround sound, which
allows you to place multiple speakers around the computer so the sound
generated by the computer “surrounds” you. Surround sound is ideal when
watching movies and playing games. Two popular types of surround sound
include Dolby Digital and DTS. 5.1 surround sounds allows you to connect five
speakers as well as a subwoofer to produce the low sounds. The .1 refers to
the subwoofer. You can also obtain sound cards that provide 6.1 and 7.1
surround sound, allowing you to connect six or seven speakers and a
subwoofer to the sound card.



The number of bits indicates the number of sounds a sound card can process.
The higher the number of bits, the higher the quality of the sound is. For
example, 16 bit refers to 65,536 sound levels and 24 bit refers to 16.7 million
sound levels. Most high end sound cards are 24 bit.

Sound Blaster sound cards are the industry standard for sound cards. Most sound
cards and software applications are marked as Sound Blaster compatible. Make sure
the sound card you buy is Sound Blaster compatible.
Application Programming Interfaces (APIs) are special functions a game or program
will use to communicate with your sound card. If your game or program uses specific
APIs, your sound card must support them. Some popular APIs include DirectSound,
EAX and MacroFX.

24

2.1.5

Video Input Devices

A video card is an expansion card that generates the images displayed on computer’s
monitor.

You can see the edge of a video card at the back of a computer. A video card has
several ports where you can plug in external devices. A video card is also known as a
graphics card, video adapter or graphics adapter.

S-Video or TV Out Port, allows you to connect a television or projector.
Digital Input (DVI) Port, allows you to connect an LCD monitor or digital television.
VGA Port, allows you to connect a CRT monitor.

Video Slots: There are two main ways that a video card connects to a computer by
plugging into an AGP slot or into a PCIe slot.

Fig. 6

25



AGP: An Accelerated Graphics Port (AGP) video card plugs into an AGP slot in
a computer. The AGP slot allows the video card to communicate directly with
the computer’s main memory and quickly display complex images on your
monitor. Currently the fastest version of AGP is AGP 8x.



PCIe: A Peripheral Component Interconnect Express (PCIe) video card plugs
into a PCIe slot in a computer. PCIe allows the video card to send and receive
information from the computer’s main memory at the same time for fast display
of images. PCIs is a newer, faster type of slot found in high end computers.
There are several versions of PCIs, but PCIe x16 is the version most often
used for video cards.



Many entry level computers include integrated graphics instead of a video card.
When a computer has integrated graphics, the computer’s memory (RAM) is
shared between processing information and displaying images. This type of
graphics system reduces the overall cost of a computer but can slow down the
computer’s performance because the RAM is used to temporarily store video
information. Integrated graphics is adequate for performing day to day tasks on
a computer, but will not provide good performance for games or graphic
intensive applications.



A high end video card is designed to produce faster and smoother graphics
when playing games or using photo or video editing software. A high end video
card has its own memory as well as a specialized chip, called a Graphics
Processing Unit (GPU) or Video Processing Unit (VPU), that is optimized to
produce 3D images.



A GPU allows a video card to display images on the screen without using your
computer’s processor, which improves you computer’s overall performance.
ATI and nVidia are popular high end video card manufacturers.



TV Tuner Card: A TV tuner card allows you to watch television programs on
your computer. Most TV tuner cards also allow you to save still images and full
motion video clips from a television program on your hard drive.

26

A TV tuner card can be a separate expansion card that plugs into an expansion
slot. Video cards that have TV tuner card capabilities built in, known as all in one
cards, are also available.

Amount of Memory: A video card contains memory chips that temporarily store
information before sending it to the monitor. If you use professional graphics
applications or play graphics intensive games, you should have a video card with
at least 128 MB of memory.

A video card with a large amount of memory will be capable of providing a higher
refresh rate, resolution and color depth than a video card with a smaller amount of
memory.

SDRAM (Synchronous Dynamic Random Access Memory) and DDR SDRAM
(Double Data Rate SDRAM) are the most common types of memory found on
video cards, DDR SDRAM, also known as DDR, can process information
approximately twice as fast as SDRAM. There are several versions of DDR used
on video cards, including DDR2, DDR3 and GDDR3 (Graphics DDR3). The higher the
number, the faster the memory ships can process information.

DirectX is a set of applications that provide exceptional performance in games and
videos for computers using the Windows operating system. Most video cards are
optimized to support DirectX.

The refresh rate determines the speed that a CRT monitor updates images on the
screen. Your video card must be able to use the same refresh rate as your
monitor. Most monitors can detect which refresh rate the video card is using and
them automatically switch to the appropriate setting. A refresh rate of 72 hertz (Hz)
or more is recommended.

Resolution is the number of horizontal and vertical dots, called pixels, displayed on
a screen. Higher resolutions display smaller images so you can display more

27

information on your screen at once, while lower resolutions display larger images
so you can see information more clearly. Your video card must be able to use the
same resolution as your monitor.

The video card you use determines the number of colors a monitor can display.
More colors result in more realistic images. Most video cards sold today are
capable of supporting 32-bit color, or over 4 billion colors. If your video card does
not have adequate memory, you may not be able to use a high color depth if your
computer is set at a high resolution.

2.2

2.2.1

Output Devices

Display Screens

Monitors can be separated into two categories. Below is a description of those two
and some important distinctions between each one.

Fig. 7

28



CRT Monitors: Cathode Ray Tube (CRT) monitors use the same technology as
most television sets. CRT monitors are relatively inexpensive and display
brighter images than LCD monitors, but are heavy, difficult to move and take up
a lot of desk space. CRT monitors also use more electricity and emit more
electromagnetic radiation than LCD monitors. CRT monitors are becoming less
popular as the price of LCD monitors decreases.



LCD Monitors: Liquid Crystal Display (LCD) monitors use the same type of
display found in notebook computers. These monitors use active matrix
technology, or thin film transistor (TFT) technology, to produce images. LCD
monitors, also known as flat panel monitors, are thin, stylish and lightweight.
They also take up less desk space, use less electricity and emit less
electromagnetic radiation than CRT monitors. LCD monitors, however, are
relatively expensive and can be difficult to view from the side and in bright
sunlight.



Common Sizes: The size of a monitor is measured diagonally across the
screen. Monitor sizes range from 15 to 30inches, but are typically 17 or 19
inches. Larger monitors are more expensive, but can display more information
at once.

Manufactures often advertise the diagonal measurement of the picture tube inside a
CRT monitor, which is one to two inches larger than the viewing area. Make sure you
are aware of the size of the viewing area before purchasing a CRT monitor. LCD
monitors always indicate the size of the viewing area.

Resolution:

Commonly Used Resolutions: The resolution is the number of horizontal and vertical
dots, called pixels, displayed on a screen. The most commonly used resolutions are
1,024 x 768, which is also known as XGA (Extended Graphics Array), and 1,20 x
1,024, which is also known as SXGA (Super XGA).

29

Adjust the Resolution: Most CRT monitors allow you to adjust the resolution to suit
your needs. The resolution you choose depends on the size or your monitor and the
amount of information you want to display on your screen at once. Lower resolutions
display larger images so you can see information more clearly, while higher resolutions
display smaller images so you can display more information on you screen at once.
You will usually not change the resolution of an LCD monitor since this can greatly
reduce the image quality.

Dot Pitch:

The dot pitch is the distance between dots, called pixels, which make up an image on
a screen. The dot pitch determines the sharpness of images on a monitor and is
measured in millimeters (mm). The smaller the dot pitch, the sharper the images are.
For example, a CRT monitor with a dot pitch of 0.26 mm or less is ideal.


Brightness: The brightness of a monitor is measured in candelas per square meter
(cd/m) or nits. A higher number indicates a brighter screen. Brighter monitors
display richer colors, function better in locations with a lot of natural light and help
reduce eyestrain. For example, a brightness of over 250cd/m is ideal for an LCD
monitor.



Contrast Ratio: For an LCD monitor, the contrast ratio refers to the difference
between the brightest white and the darkest black that a monitor can produce. The
higher the contrast ratio, the better the monitor’s ability to show subtle color details
is (which is ideal for playing games and watching movies). An LCD monitor with a
contrast ratio of at least 400:1 is ideal.



Control: A monitor has controls you can use to adjust the images displayed on the
screen. For example, you can use the controls on a CRT monitor to change the
brightness and contrast of the display. The controls are usually located on the
bottom edge of the front of a CRT monitor, but can also be accessed through an
on-screen menu.

30



Tilt and Swivel Base: Many monitors allow you to tilt the monitor up and down and
swivel the monitor from side to side to obtain a better viewing angle and help
reduce the glare from overhead lighting.



Monitor Rotation: You can physically rotate some LCD monitors from landscape
mode, in which the monitor is wider than it is tall, to portrait mode, in which the
monitor is taller than it is wide. This feature can be useful when working with
documents or browsing the web.



Refresh Rate: For CRT monitors, the refresh rate determines the speed that a
monitor redraws, or updates, images on the screen. A higher refresh rate reduces
flicker on the screen which helps to reduce eyestrain. The refresh rate is measured
in hertz (Hz) and tells you the number of times per second the monitor redraws the
entire screen. A CRT monitor with a refresh rate of 72 HZ or more is
recommended.



Response Time: For an LCD monitor, the response time indicates how fast the
monitor can display changes on the screen. When information changes on the
screen, a ghosting effect may occur, which means the previous information
remains on the screen after the new information appears. The lower the response
time, the faster the images on the screen update, which reduces the ghosting
effect. You should look for an LCD monitor with a response time of 16 milliseconds
(ms) or less.



Energy Star: In general, an LCD monitor uses less electricity than a CRT monitor.
To help conserve even more electricity, the Environmental Protection Agency
(EPA) developed an energy-saving guideline called Energy Star. Most new CRT
and LCD monitors are Energy Star complaint. When you do not use an Energy
Star monitor for period of time, the monitor enters and energy-saving sleep mode,
which uses significantly less electricity. You can awaken the monitor at any time by
moving the mouse or pressing a key on the keyboard. Energy Star monitors last
longer and save you money.

31



Monitor Filters: You can obtain a filter that fits over the front of a monitor to
decrease the amount of light reflected off the computer screen and reduce
eyestrain. Many filters can also block the electromagnetic radiation produced by a
monitor.



