JBD Computer Studies Book 10

Chapter 4

COMPUTER
VIRUSES

Objectives

After completing this chapter, you will be able to:
y Define computer virus and describe how computer viruses spread.
y Explain the different types of computer viruses.
y List the symptoms of a computer virus infection.

C Ooncept verview

There has been a rapid and significant
development in the field of computer
technology during the seventies. In the eighties,
the Information Age dawned and the power of
electronic data processing was brought within
the reach of ordinary people. Our new founded
power to process information and the use of
machines that enhanced the quality of our lives
is under attack by viruses. A computer virus is a
special kind of computer program which:

• Spreadsacrossdisksandnetworksbymaking
copies of itself, usually surreptitiously.

• Can produce undesired side-effects in
computers in which it is active.

Some viruses are mild, and only cause messages
to appear on the screen, but others are destructive
and can wipe out the computer’s memory or
even cause more severe damage.

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Computer Virus Defined
Computer virus is one of the biggest disasters that may strike a computer system.
A computer virus is a program or piece of code that is loaded onto your computer
without your knowledge and runs against your wishes. Viruses can also replicate
themselves. All computer viruses are man-made. A simple virus that can make
a copy of itself over and over again is relatively easy to produce. Even such a
simple virus is dangerous because it will quickly use all available memory and
bring the system to a halt. An even more dangerous type of virus is one capable
of transmitting itself across networks and bypassing security systems.
Since 1987, when a virus infected ARPANET, a large network used by the Defense
Department and many universities, many antivirus programs have become
available. These programs periodically check your computer system for the best-
known types of viruses.

How Does a Virus Spread
Computer virus is a computer program designed to copy itself into other pro-
grams, with the intention of causing mischief or damage. A virus will usually
execute when it is loaded into a computer’s memory. On execution, it instructs
its host program to copy the viral code into any number of other programs and
files stored in the computer. The corrupted programs may continue to perform
their intended functions while also executing the virus’s instructions, thus fur-
ther propagating it.

Infections spread from machine to machine, and from organisation to organisa-
tion, in a number of ways.

Viruses can be transmitted by:

• Booting a PC from an infected medium

• Executing an infected program

• Opening an infected file

Common routes for virus infiltration include:

• Removable media that users can exchange

• Email attachments

• Pirated software

• Shareware

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Types of Computer Viruses
There are many kinds of viruses. Viruses come in a wide variety. The level
of destructiveness of viruses varies widely. Virus behaviour can range from
annoying to destructive. They are of the following types:

Boot Sector Viruses
Boot sector virus infects removable disk and hard drives. All disks and hard
drives contain smaller sections called sectors. The first sector is called the boot.
The boot carries the Mater Boot Record (MBR). MBR functions to read and load
the operating system. So, if a virus infects the boot or MBR of a disk, your hard
drive can become infected if you re-boot your computer while the infected disk
is in the drive. Once your hard drive is infected all diskettes that you use in your
computer will be infected. Boot sector viruses often spread to other computers by
the use of shared infected disks and pirated software applications. The best way to
disinfect your computer of the boot sector virus is by using antivirus software. The
examples of boot sector viruses are Disk Killer, Stoned and Michelangelo.

File Infecting Viruses
File infecting viruses infect executable program files having an extension .exe,
.com, or .dll. These viruses either overwrite or modify the contents of executable
files. When these infected files are executed, the virus gets activated and remains
present in the main memory even after the execution of the file is over. When
another file is executed, this virus attaches itself to the new file and thus another
file gets infected. File viruses can spread by using pen drives, Compact Disks,
over the network, or through remote access. The examples of file viruses are
Friday the 13th, Enigma, Nemesis and Cascade.

Macro Viruses
Macro virus is a computer virus that “infects” a Microsoft Word or similar
application and causes a sequence of actions to be performed automatically
when the application is started or something else triggers it. A typical effect
is the undesired insertion of some comic text at certain points when writing a
line. Macro viruses infect data files either by modifying macro procedure or by
attaching macro procedures with these data files. A macro virus can be spread
through e-mail attachment, disks, networks, modems and the Internet. The
examples of macro viruses are W97M.Melissa and WM.NiceDay.