Privacy filters are also available that make the screen difficult to read when viewed
from an angle, which helps keep your work private.



Electromagnetic

Radiation:

Any

device

that

uses

electricity

produces

Electromagnetic Radiation (EMR). You can minimize the risk of EMR by buying a
monitor that meets MPR or TCO guidelines, which define acceptable levels of
EMR.


You can further minimize the risk of EMR by purchasing a smaller monitor, sitting a
safe distance away from a monitor, buying an LCD monitor instead of a CRT
monitor and turning off a monitor when it is not in use.



Flat-Screen: Some CRT monitors gave a flat screen instead of the curved screen
offered by most CRT monitors. Flat-screen CRT monitors provide a sharper image
and reduce glare, but are more expensive than monitors with a curved screen.



Widescreen: Some LCD monitors have a wide screen. A wide screen is ideal for
viewing widescreen DVD movies, watching high-definition television and playing
games designed for widescreen play.



Built-In Speakers: Some monitors have built-in speakers, which can save desk
space. Keep in mind, though, that the sound quality produced by built-in speakers
tends to be lower that the sound quality produced by standalone speakers.



Digital Input: Many LCD monitors offer a digital connection, known as DVI (Digital
Video Interface), between the video card and the monitor. If your computer has a
digital video card, using the DVI connector to connect your LCD monitor to the
computer can result in sharper images and better color quality.

32

If your computer does not offer a DVI connection, an LCD monitor must use an analog
connection to connect to the computer. When using an analog connection, the monitor
must translate the analog signal coming from the video card to a digital signal the
monitor can use to display an image on the screen

2.2.2

Printers

A printer is a device that produces a paper copy of the information displayed on a
computer screen. You can use a printer to produce letters, invoices, newsletters,
labels envelopes, photos, transparencies and many more.

Fig. 8

An all-in-one printer can perform more than one task. Most all-in-one printers can work
as a printer, photocopier and scanner, while some can also work as a fax machine. Allin-one printers are lees expensive and require less space than the multiple pieces of
equipment that perform the same tasks. Although all-in-one printers can perform many
tasks, they may not offer all the features provided by a standalone printer, photocopier,

33

fax machine, scanner and printer. All-in-one printers are also known as multifunction
printers.

All-In-One Printer Considerations

-

Many all-in-one printers allow you to make black and white photocopies as well as
color photocopies.

-

Some all-in-one printers include a sheet fed scanner, which scans single sheets of
paper. Other all-in-one printers include a flatbed scanner, which allows you to
place thick items you want to scan on a flat surface. If you want to use an all in one
printer as a standalone fax machine. Look for a complete set of fax controls on the
printer so you can send and receive faxes when you computer is turned off.

You can buy all in one printers in inkjet or laser printer format.

Inkjet Printers:

An inkjet printer sprays ink into onto a page and prints each page one line at a time.
And inkjet printer produces good quality text and graphics and high quality photos.
Although an inkjet printer is cheaper than a laser printer, the cost per page is more
expensive. An inkjet printer is slower than a laser printer, especially when printing long
documents.

Inkjet printers use ink stored in cartridges. Color inkjet printers use four separate
colors, which are yellow, black, cyan and magenta, to produce printed pages. Some
inkjet printers use two ink cartridges, one containing only black ink and one containing
all the other colors, while other inkjet printers use a separate ink cartridge for each
color. Using a separate ink cartridge for each color can save you money since you do
not have to throw out all the colors when one color runs out.

34

When an ink cartridge runs out, you need to buy a new ink cartridge designed for your
printer. You can save money and the environment by having an ink cartridge refilled
with ink instead of buying a new cartridge.

Laser Printers:

A laser printer uses a laser beam to print an entire page all at once. This allows
lasers printers to offer fast print speeds, which makes them ideal for printing long,
complex documents.

Laser printers produce high quality text and graphics and good quality photos. You
can buy color and monochrome, or black and white laser printers. A laser printer is
more expensive to buy than an inkjet printer, but the cost per page is cheaper.

Light Emitting Diode (LED) printers are similar to laser printers but they do no t use
a laser beam. LED printers are generally less expensive and smaller than laser
printers.

Laser printers use a fine powered ink, called toner, which comes in a cartridge.
Black and white laser printers use one cartridge that stores black ink. Color laser
printers usually have a separate cartridge for each color. The colors are magenta,
black, yellow and cyan. When a toner cartridge runs out, you will need to buy a
new cartridge designed for your printer. You can save money and the environment
by having a cartridge refilled with toner instead of buying a new cartridge.

-

Printer Languages: A printer language describes how text and graphics should
appear on a printed page. There are two types of laser printer languages which are
PCL and PostScript.

-

PCL: Most printers come with Printer Control Language (PCL). A page printed on a
PCL printer may look different when printed on another laser printer.

-

PostScript: Some laser printers offer the PostScript printer language. A page will
print exactly the same way on any PostScript printer.

35

Photo Printers:

A photo printer is usually an inkjet printer that is specifically designed to print
photographs. Photo printers can produce true photo quality, which means photos
printed on a photo printer are indistinguishable from prints produced at photo shops.

Photo printers use the same ink cartridges as inkjet printers. Photo printers use the
standard colors magenta, yellow, black and cyan. However many also offer additional
colors such as light magenta and light cyan. More ink colors help to widen the range of
colors the printer can produce and make colors such as skin tones easier to
reproduce. If you plan to print a lot of black and whit photos, look for a printer that uses
a gray ink.


Speed: The speed of a printer indicates how quickly a printer can print pages and
is measures in pages per minute (ppm).Printer manufactures usually indicate the
speed at which a printer can produce black and white documents. If a printer can
print in color, the speed for color documents is also usually given. If a printer can
print photos, a manufacturer may indicate the print speed for a 4 x 6 photo and an
8 x 10 photo in seconds or minutes.



Resolution: The resolution of a printer determines the quality of the text and
images a printer can produce. A higher resolution results in sharper, more detailed
images. The resolution of a printer is measured in dots per inch (dpi) and is usually
expressed by two numbers, such as 1200 x 600 dpi, or by only one number, such
as 600 dpi.



Black& White versus Color: If a printer can print in color, the manufacturer will
usually provide the resolution for printing black and white documents as well as
color documents. Generally, a resolution of 600 dpi insufficient for most text
documents and photos and 1200 dpi works well for printing artwork.



Sheet Capacity: Printers can hold a certain amount of paper at one time. A lower
sheet capacity means you will have to refill the paper tray more often.

36



Paper Size: Most printer scan print on 8.5 x 11 inch paper. Some printers can print
on larger paper sizes, such as legal paper, which is 8.5 x 14 inches. Make sure the
printer you choose can print the size of paper you plan to use.



Memory: Laser printers and some inkjet printers store documents you select to
print in built in memory before printing. The amount of memory a printer offers is
usually measured in megabytes (MB). More memory increases the printing speed
when printing long or complex documents. Some printers allow you to add memory
modules to the printer. Printer manufacturers usually indicate the amount of
memory installed and the maximum amount of memory you can add to a printer.



Types of paper: Each printer can print on different types of paper and materials,
such as envelopes, labels, photo paper, transparencies and iron on transfers.
Make sure the printer you choose can print on the type of paper and material you
plan to use.



Types of Connections: Printers usually connect to a computer through a Universal
Serial Bus (USB), parallel or network (Ethernet) connection. A parallel port offers
the slowest type of connection to a computer. A network connection is useful if you
want to connect a printer directly to a network so more than one computer can use
the printer.

37

2.2.3

Audio-output devices

Speakers:
Speakers allow you to hear the sound generated by your computer. When using your
computer to listen to music CDs, play games and watch DVD movies, higher quality
speakers can make the sound generated by your computer seem more realistic.
Higher quality speakers can also play sounds more clearly when you turn up the
volume.

When choosing speakers, make sure you select shielded speakers. Shielded speakers
prevent the magnets inside the speakers from distorting the images on a monitor.

Speaker systems commonly have between two and seven speakers, or channels. A
speaker system that contains more than two speakers allows you to experience
surround sound. Surround sound allows you to place multiple speakers around a
computer so the sound generated by the computer “surrounds” you. Surround sound is
ideal when using your computer to watch movies and play games.

Many speaker systems include a subwoofer, referred to as .1, to produce low sounds.
A subwoofer is usually placed on the floor and away from objects to prevent objects
from vibrating. When a speaker system includes a subwoofer, each individual speaker
in the speaker system is often referred to as a satellite speaker.

All speakers need is an amplifier to boost the volume of the sound generated by a
computer. Passive speakers do not have a built in amplifier and require an external
amplifier, called a receiver, to boost the volume. Active speakers have a built in
amplifier, which is specifically designed to work with the speakers.

Manufacturers will indicated the maximum power output per speaker and the total
power output for the entire speaker system in watts (W). The higher the power output,
the higher the maximum volume your speakers can produce.

38

The Signal to Noise Ration (SNR) compares the sound played, known as the signal, to
the unwanted noise you hear when no sound is played, such as humming, hissing and
crackling noises. The signal to noise ration is measured in decibels (dB). A higher
signal to noise ration means more signal and less noise, resulting in better sound
quality. Higher quality speakers will have a signal to noise ration of90 dB or more.

Frequency response is measured in hertz (Hz) and refers to the range of low to high
sounds that speakers can produce. The range of human hearing is 20 Hz to 20 kHz.
High quality speakers have a frequency of 60 Hz to 20 kHz. Keep in mind that higher
quality speakers will more accurately reproduce sounds in a given range of
frequencies than lower quality speakers.

Headphones:
Headphones allow you to listen privately to the sound generated by your computer as
well as listen to the sound generated by portable devices, such as an MP3 player or
cell phone. Higher quality headphones can make the sound generated by a computer
or portable device seem more realistic. Higher quality headphones can also play
sound more clearly when you turn up the volume.

Types of Headphones:


Headphones: Headphones have earpieces that sit on your ear or fit tightly around
your ear. The band between the earpieces may rest on the top of your head or
behind your neck. Headphones are ideal for listening to high quality music
privately.



Headsets: Headsets are headphones with an attached microphone. Headsets are
ideal for any situation in which you want to listen and talk at the same time. For
example, headsets are useful for chatting with other people on the Internet and
working speech recognition software. You can also use headsets with cell phones,
for hands free talking and listening.

39



Ear buds: Ear buds are small, lightweight headphones that are ideal to use when
exercising. Ear buds work well with portable devices, but usually provide lower
quality sound than headphones or headsets. Basic ear buds are often packaged
with MP3 players.

Headphone Features:


Types of Connections: Most headphones have a round connector or a USB
(Universal Serial Bus) connector that plugs into a jack or port on a computer or
portable device. When purchasing headphones, you should make sure the
headphones have the appropriate connector for your computer or device.



You can also buy Bluetooth, or wireless, headphones that allow you greater
freedom of movement because there is no headphone cord to get in your way. You
can use Bluetooth headphones with a Bluetooth enabled computer, cell phone or
other portable device.



High quality headphones are able to remove outside noises to provide you with a
better listening experience. Headphones with noise cancellation capability are ideal
when you want to use your headphones in a noisy location, such as on a crowded
airplane or at the gym.



Frequency response is measured in hertz (Hz) and refers to the range of low to
high sounds that headphones can produce. The range of human hearing is 20 Hz
to 20 kHz. High quality headphones can also have a frequency range of 20 Hz to
20 kHz, while lower quality headphones offer a smaller frequency range.

40

Web Camera:

A Web camera is a device that allows you to record video that you can save on your
computer or share over the Internet. Most Web cameras, also known as webcams,
attach to your computer using a cable.

Fig. 9

Web cameras are often used for videoconferencing which allows you to have face to
face conversations with people on the Internet or other networks. Your computer must
have a sound card, speakers and a microphone to transmit and receive sound during a
videoconference.

There are many ways you can work with the videos transmitted to your computer by a
Web camera. For example, you can send live video of yourself while exchanging
instant messages with friends or colleagues on the Internet. You may also want to use
a Web camera to place live video on a Web page you create.

41

The speed and resolution of a Web camera determine the quality of images the
camera can produce. Web cameras often offer several speeds and resolutions you
can choose from. Faster speeds can reduce choppiness in a video. Higher resolutions
produce larger and more detailed video, but may reduce the speed. Web cameras can
commonly transfer video at a speed of up to 30 frames per second and a resolution of
up to 640 x 480 pixels.

Web Camera Features:


Software: Web cameras usually come with software that helps you set up and
use the web camera. You can often use this software to adjust the camera’s
settings, such as the brightness and contrast settings. A Web camera may also
come with software that offers advanced features, such as video editing
software.



Motion Sensing Capabilities: Some Web cameras have motion sensing
capabilities, allowing the cameras to begin transferring or recording video when
they detect movement. This feature is useful if you want to use a Web camera
as a security camera.



Some Web cameras also have a face tracking feature, which enable the
camera to move and stay focused on your face even when you change position
or stand up.



Wireless Web Cameras: Some Web cameras do not need to be connected to a
computer when transferring or recording video. A wireless Web camera uses a
transmitter to transfer video to a receiver connected to the computer. The Web
camera must usually be within a certain range of the receiver to operate, such
as 100 feet.



Digital Camera Capabilities: Most Web cameras have digital camera
capabilities. This allows you to use the Web camera to take digital photos that
you can use on your computer. For example, you can use a Web camera to
add pictures of yourself to an e-mail message you send or place photographs
on your Web page.

42

2.3

Ergonomics

Ergonomics is the science of fitting the job to the worker and adapting the work
environment to the needs of humans. An overall goal of ergonomics is to promote
health and safety and to optimize productivity.
It is often useful in performing a workstation analysis to start with the symptoms
experienced by the operator. Symptoms can give clues about the type of workstation
problems to look for. However, symptoms are often caused by a combination of
workstation problems, and multiple symptoms are common. Therefore, complete
workstation assessments are useful. It is also useful to get a clinical evaluation from an
expert in upper extremity disorders who emphasizes conservative (non-surgical)
treatment (such as at the ErgoCenter clinic) the combination of early clinical
intervention and ergonomic intervention has been shown to be very effective at
preventing chronic conditions.
To use these factsheets, find the symptoms that are present, find the possible
cause(s), and then look up the solutions for that cause in the next factsheet.
Finger pain/numbness in the thumb & first 2 fingers:
Can be from multiple sources (wrist to neck) caused by compression of the median
nerve: see wrist, elbow, and shoulder.
Wrist pain in dominant hand only:


Mouse position not close enough (mouse won't fit)



Wrist bent in mouse use



Wrist resting on sharp/hard edges



Left handed mouse in right hand, or vice versa



Keeping fingers tensed on mouse/ forceful hand grip



Fatigue (Not enough micro breaks)

43



Non-typing tasks requiring repeated/forceful grip, especially pinch grip



Poor typing technique

Wrist pain in both hands:


Wrists not neutral (bent up, down, left or right)



Fatigue (Not enough micro breaks)



Wrists resting on sharp/hard edges



Palms planted on desk or wrist rest while typing



Poor typing technique

Shoulder/Upper Back pain:


Mouse too far/high (if pain is on mousing side)



No elbow supports



Elbow supports too far apart or at wrong height



Desk or keyboard tray too high



Inadequate chair



Leaning forward towards monitor



Cradling phone between ear and shoulder



Stress



Poor typing technique

44

Neck pain:


Cradling phone between ear and shoulder



Monitor wrong height



Wearing bifocals (tipping head back to see monitor)



Leaning head forward (fatigue or monitor too hard to see)



Monitor to left or right of keyboard (twisted neck posture)



Typing from copy that is at angle to monitor (such as no copyholder)



Stress

Lower Back pain:



Non-adjustable lumbar support



No lumbar support



Chair too high (dangling feet pull back away from lumbar support)



Chair seat too long (seat front pressing behind knees pulls back away from
lumbar support)



Leaning forward in chair, away from lumbar support

Leg falling asleep/ discomfort:


Chair too high and no footrest to elevate legs



Pan depth of chair too long (presses into back of knee)



Sharp front edge of chair (inadequate padding)

45



Chair seat tips back too easily (front presses into back of legs)



Sitting with crossed legs



Wallet in back pocket

Eye strain/ headaches:


Improper eye glasses



Flicker or poor monitor



Font size or window size too small



Glare



Eyes too close or too far from monitor



Fatigue (Not enough micro breaks)



Environmental conditions (dryness, dust, etc.)



Stress

The following paragraphs provide a few guidelines for working conditions when using a
computer.
Chair: A well-designed chair with easy-to-implement adjustability is essential. A user
can vary angles of back support and the seat pan to control the degree of pressure on
the thighs and back. Weight should be evenly distributed, with no extreme pressure
points. An upright posture is a little easier to achieve if the seat pan is tilted slightly
forward of horizontal. When a person is seated, feet should rest on the floor and the
chair seat pan should be even with the back of the knee, ranging from 13 to 19 inches
above the floor depending on an individual's height. A foot rest may be used to relieve
pressure on the thighs. Both lumbar and mid-level back support is needed. Arm rests,
adjustable for height, are helpful to many people. The chair should have a five-point
base for stability and casters for easy movement.

46

Keyboard: The keyboard provides the primary means of interacting with a computer.
The keyboard should be in a comfortable position, and wrists should "float" over the
keyboard when keying with a light touch so wrists and forearms remain straight.
Although wrist pads are helpful for resting when not keying, they can actually create
problems when a user keeps wrists on them when keying because the wrists can bend
down. Different opinions exist on the appropriate angle of the keyboard; some people
prefer a flat position while others find a reverse incline more comfortable. Split and
curved key boards are available, too. However, the most important part of keyboard
use is keeping the wrists straight in line with the forearm and not bent to the side.
When voice-recognition technology be comes commonly used, dependency on the key
board will be reduced.
Mouse: A mouse should be positioned next to the keyboard, reachable without
extending the arm in an awkward position. Again, a light touch is needed and users
should avoid gripping or squeezing the mouse. A wrist support or adjustable mouse
platform may be helpful if a user begins to develop wrist problems. A variety of shapes
are available for these pointing devices, and a trackball can be used for the same
purpose.
Monitor: A monitor should be directly in front of the user, with the top of the screen at
or below the line of sight, 18 to 30 inches away from the eyes, and tilt able to avoid
glare from overhead lighting and windows. If necessary, antiglare filters can be added.
Screen size should be large enough for easy reading of screen character sizes with a
screen refresh rate fast enough to avoid a visible flicker. An individual can experience
blurred vision or fatigue from a poor monitor viewing angle, reflected glare, or a lowquality monitor. Because glands in the eyelids produce tears that cleanse eyes as the
eyelids blink and the eyes move, irritated eyes can develop because one's blink rate
tends to decrease when one is concentrating.

47

To avoid neck and eyestrain, an individual should do the following:


Use a copyholder positioned near the monitor to support material used with
computer work.



Use lower levels of lighting to reduce glare on monitors. Many older offices have
high illumination levels that are necessary for paper-intensive tasks—but are too
highly lighted for computer work. Softer overall, or ambient, lighting should be
used, with task lighting added to surfaces as needed for more illumination.



Relax eye muscles by shifting focus from the computer screen to distant objects for
a few seconds every 5 to 10 minutes.



Take micro breaks to stretch the neck, shoulders, hands, wrists, back, and legs as
well as to rest the eyes. Stretching exercises can be simple neck rotations,
shoulder shrugs; fists clenched and then released, or arms hanging down naturally
for a few moments. Get up and move around about every 30 minutes. Take a brisk
walk if possible. Exercises with hand weights will help with stretching and will give
the body isometric exercise.

While it may be ideal to have individually adjustable temperature controls, this is not
feasible in many work situations. For business offices, most people are comfortable
with temperature levels at 68 to 72 in the winter and 72 to 76 in the summer. Humidity
levels should be maintained between 40 to 60 percent not only for comfort but also for
proper functioning of office equipment. Indoor air quality involves more than heating
and cooling—air should be cleansed of pollutants (bacteria, dust, fumes, etc.), with
fresh air added before circulation. Many factors affect the efficiency of HVAC (heating,
ventilation, and air conditioning) systems. These systems must be designed for the
number of people and the equipment to be used in each area because computers and
other devices can produce almost as much heat as a human body produces.
Another important concept is adjustability of work pace. Jobs may require redesign to
allow workers to accomplish tasks at varying speeds or to enable workers to rotate to
different tasks or to use a variety of work methods that permit different movements.
Rest breaks are important, too, and micro breaks can be taken to interrupt in tense
situations, to rest arms and wrists, or to rest eyes.