Polymorphic Viruses
Polymorphic virus is a computer virus which is capable of mutating itself when
it replicates, making it more difficult to identify with ordinary antivirus software.

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Computer Studies-10 53

To effectively find such viruses, antivirus software needs to have more complex
algorithms available to help it identify distinctive patterns which can betray
the presence of a virus even when the code behind the virus is not known to
the software. The examples of polymorphic viruses are Involuntary, Stimulate,
Cascade, Phoenix, Evil and Proud.

Script Viruses
Script viruses infect programs written in scripting languages, such as Visual Basic
Script and JavaScript. These languages are hosted under Windows Scripting
Host (WHS), an active scripting component that is available on the Windows
98 and Windows 2000 operating systems. Script viruses spread by attaching
themselves to data files. It can spread through e-mail, floppy disks and CDs. It
can also infect computer while downloading programs from the Internet. It can
propagate through Internet Relay Chat (IRC). It can infect a computer through
various scripting environments, such as Windows Help, Windows installation
files, and Windows registry files. It is easy to write code for script viruses because
the code for these viruses can be written using a high-level language.

Stealth Viruses
Stealth virus is a computer virus that uses various mechanisms to avoid detec-
tion by antivirus software. Typically, when an antivirus program runs, a stealth
virus hides itself in memory, and uses various tricks to also hide changes it has
made to any files or boot records. The virus may maintain a copy of the original,
uninfected data and monitor system activity. When the program attempts to ac-
cess data that’s been altered, the virus redirects it to a storage area maintaining
the original, uninfected data. A good antivirus program should be able to find a
stealth virus by looking for evidence in memory as well as in areas that viruses
usually attack. The examples of stealth viruses are Frodo, Joshi and Whale.

Parasitic Viruses

Parasitic viruses attach themselves to programs, also known as executables.
When a user launches a program that has a parasitic virus, the virus is surrepti-
tiously launched first. To cloak its presence from the user, the virus then triggers
the original program to open. The parasitic virus, because the operating system
understands it to be part of the program, is given the same rights as the program
to which the virus is attached. These rights allow the virus to replicate, install
itself into memory, or release its payload. In the absence of anti-virus software,
only the payload might raise the normal user’s suspicions. A famous parasitic
virus called Jerusalem has a payload of slowing down the system and eventually
deleting every program the user launches.

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Symptoms of Virus Infection

Computer viruses are designed to attack personal and business computers,
ranging from simply affecting your computer’s performance to stealing valuable
information. It is vital to protect yourself and your computer from these threats
by using an anti-virus program, such as AVG Free, to ensure the safety of your
personal data. Some of the symptoms of virus infection are discussed below:
• The computer runs more slowly than normal.
• The computer stops responding or locks up often.
• The computer crashes and restarts every few minutes.
• The computer restarts on its own and then fails to run normally.
• Applications on the computer does not work correctly.
• Erases the files or programs from the system.
• Appearance of strange message or strange patterns on the screen.

Tips for Safe Computing

Computer virus attacks have become one of the biggest threats to an organization.
The organizations spend large amount

of money to prevent, detect and recover from computer virus attacks. The spread

of computer virus infections can be

stopped through the practice of safe computing. The following are a list of some
recommendations for safe computing:
• Install the latest updates from Microsoft Update on the computer.
• Update the antivirus software on the computer. Then, perform a thorough

scan of the computer by using the antivirus software.
• Do not load illegal software on your computer. The illegal software contains

viruses.
• Allow only genuine users to use the computer under supervision.
• Never load unknown disks into your system unless you make sure they are

virus free.
• Back up your files on a regular basis. If a virus destroys your files, at least you

can replace them with your backup copy.

AntiVirus Software

Antivirus software is a program designed to detect and remove viruses from
the computer system. It must be updated frequently for protection against new
viruses. It resides in the memory so that it detects the viruses at the time of entry
and prevents them from doing any damage to the system. Some popular anti-
virus software available are: Norton AntiVirus, McAfee VirusScan and SmartDog.