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Much ergonomics information is available in print and on the Internet, published by
organizations such as the Occupational Safety and Health Administration (OSHA), the
National Institute of Occupational Safety and Health (NIOSH), the National Safety
Council, the Human Factors and Ergonomic Society, and others. OSHA is developing
ergonomics program standards that were to be published in 2000 (OSHA 1999).
Consultants can provide technical expertise to help with all phases of ergonomics
assessment and the implementation of corrective measures and/or training programs.

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3

Database Systems

A database program helps you manage large collections of information. Database
programs are commonly used to manage mailing lists, phone directions, product
listings and payroll information. Commonly used database programs include Microsoft
Access, Corel Paradox and FileMaker Pro.

A table is a collection of information about a specific topic, such as a mailing list. You
can have one or more table in a database. A table consists of fields and records. A
field is a specific category of information in a table. For example, a field can contain
the first names of all your clients. A record is a collection of information about one
person, place or thing in a table. For example, a record can contain the name and
address of one client.

A database stores and manages a collection of information related to a particular
subject or purpose. You can efficiently add, update, view and organize the information
stored in a database. Database programs provide forms you can use to quickly change
the information stored in a table.

You can instantly locate information of interest in a database. For example, you can
find all clients with the last name Smith. You can also perform more advanced
searches, called queries. When you create a query, you ask a database program to
find information that meets certain criteria, or conditions. For examples, you can find all
the clients living in California who purchased more than $100 of supplies last year.

You can perform calculations on the information in a database to help you make
accurate and informed decisions. You can neatly present the information in
professionally designed reports.

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3.1 Database Management Systems
Database Management System (DBMS) is a set of computer programs that controls
the creation, maintenance, and the use of the database of an organization and its end
users. It allows organizations to place control of organization-wide database
development in the hands of database administrators (DBAs) and other specialists.
DBMSes may use any of a variety of database models, such as the network model or
relational model. In large systems, a DBMS allows users and other software to store
and retrieve data in a structured way. It helps to specify the logical organization for a
database and access and use the information within a database. It provides facilities
for controlling data access, enforcing data integrity managing concurrency controlled,
restoring database.

Examples of Database Management Systems:


Adabas



Microsoft Visual FoxPro



Adaptive Server Enterprise



MonetDB



Alpha Five



MySQL



Computhink's ViewWise



OpenLink Virtuoso



CSQL



OpenOffice.org Base



Daffodil DB



Oracle Database



DataEase



ParAccel



FileMaker



PostgreSQL



Firebird



Progress



Glom



SQL Anywhere



IBM DB2



SQLite



IBM UniVerse



Teradata



Ingres



Unisys OS 2200 databases



Informix





InterSystems Caché





Kexi



WX2

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Vertica Analytic Database



Linter SQL RDBMS



Lotus Approach



Mark Logic



Microsoft Access



Microsoft SQL Server

Components of DBMS:


DBMS Engine accepts logical request from the various other DBMS
subsystems, converts them into physical equivalent, and actually accesses the
database and data dictionary as they exist on a storage device.



Data Definition Subsystem helps user to create and maintain the data
dictionary and define the structure of the files in a database.



Data Manipulation Subsystem helps user to add, change, and delete
information in a database and query it for valuable information. Software tools
within the data manipulation subsystem are most often the primary interface
between user and the information contained in a database. It allows user to
specify its logical information requirements.



Application Generation Subsystem contains facilities to help users to develop
transactions-intensive applications. It usually requires that user perform a
detailed series of tasks to process a transaction. It facilities easy-to-use data
entry screens, programming languages, and interfaces.



Data Administration Subsystem helps users to manage the overall database
environment by providing facilities for backup and recovery, security
management, query optimization, concurrency control, and change
management.

3.2 Hierarchical Database
A hierarchical data model is a data model in which the data is organized into a tree-like
structure. The structure allows repeating information using parent/child relationships:

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each parent can have many children but each child only has one parent. All attributes
of a specific record are listed under an entity type.

Fig. 10

Example of a Hierarchical Model
In a database, an entity type is the equivalent of a table; each individual record is
represented as a row and an attribute as a column. Entity types are related to each
other using 1: N mapping, also known as one-to-many relationships.
The most recognized and used hierarchical database is IMS developed by IBM.
An example of a hierarchical data model would be if an organization had records of
employees in a table (entity type) called "Employees". In the table there would be
attributes/columns such as First Name, Last Name, Job Name and Wage. The
company also has data about the employee’s children in a separate table called
"Children" with attributes such as First Name, Last Name, and date of birth. The
Employee table represents a parent segment and the Children table represents a Child
segment. These two segments form a hierarchy where an employee may have many
children, but each child may only have one parent.

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Consider the following structure:

EmpNo

Designation

ReportsTo

10

Director

20

Senior Manager 10

30

Typist

20

40

Programmer

20

Fig. 11

In this, the "child" is the same type as the "parent". The hierarchy stating EmpNo 10 is
boss of 20, and 30 and 40 each report to 20 is represented by the "ReportsTo"
column. In Relational database terms, the ReportsTo column is a foreign key
referencing the EmpNo column. If the "child" data type were different, it would be in a
different table, but there would still be a foreign key referencing the EmpNo column of
the employees table.
This simple model is commonly known as the adjacency list model, and was
introduced by Dr. Edgar F. Codd after initial criticisms surfaced that the relational
model could not model hierarchical data.

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3.3 Network Database
The network model is a database model conceived as a flexible way of representing
objects and their relationships.

Fig. 12

Example of a Network Model
The network model's original inventor was Charles Bachman, and it was developed
into a standard specification published in 1969 by the CODASYL Consortium.
Where the hierarchical model structures data as a tree of records, with each record
having one parent record and many children, the network model allows each record to
have multiple parent and child records, forming a lattice structure.
The chief argument in favour of the network model, in comparison to the hierarchic
model, was that it allowed a more natural modeling of relationships between entities.
Although the model was widely implemented and used, it failed to become dominant
for two main reasons. Firstly, IBM chose to stick to the hierarchical model with seminetwork extensions in their established products such as IMS and DL/I. Secondly, it
was eventually displaced by the relational model, which offered a higher-level, more

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declarative interface. Until the early 1980s the performance benefits of the low-level
navigational interfaces offered by hierarchical and network databases were persuasive
for many large-scale applications, but as hardware became faster, the extra
productivity and flexibility of the relational model led to the gradual obsolescence of the
network model in corporate enterprise usage.

Some Well-known Network Databases:


Digital Equipment Corporation DBMS-10



Digital Equipment Corporation DBMS-20



Digital Equipment Corporation VAX DBMS



Honeywell IDS (Integrated Data Store)



IDMS (Integrated Database Management System)



Oracle CODASYL DBMS



Raima Data Manager (RDM) Embedded



RDM Server



Turbo IMAGE



Univac DMS-1100

3.4

Relational Database

The relational model for database management is a database model based on firstorder predicate logic, first formulated and proposed in 1969 by E.F. Codd

56

Fig. 13
Its core idea is to describe a database as a collection of predicates over a finite set of
predicate variables, describing constraints on the possible values and combinations of
values. The content of the database at any given time is a finite (logical) model of the
database, i.e. a set of relations, one per predicate variable, such that all predicates are
satisfied. A request for information from the database (a database query) is also a
predicate.

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Relational model concepts:

In the relational model, related records are linked together with a "key".
The purpose of the relational model is to provide a declarative method for specifying
data and queries: we directly state what information the database contains and what
information we want from it, and let the database management system software take
care of describing data structures for storing the data and retrieval procedures for
getting queries answered.
IBM's original implementation of Codd's ideas was System R. There have been
several commercial and open source products based on Codd's ideas, including IBM's
DB2, Oracle Database, Microsoft SQL Server, PostgreSQL, MySQL, and many others.
Most of these use the SQL data definition and query language. A table in an SQL
database schema corresponds to a predicate variable; the contents of a table to a
relation; key constraints, other constraints, and SQL queries correspond to predicates.
However, it must be noted that SQL databases, including DB2, deviate from the
relational model in many details; Codd fiercely argued against deviations that
compromise the original principles.

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Alternatives to the relational model:
Other models are the hierarchical model and network model. Some systems using
these older architectures are still in use today in data centers with high data volume
needs or where existing systems are so complex and abstract it would be cost
prohibitive to migrate to systems employing the relational model; also of note are
newer object-oriented databases.
A recent development is the Object-Relation type-Object model, which is based on the
assumption that any fact can be expressed in the form of one or more binary
relationships. The model is used in Object Role Modeling (ORM), RDF/Notation 3 (N3)
and in Gellish English
The relational model was the first database model to be described in formal
mathematical terms. Hierarchical and network databases existed before relational
databases, but their specifications were relatively informal. After the relational model
was defined, there were many attempts to compare and contrast the different models,
and this led to the emergence of more rigorous descriptions of the earlier models;
though the procedural nature of the data manipulation interfaces for hierarchical and
network databases limited the scope for formalization.
Implementation:
There have been several attempts to produce a true implementation of the relational
database model as originally defined by Codd and explained by Date, Darwen and
others, but none have been popular successes so far. Rel is one of the more recent
attempts to do this.

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3.5

Object Oriented Database

An object database (also object-oriented database) is a database model in which
information is represented in the form of objects as used in object-oriented
programming.

Example of an object-oriented model:
Object databases are a niche field within the broader DBMS market dominated by
Relational database management systems (RDBMS). Object databases have been
considered since the early 1980s and 1990s but they have made little impact on
mainstream commercial data processing, though there is some usage in specialized
areas.
Adoption of object databases:
Object databases based on persistent programming acquired a niche in application
areas such as engineering and spatial databases, telecommunications, and scientific
areas such as high energy physics and molecular biology. They have made little
impact on mainstream commercial data processing, though there is some usage in
specialized areas of financial services. It is also worth noting that object databases
held the record for the World's largest database (being the first to hold over 1000
terabytes at Stanford Linear Accelerator Center) and the highest ingest rate ever
recorded for a commercial database at over one Terabyte per hour.

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Another group of object databases focuses on embedded use in devices, packaged
software, and real-time systems.
Technical features:
Most object databases also offer some kind of query language, allowing objects to be
found by a more declarative programming approach. It is in the area of object query
languages, and the integration of the query and navigational interfaces, that the
biggest differences between products are found. An attempt at standardization was
made by the ODMG with the Object Query Language, OQL.
Access to data can be faster because joins are often not needed (as in a tabular
implementation of a relational database). This is because an object can be retrieved
directly without a search, by following pointers. (It could, however, be argued that
"joining" is a higher-level abstraction of pointer following.)
Another area of variation between products is in the way that the schema of a
database is defined. A general characteristic, however, is that the programming
language and the database schema use the same type definitions.
Multimedia applications are facilitated because the class methods associated with the
data is responsible for its correct interpretation.
Many object databases, for example VOSS, offer support for versioning. An object can
be viewed as the set of all its versions. Also, object versions can be treated as objects
in their own right. Some object databases also provide systematic support for triggers
and constraints which are the basis of active databases.
Advantages and disadvantages:
The main benefit of creating a database with objects as data is speed. OODBMS are
faster than relational DBMS because data isn’t stored in relational rows and columns
but as objects]. Objects have a many to many relationship and are accessed by the
use of pointers. Pointers are linked to objects to establish relationships. Another
benefit of OODBMS is that it can be programmed with small procedural differences
without affecting the entire system]. This is most helpful for those organizations that

61

have data relationships that aren’t entirely clear or need to change these relations to
satisfy the new business requirements. This ability to change relationships leads to
another benefit which is that relational DBMS can’t handle complex data models while
OODBMS can.
Benchmarks between ODBMSs and RDBMSs have shown that an ODBMS can be
clearly superior for certain kinds of tasks. The main reason for this is that many
operations are performed using navigational rather than declarative interfaces, and
navigational access to data is usually implemented very efficiently by following
pointers.
Critics of navigational database-based technologies like ODBMS suggest that pointerbased techniques are optimized for very specific "search routes" or viewpoints; for
general-purpose queries on the same information, pointer-based techniques will tend
to be slower and more difficult to formulate than relational. Thus, navigation appears to
simplify specific known uses at the expense of general, unforeseen, and varied future
uses. However, with suitable language support, direct object references may be
maintained in addition to normalized, indexed aggregations, allowing both kinds of
access; furthermore, a persistent language may index aggregations on whatever its
content elements return from a call to some arbitrary object access method, rather
than only on attribute value, which allows a query to 'drill down' into complex data
structures.
Other things that work against ODBMS seem to be the lack of interoperability with a
great number of tools/features that are taken for granted in the SQL world, including
but not limited to industry standard connectivity, reporting tools, OLAP tools, and
backup and recovery standards.[ Additionally, object databases lack a formal
mathematical foundation, unlike the relational model, and this in turn leads to
weaknesses in their query support. However, this objection is offset by the fact that
some ODBMSs fully support SQL in addition to navigational access, e.g.
Objectivity/SQL++, Matisse, and InterSystems CACHÉ. Effective use may require
compromises to keep both paradigms in sync.
In fact there is an intrinsic tension between the notion of encapsulation, which hides
data and makes it available only through a published set of interface methods, and the

62

assumption underlying much database technology, which is that data should be
accessible to queries based on data content rather than predefined access paths.
Database-centric thinking tends to view the world through a declarative and attributedriven viewpoint, while OOP tends to view the world through a behavioral viewpoint,
maintaining entity-identity independently of changing attributes. This is one of the
many impedance mismatch issues surrounding OOP and databases.
Although some commentators have written off object database technology as a failure,
the essential arguments in its favor remain valid, and attempts to integrate database
functionality more closely into object programming languages continue in both the
research and the industrial communities.

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4

System Software
4.1

The Operating System

Introduction to Operating Systems:

All desktop computers have operating systems and many computer users interact with
these operating systems on a daily basis without even realizing it. This is because
operating systems make their functions run so smoothly that it makes them mostly
invisible to the user. An operating system is what controls and coordinates the use of
the computer hardware among the application programs, or software, for the user.
Without an operating system, complex computers would be a useless heap of metal.

Not all computers have operating systems. For example, the computers that control
the remote control for your television or the microwave oven in your kitchen do not
need an operating system to function. They are simple computers that have one set of
functions to perform, so they only need to run one hard-wired program. An operating
system would be unnecessary and would make these devises more complex and
expensive.

Operating systems are made out of portable codes, which enable the user to change
or modify the operating system without having to scrap the device altogether. Because
of this, desktop computer users can add new applications, updates, or even a
completely new operating system. If operating systems were made out of permanent
physical circuits, then the user would have to buy another device if they wanted to
change how their device worked.

Operating systems have five main functions: 1) processor management, 2) memory
storage and management, 3) device management, 4) application interface, and 5) user
interface. These functions are the core of roughly all operating systems and are
located in the kernel of the operating system.

Processor management makes sure each process and application obtains enough
time from the processor to function correctly and that the computer uses as many

64

processor cycles as possible. Processes are sometimes confused with applications.
Applications are a process, but the application can make other processes start. Also,
applications can always bee seen by the user and a process can be invisible.

A user, application or the operating system can control a process. The operating
system controls processes and plans for them to be carried out by the CPU. Many
processes need an input before they actually use up CPU time. When it has no input,
the process is considered to be "suspended."

The CPU can only handle one operation at a time, but operating systems give the
illusion that many operations are happening at once. This is done by switching
between the various processes thousands of times per second. Processes are stored
in the RAM and use registers, stacks, and queues provided by the CPU. The operating
system allows a program to have a set number of CPU execution cycles when two
processes are multi-tasking. After the cycles are completed, the operating system
copies everything used by the process and bookmarks where the process was
paused. After one program's cycles are completed, the next cycle is loaded and starts
cycling where it was paused previously. This continues to happen until all of the
processes are completed.

The kernel is the essential part of the operating system. It allows the user to directly
interface with the computer through input/output devices and provides basic services
for the other parts of the operating system. Usually, a kernel has something called an
"interrupt handler" which deals with requests or completed I/O operations that vie for
the Kernel's resources, a scheduler that sets up which program gets operating time
and in what order, and then a supervisor that gives use of the computer to each
process when its turn arrives on the scheduler. Sometimes a manager is included that
manages the address space of the operating system in memory, sharing these among
all of the user's and components of the operating system. The kernel's services are
requested from application programs through a set of program interfaces known as
system calls. The kernel is being constantly used, and as such it needs to be loaded
up in memory in such a place that it won’t be bumped down from a program that is
used less frequently.

65

There are two broad tasks performed by the memory management. Every process
must have enough memory to perform and processes must not run into each other and
the memory must be used correctly so each process runs effectively. In order to avoid
collisions between processes, the operating system has to set up memory boundaries
for the software and applications.

The operating system and drivers are loaded onto the memory first. After they have
been loaded, the rest of the memory is divided amongst the applications and
processes. Applications and processes are loaded onto the memory in fixed block
sizes, which are established by the specific operating system. The fixed block sizes
start and end on boundaries which are determined by words of four or eight bytes.

The operating system goes through a driver to communicate with the external
hardware. Drivers translate the electrical signals from the hardware into the
programming languages of the application programs and operating system. Drivers are
separate from the operating system, which enables them to add new functions without
disturbing the operating system itself.

One of the main functions of an operating system is to manage all of the equipment of
the computer. For real-time operating systems, this is all of the functionality that is
needed. Providing a simple uniform way for users and applications to use the
hardware is important for the other operating systems.

APIs, application program interfaces, supply a uniform way for applications to
communicate with the functions of the computer. This allows programmers to run the
operating system and other computer functions without knowing the inside and out of
the CPU's operations. They do no have to worry about instruction codes, data types,
or response codes for tape drives and hard disks.

The UI, or user interface, allows the user to run the computer with little difficulty. The
UI is a program, or programs, that act as a communication device between the user
and the computer's functions. GUIs, graphical user interfaces, are the most popular
type of user interfaces.

66

MS-DOS:

MS-DOS (Microsoft Disk Operating System) is an operating system that performs
tasks using text commands you enter. DOS, as with any operating system, controls
computer activity. It manages operations such as data flow, display, data entry
amongst other various elements that make up a system. It was initially developed for
16-bit Intel processors and shipped with the first IBM PCs, and until the introduction of
Microsoft Windows.

Like folders in a filing cabinet MS-DOS uses directories to organize data stored on a
computer. The root directory (C:\) is the main directory. All the other directories are
located within this directory.

The role of DOS is to interpret commands the user enters via the keyboard. These
commands allow the following tasks to be executed:


file and folder management



disk upgrades



hardware configuration



memory optimization



program execution

These commands are typed after the prompt and in the case of MS-DOS the drive
letter followed by a backslash, for example: A:\ or C:\

To execute a command, type the command and then hit ENTER. For example, the
DATE command tells the computer to display the current date (C:\DATE).

Windows 3.1:

The first version of Microsoft Windows (Microsoft Windows 1.0) came out in November
1985. It had a graphical user interface, inspired by the user interface of the Apple

67

computers of the time. Windows 1.0 was not successful with the public, and Microsoft
Windows 2.0, launched December 9, 1987, did not do much better.
It was on May 22, 1990 that Microsoft Windows became a success, with Windows 3.0,
then Windows 3.1 in 1992, and finally Microsoft Windows for Workgroups, later
renamed Windows 3.11, which included network capabilities. Windows 3.1 cannot be
considered an entirely separate operating system because it was only a graphical user
interface running on top of MS-DOS.

In Widows 3.1, you use a mouse to navigate the screen and choose icons to perform
tasks. An icon is a small picture on the screen that represents an item on the
computer. A program icon allows you to start a program, such as a word processor. A
group icon contains and groups similar icons. Windows 3.1 uses windows, or small
rectangles, to display icons on the screen.

Windows 3.1’s File Manager allows you to view and organize all the files stored on
your computer. It uses directories to organize information, just as you would use
folders to organize papers in a filing cabinet.

Windows 95, 98 and Me:

On August 24, 1995, Microsoft launched the operating system Microsoft Windows 95.
Windows 95 signified Microsoft's willingness to transfer some of MS-DOS's capabilities
into Windows, but this new version was based more heavily on 16-bit DOS and
retained the limitations of the FAT16 (file allocation table) file system, so that it was not
possible to use long file names.