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Computer Studies-10 55

C Dompu- ictionary

Computer virus : A computer program designed to copy itself into other
programs, with the intention of causing mischief or
damage.

Boot virus : A computer virus designed to infect the boot sector of
the disk.

File virus : A computer virus designed to infect executable
program files having extensions .exe, .com, or .dll.

Macro virus : A computer virus that “infects” a Microsoft Word or
similar application and causes a sequence of actions
to be performed automatically when the application is
started or something else triggers it.

Polymorphic virus : A computer virus which is capable of mutating itself
when it replicates, making it more difficult to identify
with ordinary antivirus software.

Recap

• A computer virus is a special kind of computer program which:

Spreads across disks and networks by making copies of itself, usually
surreptitiously.

Can produce undesired side-effects in computers in which it is active.

• Boot sector virus infects diskettes and hard drives.

• File infecting viruses infect executable program files having an extension
.exe, .com, or .dll.

• Macro virus is a computer virus that “infects” a Microsoft Word or similar
application and causes a sequence of actions to be performed automatically
when the application is started or something else triggers it.

• Polymorphic virus is a computer virus which is capable of mutating itself
when it replicates, making it more difficult to identify with ordinary antivirus
software.

• Script viruses infect programs written in scripting languages, such as Visual
Basic Script and JavaScript.

• Stealth virus is a computer virus that uses various mechanisms to avoid
detection by antivirus software.

• Parasitic viruses attach themselves to programs or executable files.

• Antivirus software is a program designed to detect and remove viruses from
the computer system.

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Review Yourself

1. State whether the following statements are true or false.

a. Our new founded power to process information and the use of machines
that enhanced the quality of our lives is under attack by viruses.

b. A virus will usually execute when it is loaded into a computer’s memory.

c. Antivirus often spread to other computers by the use of shared infected
disks and pirated software applications.

d. Boot sector virus is a computer virus that uses various mechanisms to
avoid detection by antivirus software.

e. Antivirus resides in the memory so that it detects the viruses at the time
of entry and prevents them from doing any damage to the system.

2. Fill in the blanks.

a. A ____________ is a special kind of computer program which spreads across
disks and networks by making copies of itself, usually surreptitiously.

b. ______________ viruses infect executable program files having an
extension .exe, .com, or .dll.

c. _____________ virus is a computer virus which is capable of mutating
itself when it replicates, making it more difficult to identify with ordinary
antivirus software.

d. _____________ virus is a computer virus that uses various mechanisms to
avoid detection by antivirus software.

e. _____________ viruses infect programs written in scripting languages,
such as Visual Basic Script and JavaScript.

f. _____________ software is a program designed to detect and remove
viruses from the computer system.

3. Match the following.

Boot virus A program designed to detect and remove viruses from the
infected programs or files in the computer system.

Antivirus The portion of a disk reserved for the self-starting
portion of an operating system.

Stealth A computer virus designed

virus to infect the boot sector of the disk.
MBR
A computer virus designed to infect executable program
files having extensions .exe, .com, or .dll.

File virus A computer virus that uses various mechanisms to
avoid detection by antivirus software.

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4. Give the appropriate technical term for the following.
a. A computer program designed to copy itself into other programs, with
the intention of causing mischief or damage.
b. A computer virus designed to infect the boot sector of the disk.
c. A computer virus designed to infect executable program files having
extensions .exe, .com, or .dll.
d. A computer virus that “infects” a Microsoft Word or similar application
and causes a sequence of actions to be performed automatically when the
application is started or something else triggers it.
e. A computer virus which is capable of mutating itself when it replicates,
making it more difficult to identify with ordinary antivirus software.


5. Answer the following questions.

a. What is a computer virus?
b. How do computer viruses spread? Explain in brief.
c. What is a boot sector virus? Give any two examples of boot sector

viruses.
d. What is a file infecting virus? Give any two examples of file infecting

viruses.
e. What is a macro virus? Give any two examples of macro viruses.
f. What is polymorphic virus? Give any two examples of polymorphic

viruses.
g. What is script virus?
h. Explain how Stealth viruses infect the computer system?
i. What is parasitic virus? How do parasitic viruses infect the computer

system.
j. List some symptoms of a virus infection.
k. List some precautions that must be observed to avoid virus infection.
l. What are antivirus software? Give examples.

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Chapter 5

CYBER LAW
AND

COMPUTER
ETHICS

Objectives

After completing this chapter, you will be able to:
y Define cyber law and explain its importance.
y Identify and explain the different laws included in the cyber law.
y Define cyber crime and Intellectual Property Rights.
y Explain the objectives of the cyber law of Nepal.
y Explain the purpose of some of the international cyber laws.
y Define computer ethics and list the ten commandments of computer ethics.

C Ooncept verview

Success in any field of human activity leads to
crime that needs mechanisms to control it. Legal
provisions should provide assurance to users,
empowerment to law enforcement agencies
and deterrence to criminals. Crime is no longer
limited to space, time or a group of people.
Cyber crime is any illegal behaviour committed
by means of, or in relation to, a computer
system or network, including such crimes as
illegal possession [and] offering or distributing
information by means of a computer system or
network.Law encompasses the rules of conduct:

• that have been approved by the government,

• which are in force over a certain territory,
and

• which must be obeyed by all persons on
that territory

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Cyber Law Defined

Cyber law is a generic term which refers
to all the legal and regulatory aspects of
Internet and the World Wide Web. Anything
concerned with or related to or emanating
from any legal aspects or issues concerning
any activity of netizens and others, in
Cyberspace comes within the ambit of Cyber
law.

The use of technology by individuals and organizations for communication and
business has made it imperative for persons to understand the implications and
legal mechanisms adopted. Cyber law encompasses a wide variety of political
and legal issues related to the Internet and other communications technology.
Cyber law encompasses laws relating to: Digital signature law, cyber crime law,
intellectual property rights law, telecommunication law, data protection and
privacy law.

Digital Signature Law

Digital signature take the concept of traditional paper-based signing and turn
it into an electronic “fingerprint”. This “fingerprint,”’ or coded message, is
unique to both the document and the signer and binds both of them together.
The digital signature ensures the authenticity of the signer. Any changes made
to the document after it is signed invalidate the signature, thereby protecting
against signature forgery and information tampering. Digital signatures help
organizations sustain signer authenticity, accountability, data integrity and non-
repudiation of electronic documents and forms. Digital signature law provides a
legal framework to facilitate and safeguard electronic transaction in the electronic
medium. Various laws have been passed internationally to facilitate the use of
electronic records and digital signatures.

Cyber Crime Law

Cybercrime refers to any crime that involves a computer and a network, where the
computers may or may not have played an instrumental part in the commission
of a crime. Cybercrime involve illegal access to company information. Just as
with individuals, criminals can steal financial information and make purchases
using the data. The criminal may also withdraw funds from company reserves,
transferring the stolen funds through a variety of accounts and making it virtually
impossible to locate the stolen assets. In other cases, it is not money or credit
information the criminal seeks; obtaining proprietary client information and
selling it to competitors is another example of this type of high tech criminal activity.

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Intellectual Property Rights Law

Intellectual Property Rights refer to the property that is a creation of the mind
i.e, inventions, literary and artistic works, symbols, names, images and designs
used in commerce. They usually give the creator an exclusive right over the use
of his/her creation for a certain period of time. Intellectual property rights are
customarily divided into two main areas:

• Copyright, which includes literary and artistic works such as novels, poems
and plays, films, musical works, drawings, paintings, photographs, sculptures
and architectural designs. It is in a description of a thing. The copyright law
makes it illegal to produce extra copies of software for sale or use on extra
machines.

• Industrial property, which includes inventions (patents), trademarks,
industrial designs and geographic indications of source.