After minor revisions of Microsoft Windows 95, named Windows 95A OSR1, Windows
95B OSR2, Windows 95B OSR2.1 and Windows 95C OSR2.5, Microsoft released the
next version of Windows on June 25, 1998: Windows 98. Windows 98 natively
supported features other than those of MS-DOS but was still based upon it. What's
more, Windows 98 suffered from poor memory handling when multiple applications
were running, which could cause system malfunctions. A second edition of Windows

68

98 came out on February 17, 2000; it was named Windows 98 SE (for "Second
Edition").

On September 14, 2000, Microsoft released Windows Me (for Millennium Edition), also
called Windows Millennium. Windows Millennium was based largely on Windows 98
(and therefore on MS-DOS), but added additional multimedia and software
capabilities. Furthermore, Windows Millennium included a system-restore mechanism
for returning to a previous state in the event of a crash.

Windows 95 introduced an enhanced desktop, which is the background area of the
screen. You can save files and folders on the desktop or place shortcut on the desktop
for easy access. A shortcut provides a quick way to open a document or program you
use regularly. Windows 95 also provides a taskbar at the bottom of the desktop. The
taskbar contains the Start button, which lets you quickly access programs and
documents, and displays the name of each open window on the screen.

Windows 98 and Windows 98 SE includes several programs that allow you to view and
exchange information on the Internet, including Internet Explorer and Outlook Express.
Internet Explorer lets you browse though information on the Web, while Outlook
Express lets you exchange electronic mail with people around the world.

FAT32 is the file system that better manages data on large hard drives to reduce
wasted space. Windows 98 can convert your hard drive to FAT32 without disrupting
the programs and documents currently on your computer.

Windows ME allows you to record, edit and save videos on your computer using
Windows Movie Maker. Windows ME also includes a version of Windows Media
Player, which helps you manage your multimedia files and allows you to listen to radio
stations over the internet

If you are experiencing problems with your computer, Windows ME includes a System
Restore feature which allows you to return your computer to a time before the
problems occurred. For example, if you have accidentally deleted program files, you
can restore your computer to a time before you deleted the files.

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Windows NT:

Windows NT is a powerful version of the Windows operating system that provides
advanced networking and security features. Windows NT's outward appearance
makes it look a lot like Windows 95/98/Millennium, but Windows NT has a separately
developed kernel. Because of this, Windows NT has the following characteristics:


Windows NT is a pre-emptive multitasking system;



Windows NT is a multi-user system, which means that depending on the user who
is connected to the system, the interface might be different, as might system
privileges;



Windows NT natively supports numerous network features;



Windows NT has more security, in particular for the file system (NTFS which
stands for New Technology File System) as well as for the robustness of the OS.

Since Windows NT manages users, the network administrator (who holds all special
privileges on the system) is able to control privileges for each user connected to the
system. What's more, with the NTFS file system, which includes the capability to
assign ownership for a file, each user or user group can be assigned specific access
privileges for different system files.

Windows 2000 and Windows XP:

On February 17, 2000, the next version of NT 4.0 was renamed Windows 2000
(instead of Windows NT 5.0) in order to highlight the unification of "NT" with the
"Windows 9x" systems. Windows 2000 is an entirely 32-bit system with characteristics
of Windows NT, as well as an improved task manager and full compatibility with USB
and FireWire peripherals. Then, on October 25, 2001, Windows XP arrived on the
scene. This was a merger of the preceding operating systems. Finally, on April 24,
2003, a server operating system was released by Microsoft: Windows Server 2003.

70

Windows 2000 Professional is commonly used on client/server networks but can also
be used on peer-to-peer networks. This operating system offers increased stability and
provides tools that can help you maintain your computer. Windows 20000 Professional
is intended for business use.

The original versions of Windows 2000 for large client/server networks – Windows
2000 Server and Windows 2000 Advanced Server – have been replaced by Windows
Server 2003. This powerful operating system is designed to support the heavy
networking processing demands of medium to large businesses and Internet service
providers.

Unix:

Unix is the basis for which Linux and Macintosh were started and is a multi-user
operating system. Unix is entirely command line based and does not offer a nice GUI
as opposed to Windows, Linux or Mac. Although it can be set up to run on a desktop
or laptop computer, it usually runs on large main frames, such as supercomputers. The
command line allow for a flexible, reliable, secure, and powerful computer. This is why
it is used in mainframes that manage data for large corporations, governments, and
financial institutions.

Unix was created in 1969, by Ken Thompson and Dennis Ritchie. It was soon rewritten
in C language, which made it portable and changed the history of operating systems
forever. When Unix was first written, developers believed operating systems had to be
written in the assembly language so that they functioned and would be able to use the
hardware. The first version of Unix available out side of Bell Labs was Version 6.

Unix incorporates networking, which makes it ideal for internet connection. With other
operating systems a user needed to buy additional software for networking. Unix was
developed by many different people so it is very flexible. Unix is an open system and
some of the versions are free.

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Linux:

Linus Torvalds' interest in Minix, a small UNIX system, sparked his idea of creating an
operating system called Linux. He wanted to create a system that would exceed the
Minix standards. In 1991, he released his first version, version 0.02. Three years later,
he released version 1.0 of the Linux Kernel. The Kernel source code was and is
available to the general public at no cost.

The functionality and adaptability of Linux has made it a great alternative for both UNIX
and Windows. Linux is primarily used as a server platform. At first, tech pundits
believed Linux to be unsuitable for the general public's computing needs. But because
of the efforts of developers of desktop management systems, now there are many
applications that run on Linux.
Unlike Unix, Linux includes many GUIs like KDE and GNOME. Linux used to have a
few drawbacks that included compatibility with hardware because of the lack of
support from manufacturers. Linux has gained more support and is now more
compatible with hardware. It has gained more support and popularity because of the
highly customizable GUI.

Mac OS X:

Mac OS X is the latest version of the Macintosh operating system developed,
marketed and sold by Apple. It is a successor to Mac OS 9 and has been included in
all new Macintosh computer systems since 2002. There are currently several versions
of Mac OS X including Mac OS X Leopard, Mac OS X Jaguar and Mac OS X Panther.

Mac OS X offers an improved operating system core, or kernel, over previous Mac OS
versions. This improved kernel helps ensure your computer hardware and software
work together efficiently and provides more stability than previous versions. Mac OS X
is designed to take advantage of multiple CPUs, or processors, in a computer. If your
computer has more than one CPU, Mac OS X will run faster, with even more stability.
Mac OS X offers a new GUI that is designed to make operating systems easier to use
than previous versions. The new GUI features photo-quality icons and an area at the

72

bottom of the screen, called the Dock, where you can store items, such as folders and
programs that you frequently access.

Mac OS X combines several advanced graphics technologies, including Portable
Document Format (PDF), QuickTime and OpenGL, to provide enhanced graphics
capabilities. This improves the display of graphics in programs such as desktop
publishing and games.

4.2

CPU Management

The system unit is the central component of all computers as it contains the brains and
the memory of the computer and the disk drives where data is stored. It usually comes
in the shape of a big box (tower or mini-tower) that houses the disk drives and the
back of it is typically covered with different types of connectors. Some PCs put some of
those connectors on the front of the case (in addition to the back) to make it easier to
connect to portable devices such as an IPod music player or a digital video camcorder.

If you were to open the case on your system unit, you would see all sorts of computer
chips and circuit boards. The really big board located at the base of the computer (to
which everything is plugged into) is called the motherboard, because it carries the
microprocessor and memory chips, as well as other internal components that enable
the system to function. Most PC motherboards contain six or more slots for add-on
cards such as a video card to transmit video signals to the monitor. Here is an
example of a motherboard with common components referenced:

73

Fig. 14a

74

Buried somewhere on the motherboard is the CPU. It processes all the instructions
necessary for your computer to perform its duties. That is, the CPU processes
instructions, performs calculations and manages the flow of information through the
computer system.

Fig. 14b

The more powerful the microprocessor chip is, the faster and more efficiently your
system runs. Every input and output device hooked up to a computer (e.g. monitor,
keyboard, printer, etc) either issues or receives instructions that the microprocessor
then processes. Your software programs also issue instructions that must be
implemented by the microprocessor. This chip is the workhorse of the computer
system as it affects just about everything your computer does.

Different computers have different types of microprocessor chips. Many IBM
compatible computers use chips manufactured by Intel. Some use Intel-compatible
chips manufactured by AMD (Sempron and Athlon processors) and other firms but all
IBM-compatible computers that run the Windows operating system use Intelcompatible chips. Intel is also the largest manufacturer of CPUs (Pentium and Celeron
processors).

75

In addition to having different chip manufacturers, microprocessors also run at different
speeds measured in cycles per second (or gigahertz GHz), where a cycle represents a
single task performed by the CPU such as adding two numbers. A CPU with a speed
of 1 GHz can run at one billion clock ticks per second! The larger the gigahertz number
the faster the chip runs.

The elements in a CPU are measured in microscopic units called microns or
nanometers (nm). Today, elements in a CPU can be less than 0.13 microns or 100
nanometers wide. Smaller CPU elements are better because more elements can fit on
a CPU which translates into faster speed with which the CPU can process information.
Many computer manufacturers are moving toward a dual-core design for CPUs which
allows a computer to use two processors within a single CPU. This substantially
improves the speed and power of a computer.

76

4.3

File Management

A file manager or file browser is a computer program that provides a user interface to
work with file systems. The most common operations used are create, open, edit,
view, print, play, rename, move, copy, delete, attributes, properties, search/find, and
permissions. Files are typically displayed in a hierarchy. Some file managers contain
features inspired by web browsers, including forward and back navigational buttons.
Some file managers provide network connectivity such as FTP, NFS, SMB or
WebDAV. This is achieved either by allowing the user to browse for a file server,
connect to it and access the server's file system like a local file system, or by providing
its own full client implementations for file server protocols.
Orthodox file managers:
Orthodox file managers or "Commander-like" file managers have three windows (two
panels and one command line window).
Orthodox file managers are one of the older families of file managers. They develop
and further extend the interface introduced by John Socha's famous Norton
Commander for DOS. The concept is more than twenty years old as Norton
Commander version 1.0 was released in 1986. Despite their age they are actively
developed and dozens of implementations exist for DOS, Unix and Microsoft Windows.
A public standard (version 1.2 dated June 1997) is available from Nikolai Bezroukov's
website.
Features:
The following features define the class of orthodox file managers.