Laws governing Intellectual Property Rights are nation specific. They differ
from country to country according to the needs and the stage of development of
different countries. However, with gobalization it is necessary that there should
be some uniformity in the IPRs and the procedure in acquiring them. It is being
achieved by the different organizations through treaties and agreements.

Data Protection and Privacy Laws

Data protection law is essentially that
area of the law that governs what
may, and what may not, be done with
personal information. Such personal
information may be in electronic (e.g.
stored on a computer hard drive) or
manual (e.g.hand-written) form. Data
protection law allows you to check if
any organization keeps information
about you on computer and to see a
copy of this personal data. The right to
privacy may be infringed by utilizing
private data already collected for a
purpose other than that for which
it was collected and unauthorized
reading of others emails. Many nations
have enacted legislation relating to
data protection and privacy within
their jurisdictions.

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Telecommunication Law

Telecommunication has been a big growth over the last few years. More and
more people are involved in using computers and telecommunications to trans-
mit their work from their home to their offices or to other workers in the elec-
tronic chain. Telecommunication systems also fall within the territory of cyber
space and therefore would form an integral part of cyber laws.

Telecommunication law is a broad area of practice which includes legislation for
television and radio broadcasting, cable systems and transmission, wireless net-
works, radio frequencies and multimedia to name a few. The FCC regulates and
enforces this area of law.

Telecommunication law is part of the Science and Technology practice which also
includes: Biotechnology, Chemical Law, Computer and Software, Data Protec-
tion, Information Technology, Internet Law and Research and Development.

Cyber law of Nepal

Laws are established and enforced by the authority, legislation, or custom of a
given community, state or nation to maintain orderly coexistence. Basically, cy-
ber law deals with cyber-stalking, cyber-scams, online fraud, software piracy and
much more. Legal experts are working in this field to help educate and guide the
Internet community on crime prevention and the reporting of cyber crimes. After
many years of discussion and effort, recently the government of Nepal has craft-
ed the much awaited Electronic Transaction and Digital Signature Act-Ordinance
(ETDSA)-2061 (2004), popularly known as Cyber law.

Cyber law of Nepal commonly known as the Electronic Transaction and Digital
Signature Act-Ordinance was enacted in Nepal in 2061 BS (2004). The cyber law

in Nepal was formulated after making a thorough discussion of the IT Acts al-
ready implemented in other countries. It was formulated mainly to legalize the
different trading activities through the global computer network and to give a
boost to the e-goverance activities. It contains a strong provision of punishment
against cyber crimes according to the nature of the crime. The different cyber
crimes mentioned in the law include hacking, damage to computer source code,
breach of privacy and faking digital signatures. As per the provisions of law, the
government is fully authorized to punish cyber criminals - both an individual or
an institution with imprisonment and fine.

The Act provides for:

• Legal Recognition of Electronic Documents

• Legal recognition of Electronic commerce Transactions

• Admissibility of Electronic data/evidence in Court of Law

• Legal Acceptance of digital signatures

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• Punishment for Cyber obscenity and crimes
• Establishment of Cyber regulations advisory
• Committee and the Cyber Regulations Appellate Tribunal
• Facilitation of electronic filing maintenance of electronic records
The major objectives are:
• To provide legal recognition for transactions
• Other means of electronic communication, commonly referred to as “elec-

tronic commerce”, involving the use of alternatives to paper-based methods
of communication and storage of information
• To facilitate electronic filing of documents with the Government agencies
• Aims to provide for the legal framework so that legal sanctity is accorded to
all electronic records and other activities carried out by electronic means
According to the Cyber Law of Nepal, the various Cyber offences are:
• Tampering with computer source documents
• Hacking with computer system
• Publishing of information which is obscene in electronic form
• Intrusion into protected system
• Breach of confidentiality and privacy

International Cyber Law
International law governs relations between independent soverign states. It is the
body of rules, which are legally binding on States in their intercourse with each
other. The rules are not only meant for the States but also for the international
organizations and individuals. With the growing cyber crime, it has become es-
sential that laws be framed to deal with them. Some of the laws introduced in
USA are discussed below:

Fair Credit Reporting Act-1970
The Fair Credit Reporting Act of 1970 is a piece of legislation that governs the
collection, dissemination, and use of consumer credit information. Guidelines set
forth in the act serve to protect consumers from fraudulent or incorrect credit in-
formation reporting. The act is best known for enabling consumer rights when it
comes to the files that credit reporting agencies hold on them.The FCRA also lays
out guidelines for the companies that provide information to credit reporting
agencies. Those guidelines provides accurate information, investigating disputes
in a timely manner and notifications to the consumer when negative information
is about to be put on their credit report.

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Freedom of Information Act-1970
Freedom of Information Act is a law requiring that U.S. government agencies
release their records to the public on request, unless the information sought falls
into a category specifically exempted, such as national security, an individual’s
right to , or internal agency management. The act provides for court review of
agency refusals to furnish identifiable records.

Health Insurance Portability and Accountability Act (HIPAA)
The Health Insurance Portability and Accountability Act of 1996 require the
Department of Health and Human Services (HHS) to establish national standards
for electronic health care transactions and national identifiers for providers,
health plans, and employers. It also addresses the security and privacy of health
data.

Computer Ethics
Computers are capable of doing many things as per the instructions given to it.
This quality makes computers a very useful (and powerful also) tool. Because the
capabilities of computers offer such strong temptations we must be especially
careful to use them wisely. It is not the computers we should be concerned about,
but rather the people whose lives we can affect by our actions.
Computer ethics refer in general, to the behaviour and ways of thinking of
computer users in situations where a choice can affect the dignity and well being
of others.
The computer ethics institute in Washington DC, has proposed the ten
commandments of computer ethics. They are:
• Do not use a computer to harm other people.
• Do not interfere with other people’s computer work.
• Do not snoop around in other people’s computer files.
• Do not use a computer to steal.
• Do not use a computer to bear false witness.
• Do not copy or use proprietary software for which you have not paid.
• Do not use other people’s computer resources without authorization or

proper compensation.
• Do not use other people’s intellectual output.
• Always think about the social consequences of the program you are writing

or the system you are designing.
• Always use a computer in ways that demonstrate consideration and respect

for your fellow humans.

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C Dompu- ictionary

Cyber crime : Any illegal behaviour committed by means of, or in
relation to, a computer system or network, including
such crimes as illegal possession [and] offering or
distributing information by means of a computer
system or network.

Computer Ethics : The behaviour and ways of thinking of computer
users in situations where a choice can affect the dignity
and well being of others.

Cyberspace : The world-wide network of computers.

IPR : The property that is a creation of the mind i.e,
inventions, literary and artistic works, symbols,
names, images and designs used in commerce.

Data Protection Law : Area of the law that governs what may, and what may
not, be done with personal information.

Recap

• Cyber crime is any illegal behaviour committed by means of, or in relation to,
a computer system or network, including such crimes as illegal possession
[and] offering or distributing information by means of a computer system or
network.

• Digital signature take the concept of traditional paper-based signing and
turn it into an electronic “fingerprint”.

• Cyber crime refers to any crime that involves a computer and a network,
where the computers may or may not have played an instrumental part in
the commission of a crime.

• Intellectual Property Rights refer to the property that is a creation of the
mind i.e, inventions, literary and artistic works, symbols, names, images and
designs used in commerce.

• Data protection is essentially that area of the law that governs what may, and
what may not, be done with personal information.

• Telecommunication law is a broad area of practice which includes legislation
for television and radio broadcasting, cable systems and transmission,
wireless networks, radio frequencies and multimedia to name a few.

• Cyber law of Nepal commonly known as the Electronic Transaction and
Digital Signature Act-Ordinance was enacted in Nepal in 2061 BS (2004).