They present the user with a two-panel directory view consisting of one active and
one passive panel. The latter always serves as a target for file operations. Panels
are shrinkable and if shrunk they expose the terminal window hidden behind them.
Normally only the last line of the terminal window (the command line) is visible.



They provide close integration with an underlying OS shell via command line and
associated terminal window that permits viewing the results of executing the shell

77

command entered on the command line (e.g., via Ctrl-O shortcut in Norton
Commander).


They provide the user with extensive keyboard shortcuts.



The file manager can be used without or with minimal use of the mouse.



Users can create their own file associations and scripts that are invoked for certain
file types and organize these scripts into a hierarchical tree (e.g., as a user script
library or user menu



Users can extend the functionality of the manager via so called User menu or Start
menu and extensions menu. Norton Commander introduced the concept of userdefined file associations that is now used in all modern

Other common features include:


Information on the "active" and "passive" panels may be used for constructing
commands on the command line. Examples include current file, path to left panel,
path to right panel, etc.



They provide a built-in viewer for (at least) the most basic file types.



They have a built-in editor. In many cases, the editor can extract certain elements
of the panels into the text being edited.



Many support virtual file systems (VFS) such as viewing compressed archives, or
via an FTP connection.



They often have the word commander in the name.

An orthodox file manager typically has three windows. Two of the windows are called
panels and are symmetrically positioned at the top of the screen. The third is the
command line which is essentially a minimized command (shell) window that can be
expanded to full screen. Only one of the panels is active at a given time. The active
panel contains the "file cursor". Panels are resizable. Each panel can be hidden. Files
in the active panel serve as the source of file operations performed by the manager.
For example, files can be copied or moved to the passive panel. This gives the user
the ability to use only the keyboard with the convenience of the mouse interface. The
active panel shows information about the current working directory and the files that it
contains. The passive (inactive) panel shows the content of the same or other directory

78

(the default target for file operations). Users may customize the display of columns that
show relevant file information. The active panel and passive panel can be switched
(often by pressing the tab key). Other user interface elements include:
1. Path: shows the source/destination location of the directory in use
2. Information about directory size, disk usage and disk name (usually at the
bottom of the panels)
3. Panel with information about file name, extension, date and time of creation,
last modification, permissions (attributes) and other
4. Info panel with number of files in directory, sum of size of selected files.
5. Tabbed interface (usually GUI file managers)
6. Function keys: F1–F10 has all the same functions under all orthodox file
managers. Examples: F5 always copies file(s) from the active to the inactive
panel, while F6 moves the file.
7. The introduction of tabbed panels in some file managers (for example Total
Commander) made it possible to manipulate more than one active and passive
directory at a time.
Orthodox file managers are among the most portable file managers. Examples are
available on almost any platform both with command-line interface and graphical user
interface. This is the only type of command line managers that have a published
standard of the interface (and actively supported by developers). This makes possible
to do the same work on different platforms without much relearning of the interface.
Sometimes they are called dual-pane managers, a term that is typically used for
programs such as the Windows File Explorer (see below). It is technically incorrect
since they have three windows including a command line window below (or hidden
behind) two symmetric panels. Command line windows play a very prominent role in
the functionality of this type of file manager. Furthermore, most of these programs
allow using just one pane with the second one hidden.
Focusing on 'dual panes' may be misleading; it is the combination of all of these
features which is important.

79

In summary, a chief distinguishing feature is the presence of the command line window
and direct access to shell via this window - not the presence of two symmetric panes
which is relatively superficial
Examples:
Notable examples include:


Altap Salamander



File Commander



PathMinder



Demos Commander



FreeCommander



SE-Explorer



Directory Opus



Krusader



Total Commander



Dos Navigator



Midnight Commander



Volkov Commander



Double Commander



muCommander



WinSCP



FAR Manager



Norton Commander



ZTreeWin

Navigational file manager:
A navigational file manager, also called an Explorer type manager, is a newer type of
file manager which became prominent because of its integration in Microsoft Windows.
The Windows Explorer is a classic representative of the type, using a "navigational"
metaphor to represent file system locations. Since the advent of GUIs it has become
the dominant type of file manager for desktop computers, being used, for example, in
all Microsoft Windows products.
Typically it has two panes, with the file system tree in the left pane and the current
directory in the right one. For Mac OS X, one view in the Finder is an example of a
navigational file manager.

80

Fig. 15

The Miller Column browser from GNUstep is a type of Navigational file manager.

Concepts:


The window displays the location currently being viewed.



The location being viewed (the current directory) can be changed by the user,
by opening folders, pressing a back button, typing a location, or using
additional pane with the navigation tree representing part or all the filesystem.



Icons represent files, programs, and directories.

The interface in a navigational file manager often resembles a web browser, complete
with back, forward buttons that work with history, and maybe even reload buttons.
Sometimes there is also an address bar where the file or directory path (or URI) can
be typed.
Moving from one location to another need not open a new window. At the same time
several file manager instances can be opened, and they can communicate with each
other via drag-and-drop and clipboard operations, so it is possible to view several
directories simultaneously and perform cut-and paste operations between instances.
Most navigational managers have two panes with the left pane a tree view of the
filesystem. The latter serves as the most common instrument for filesystem navigation.
This means that unlike orthodox managers, the two panes are asymmetrical: the first

81

(usually left) provides the tree view of filesystem and the second (usually right) file
view of the current directory.
When a directory of the tree is selected it becomes current and the content of the
second (right) pane changes' to the files in the current directory.
File operations are based on drag-and-drop and editor metaphors: users can select
and copy files or directories into the clipboard and then paste them in a different place
in the filesystem or even in a different instance of file manager.

4.4

Spatial file manager

Spatial file managers use a spatial metaphor to represent files and folders as if they
were real physical objects. A spatial file manager imitates the way people interact with
physical objects.
Some ideas behind the concept of a spatial file manager are:
1. A single window represents each opened folder.
2. Each window is unambiguously and irrevocably tied to a particular folder.
3. Stability: files, folders, and windows go where the user moves them, stay where
the user puts them ("preserve their spatial state"), and retain all their other
"physical" characteristics (such as size, shape, color and location).
4. The same item can only be viewed in one window at a time.
As in navigational managers, when a folder is opened, the icon representing the folder
changes—perhaps from an image showing a closed drawer to an opened one,
perhaps the folder's icon turns into a silhouette filled with a pattern—and a new
window is opened.

82

Fig. 17

4.5

Task Management

Task management is the process of managing a task (or task portfolio) through its life
cycle, including planning, testing, tracking and reporting. Task management can help
either individuals achieve goals, or groups of individuals collaborate and share
knowledge for the accomplishment of collective goals. Tasks also differentiate by
complexity, from low to high
Effective task management supposes managing all aspects of a task, including its
status, priority, time, human and financial resources assignments, recurrency,
notifications and so on. These can be lumped together broadly into the basic activities
of task management.

83

Managing multiple individual or team tasks may require a special task management
software which is available on the Web. Specific software dimensions support common
task management activities. These dimensions exist across software products and
services and fit different task management initiatives in myriad ways. In fact, many
people believe that task management should serve as a foundation for project
management activities.
Task Management Software:
Task management software tools abound in the marketplace. Some are free; others
exist for enterprise-wide deployment purposes. Some boast enterprise-wide task
creation, visualization and notifications capabilities - among others - scalable to small,
medium and Fortune 100 size companies, from individual projects to ongoing
corporate task management.
Project management and calendaring software also often provide task management
software with advanced support for task management activities and corresponding
software environment dimensions, reciprocating the myriad project and performance
activities built into most good enterprise-level task management software products.

Software dimensions criss-crossing nearly all lines of task management products
include task creation, task visualization, notifications, assign resources, compatibility,
configurability, scalability, and reporting


Task creation encompasses collaborative capabilities for turning ideas into actions
(tasks). Includes activities involved before setting tasks, particularly patterns of
collaboration involving planning



Task visualization encompasses presentation of tasks, most often through time
and list forms. Priority visualization encompasses classification (e.g., budget, time,
stakeholder) and mechanism (e.g., color code or text). Calendaring covers
scheduling (e.g., availability, meetings, appointments and other potential conflicts)
and notifications.



Notifications encompass configurable settings for informing past, present and
pending deadlines.

84



Assigning resources encompasses the ability to delegate tasks and tools to single
or multiple people.



Compatibility encompasses the ability of a task management environment to
connect to other systems, software and environments. It includes setting a
structure and restrictions on communication going from the task management
environment to other software, systems and environments.



Configurability encompasses ability to add, remove and manage functionality and
usability in task management environments.



Scalability encompasses ability to perform a task properly when a change in the
quantity of users is done to meet the specific task requirements.



Reporting encompasses presentation of information by displaying either in tabular
or graphical display.

85

Following state machine diagram describes different states of a task over its life cycle.
This diagram is referenced from IBM.

Fig. 18

86

4.6

Network Operating Systems

Introduction to Networks:

A network is a group of connected computers that allow people to share information
and equipment. Computers connected to a network can share equipment such as a
printer, file server or scanner. Sharing equipment allows companies to save money
since several people on the network can use the same equipment. It allows you to
easily share information with other people which is especially useful when working
together on a project and there is a need to access the same files.

There are several types of networks. A Local Area Network (LAN) is a network that
connects computers that are usually located in the same building. A LAN can connect
from as few as two computers to several hundred computers.

Fig. 19

87

A Metropolitan Area Network (MAN) is a network that connects two or more local area
networks in the same city.

A Wide Are Network (WAN) is a network that connects two or more local area
networks or metropolitan area networks across the country or world. When a single
company owns and controls a wide area network, the WAN is referred to as an
enterprise network. The Internet is the largest wide are network (discussed in the
following chapter).

Network Hardware:

A network requires special hardware to allow computers on the network to
communicate. Computers usually come with networking capabilities built into the
motherboard. Some computers are equipped with a Network Interface Card (NIC),
which is an expansion card inside a computer that offers networking capabilities.

Fig. 20

88

Cables are the wires that physically connect computers and equipment on a network.
There are two main types of cables that are used on a network: twisted pair and fiberoptic. Twisted pair cable is the most commonly used and is available in several
different categories. Each category supports a different speed, which is measured in
megabits per second (Mbps). Category 5 (CAT-5) twisted pair cables support speeds
up to 100 Mbps, Category 5e (CAT-5e) speeds of 1,000 Mbps, and Category 6 (CAT6) support speeds of up to 10,000 Mbps. Fiber-optic is an expensive type of cable but
it can carry information significantly faster (near infinite speed) and over longer
distances than twisted pair cable. It is also less susceptible to interference, more
secure and you will never have to upgrade fiber-optic cable as it can transmit
information near infinite speed.

A router is a device that determines the route, or path, along which information is
transferred on a network. A router is often used to connect a Local Area Network to
another network in order to allow every computer on a network to share one Internet
connection. A router connects to a switch or hub unless the router has a built-in switch
or hub that can connect all the computers on a network.

A switch or hub is a device that provides a central location where cables from each
computer or piece of equipment on a network come together. A switch or hub, acts like
a traffic cop, managing the flow of information on a network. When a network uses a
switch, all computers always have full speed access to the network. When it uses a
hub, all the computers must share the speed available to the network, which means a
busy network or large file transfers will slow down the speed of the entire network.

Ethernet is the most popular hardware standard used on LANs. There are several
Ethernet standards (e.g. Gigabit Ethernet or 10 Gigabit Ethernet) and each one can
exchange information on a network at a certain speed which is measured in megabits
per second (Mbps). All the hardware on an Ethernet network must support the same
Ethernet standard.

89

How Information is Stored on a Network:

A peer-to-peer network provides a simple and inexpensive way to connect computers
and is ideal for home and small office networks. Each person on a peer-to-peer
network stores their files on their own computer and each person can access shared
files stored on other computers on the network. This makes the files difficult to
manage, back up and protect but if one computer malfunctions, the rest won’t be
affected. Each computer on a peer-to-peer network must use the same operating
system, such as Windows.

A client/server network provides a highly efficient way to connect computers and is
ideal for larger companies and when sharing large amounts of information between
computers. All the files on a client/server network are stored on the server, which
makes the files easy to manage, back up and protect. However if the server
malfunctions the whole network will be affected. A client/server network can connect
computers using the same or different operating systems such as Windows XP and
Mac OS X.

Client/Server networks have a system administrator who manages the network. A
system administrator can perform tasks such as adding new computers to the network
and backing up information on the server.

90

4.7

Protecting Data on a Network

A network must be protected from unauthorized access to ensure the security of
information and equipment on the network. A firewall is special software or hardware
designed to protect a private network from unauthorized access. Companies often use
firewalls to control the information that passes between a private network and the
Internet. All the information entering or leaving the network passes through the firewall,
which examines the information and blocks information that does not meet the security
criteria.

Permissions, also known as privileges, control access to the information and
equipment on a network. Individual permission can be set up for each file, folder,
printer and other equipment on a network. Permissions can deny access or specify the
type of access each person on a network receives. You also usually have to enter a
user name and password to log in to a network. This ensures that only authorized
people can access the information stored on a network.

Wireless Networking:

A wireless network allows computers to share information using radio signals instead
of cables. Wireless networking is one of several ways to connect the computers or
multimedia devices at home or in the office. In a wireless network, all the devices in
home broadcast their information to one another using radio signals.

91

Fig. 21

This can make networking easy. It also makes it a free to move any devices connected
to the network around such as laptops, earphones and security devices. The Institute
of Electrical and Electronics Engineers wireless-Ethernet specification, known as IEEE
802.11, designated two techniques of communicating between devices for speeds up
to 2 Mbps. The first one is direct-sequence spread spectrum (DSSS) and second one
is frequency-hopping spread spectrum (FHSS). Both communication techniques,
direct-sequence spread spectrum (DSSS) and frequency-hopping spread spectrum
(FHSS), use the frequency-shift keying (FSK) technology.

Also, both are based on spread-spectrum radio waves in the 2.4-gigahertz (GHz)
range. Spread spectrum means that data is sent in small pieces over a number of the
discrete frequencies available for use at any time in the specified range. Devices using
DSSS communicate by splitting each byte of data into several parts and sending them
on different frequencies. DSSS uses a lot of the available bandwidth at about 22
megahertz (MHz). On the other hand devices using FHSS send a short part of data,
shift frequencies (hop) and then send another short part.

92

Since the FHSS devices that are communicating agree on which frequencies to hop to,
and use each frequency for a short of time (less than 400 milliseconds) before moving
on, several independent FHSS networks can exist in the same physical area without
interfering with each other. FHSS devices use 1 MHz or less of the available
bandwidth, because they use any given frequency for a short time. FHSS devices
have less probability of interference than DSSS devices but DSSS is capable of much
greater speed than FHSS since these devices can send a lot more data at the same
time. Currently, FHSS-based devices are easier to produce and cheaper.

Compare to wired networks, wireless networks are much easier for unauthorized
people to access. To help protect data transmitted on a wireless network, there are
two security standards that specify the way that data is encrypted, or scrambled, when
transmitted over a network – Wired Equivalent Privacy (WEP) and Wireless Protected
Access (WPA). WPA offers much more security than WEP.

93

EE 120
Information Technology 1

Theoretical Test

94

Information Technology 1
TEST 1

1. Name the four categories in which the Computers are divided.

2. Describe the difference between hardware and software.

3. What is the function of the CPU?

4. What is the big board located at the base of the computer (to which everything is
plugged into) called and what does it hold?

5. What is the function of a modem?

6. Name 5 Output Devices.

7. What is a database and what are database programs commonly used for?

8. Describe the meaning of Ergonomic.

95

Information Technology 1
TEST 2

1.

Name 10 examples of Database Management Systems.

2.

What is the most recognized and used hierarchical database?

3.

Name 5 well-kwon Network Databases

4.

Name the first who proposed and formulated the relational model for Database
Management

5.

What does an operating system do?

6.

Name 5 Operating Systems

7.

Describe the Task Management

8.

What is a network and what are some of the advantages of using a network?

9.

What is a client/server network?

10.

What are the two security standards that specify the way that data is encrypted
on a wireless network and which one is more secure?

96

Information Technology 1
TEST 1 – Solution

1.

Computers are divided into four categories by size, cost, and processing ability.
They are supercomputer, mainframe, minicomputer, and microcomputer, more
commonly known as a personal computer. Personal computer categories
include desktop, network, laptop, and handheld.

2.

Computer hardware is those parts of the computer that you can actually see
and touch (eg. CPU, mouse, printer, monitor, etc). Software is a set of
electronic instructions that tell a computer what to do. You cannot see or touch
the software but you can see and touch the packaging the software comes in

3.

The CPU processes instructions, performs calculations and manages the flow
of information through a computer system, i.e. it communicates with input,
output and storage devices to perform certain tasks.

4.

The really big board located at the base of the computer (to which everything is
plugged into) is called the motherboard, because it carries the microprocessor
and memory chips, as well as other internal components that enable the
system to function. A motherboard is the main circuit board of the computer. All
electrical components plug into the motherboard.

5.

A modem allows a computer to send and receive information through a
telephone line. A modem translates computer information into a form that can
transmit over telephone lines.
A modem also translates the information it receives into a form a computer can
understand. We can distinguish between two types of modems, internal and
external.

6.

Monitors, Printers, Speakers, Head phones and Web Cameras

97

7.

A database stores and manages a collection of information related to a
particular subject or purpose. A database program helps to manage large
collections of information and commonly used to manage mailing lists, phone
directions, product listings and payroll information.
Commonly used database programs include Microsoft Access, Corel Paradox
and FileMakerPro.

8.

Ergonomics is the science of fitting the job to the worker and adapting the work
environment to the needs of humans. An overall goal of ergonomics is to
promote health and safety and to optimize productivity.

98

Information Technology 1
TEST 2 – Solution

1.

Adabas, Adapter Sever Enterprise, Alpha Five, Coputhink`s View Wise, CSQL,
Daffodil DB, Data Ease, File Maker, Firebird, Glom, IBM DB2, IBM UniVerse,
Ingres, Informix, Microsoft Visual Fox Pro, MonetDB, MySQL, Open Link
Virtuoso, Open Office Org.Base, Oracle Database, Par Accel, PostgreSQL,
Progress, SQL Anywhere, SQLite, Teradata, Unisys OS 2200 databases, Kexi,
WX2, Mark Logic, Microsoft Access, Microsoft SQL Server

2.

IMS from IBM

3.

Digital Equipment Corporation DBMS-10, Digital Equipment Corporation
DBMS-20, Digital Equipment Corporation VAX DBMS, Honeywell IDS
(Integrated Data Store), IDMS (Integrated Database Management System),
Oracle CODASYL DBMS, Raima Data Manager (RDM) Embedded, RDM
Server, Turbo Image, Univac DMS-1100

4.

E.F.Codd in 1969

5.

An operating system is what controls and coordinates the use of the computer
hardware among the application programs, or software, for the user. Without
an operating system, complex computers would be a useless heap of metal.

6.

MS-DOS, Windows 3.1, Windows 95/98/Me, Windows NT, Windows 2000,
Windows XP, Unix, Linux, Mac OS X

7.

Task management is the process of managing a task (or task portfolio) through
its life cycle including planning, testing, tracking and reporting

8.

A network is a group of connected computers that allow people to share
information and equipment. Computers connected to a network can share
equipment such as a printer, file server or scanner. Sharing equipment allows

99

companies to save money since several people on the network can use the
same equipment. It also allows you to easily share information with other
people which is especially useful when working together on a project and there
is a need to access the same files and this improves efficiency.

9.

A client/server network provides a highly efficient way to connect computers
and is ideal for larger companies and when sharing large amounts of
information between computers. All the files on a client/server network are
stored on the server, which makes the files easy to manage, back up and
protect. A client/server network can connect computers using the same or
different operating systems such as Windows XP and Mac OS

10.

To help protect data transmitted on a wireless network, there are two security
standards that specify the way that data is encrypted when transmitted over a
network: 1) Wired Equivalent Privacy (WEP) and 2) Wireless Protected Access
(WPA). WPA offers much more security than WEP.

100

KEY TO EVALUATION

PER CENT

MARK

88 – 100

1

75 – 87

2

62 – 74

3

50 – 61

4

0 – 49

5

101

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