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Review Yourself

1. State whether the following statements are true or false.

a. Cyber crime is any illegal behaviour committed by means of, or in
relation to, a computer system or network, including such crimes as
illegal possession [and] offering or distributing information by means of
a computer system or network.

b. Intellectual Property Rights refer to the property that is a creation of the
mind i.e, inventions, literary and artistic works, symbols, names, images,
and designs used in commerce.

c. Cyber law of Nepal commonly known as the Electronic Transaction and
Digital Signature Act-Ordinance was enacted in Nepal in 2061 BS (2004).

d. Copyright Act of 1992 makes it a criminal offence to copy or steal software.

e. The Video Privacy Protection Act of 1988 imposed an entirely new body
of requirements on the federal government’s handling of information
concerning individuals.

2. Fill in the blanks.

a. _____________helporganizationssustainsignerauthenticity,accountability,
data integrity and non-repudiation of electronic documents and forms.

b. ____________ involve illegal access to company information.

c. ____________ is essentially that area of the law that governs what may,
and what may not, be done with personal information.

d. Cyber law of Nepal was enacted in Nepal in _______________.

3. Match the following.

Ethics Any illegal behaviour committed by means of, or in relation
to, a computer system or network.

Cyberspace A branch of applied ethics

which studies and analyzes social and ethical impacts of
information technology.

IPR The world-wide network of computers.

Cybercrime The property that is a creation of the mind i.e, inventions,
literary and artistic works, symbols, names, images and
designs used in commerce.

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4. Select the best answer from the list of choices.

a. _______________ refer to the property that is a creation of the mind i.e,
inventions, literary and artistic works, symbols, names, images and
designs used in commerce.

i. Data protection

ii. Intellectual Property Rights

iii. None of the above

b. Cyber law of Nepal was enacted in Nepal in __________ B.S.

i. 2061 ii. 2062 iii. 2063

c. The _____________ is a piece of legislation that governs the collection,
dissemination, and use of consumer credit information.

i. Fair Credit Reporting Act of 1970

ii. Freedom of Information Act-1970

iii. Privacy Act of 1974

5. Answer the following questions

a. What is meant by cyber law?
b. What is the function of digital signature? What is the importance of digital

signature law?
c. What are Intellectual Property Rights? What are the two main areas of

Intellectual Property Rights?
d. What is the purpose of the Copyright Act, 1992?
e. What are the main objectives of Cyber law of Nepal 2061 BS (2004)?
f. Explain the function of the following Acts:

i. Fair Credit Reporting Act of 1970
ii. Freedom of Information Act-1970
iii. The Health Insurance Portability and Accountability Act-1996
g. What is computer ethics? List ten commandments of computer ethics.

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Chapter 6

MULTIMEDIA
AND ITS

APPLICATIONS

Objectives

After completing this chapter, you will be able to:
y Define multimedia.
y Explain the advantages and disadvantages of multimedia technology.
y Explain the elements of multimedia technology.
y Define multimedia computer system and list the hardware and software require-

ments of multimedia computer system.
y Describe the application areas of multimedia.

C Ooncept verview

Multimedia industry is growing and progressing
to leaps and bounds. It is a perfect combination
of audio, still images, animation, video, text
and interactivity content forms. All these can
be recorded and played together and provides
a perfect combination of multimedia content. It
enables a user to perfectly and artistically create
videos or interactive content. A user can create
such content with the help of processing devices
like electronic or computerized devices.

Multimedia is simply multiple forms of media
integrated together. Media can be text, graphics,
audio, animation, video, data, etc. An example of
multimedia is a web page on the topic of Mozart
that has text regarding the composer along with
an audio file of some of his music and can even
include a video of his music being played in a hall.

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Multimedia Defined

Multimedia is simply multiple forms of
media integrated together. Media can be
text, graphics, audio, animation, video,
data, etc. An example of multimedia is a
web page on the topic of Mozart that has
text regarding the composer along with
an audio file of some of his music and can
even include a video of his music being
played in a hall.

The term Multimedia is said to date back to 1965 and was used to describe a
show by the Exploding Plastic Inevitable. The show included a performance that
integrated music, cinema, special lighting and human performance. Today, the
word multimedia is used quite frequently, from DVD’s to CD ROMs to even a
magazine that includes text and pictures.

Advantages of Multimedia

• Multimedia enhances text only presentations by adding interesting sounds
and compelling visuals.

• Audiences are more attentive to multimedia messages than traditional
presentations done with slides or overhead transparencies.

• People are more interested in multimedia messages which combine the
elements of text, audio, graphics and video. Communication research
has shown that the combination of communication modes offers greater
understanding and retention of information.

• Multimedia is entertaining as well as educational.

• It is quick and easier to operate for the instructor.

• It has the ability to reduce training costs and also increases learning
effectiveness in some situations.

Disadvantages of Multimedia

• One of the major disadvantages of multimedia is that it costs a lot of money

to get the equipment. Once you get this equipment, you have to make sure

that you know how to set up/use it.

• Multimedia may require a high learning curve for designers since the use of

multimedia is fairly new to most trainers and instructional designers.

• Multimedia is difficult to configure and is not always compatible.

• Modification of digital pictures leads to copyright infringement.

• Multimedia requires new protocols to handle bandwidth for sound and

videos.

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Elements of Multimedia
In today’s advanced and technology adapted society, the concept of multimedia
is ever present in many facets of life. Multimedia can be termed as the “use of
several different type of media. The types of media in a multimedia are text,
images, video, animation and audio. Multimedia can include a range of formats
from a simple PowerPoint slide show to a complex interactive simulation.

Text
Out of all of the elements, text has the most impact on the quality of the multimedia
interaction. Generally, text provides the important information. Text acts as the
keystone tying all of the other media elements together. It is well written text that
makes a multimedia communication wonderful.

Audio
Audio, or sound can be described as the “vibrations
that travel through air and can be heard by
humans”. Sound synchronized to screen display,
enables teachers to present lots of information at
once. This approach is used in a variety of ways,
all based on visual display of a complex image
paired with a spoken explanation.

Animation
Animation is the optical illusion of motion created by the consecutive display of
images of static elements. Animation adds visual impact to the multimedia project.
Animation can enhance learning by allowing greater participant enjoyment in
their learning experiences. This will ultimately result in an increased willingness to
participate in the learning, therefore contributing to greater learner participation.

Video
Video is the technology of capturing, recording,
processing, transmitting and reconstructing
moving pictures, electronic signals, or digital
media, primarily for viewing on television or
computer monitors”. It is an excellent way of
conveying the message to the user in a very limited
time. It is very useful for illustrating concepts that
involve movement.

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Images
An image can be defined as a static representation on-screen of an idea or
concept. Images include drawings, scanned photographs or charts. It plays a key
role in multimedia. It is easier to learn and retain information from images than
from text. Images help in explaining concepts through illustrations and charts.
For example, in a multimedia application a photograph of a horse along with its
textual description makes the illustration much more effective.

Multimedia Development System
Multimedia computer should support the capture, editing and viewing of video
and audio data and provide facilities for transfer of these data types between
computers either through modems or through local and wide area networks.
Multimedia computer systems require the following hardware components:
• The CPU for a multimedia computer should be Pentium 4 or other advanced

chips.
• The multimedia PC should be equipped with a monitor having Super VGA

monitors with high resolution for displaying graphics, animation and video,
• Larger storage devices (for storing large data files),
• Larger main memory (for running programs with large data size),
• Sound card and speakers to play any audio associated with a multimedia ap-

plication program.
The multimedia software can be classified as system software and authoring tools
used to develop multimedia applications. The former sets up the communications
between the system resources and the application programs.
Examples are:
• Video for Windows
• Quicktime

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Some of the recent software used in multimedia industry are:
• Photoshop
• Director
• Sound Edit
• Flash
• Picture Publisher

Areas of Multimedia
Multimedia has gained world wide acceptance in
almost all areas of human interest, whether it be-
business, presentation or simulation; education
or training; entertainment, video graphics or
animations. In the times to come, multimedia
will give a new dimension and a complete new
face to this computer industry in the world.
The following sections examine few uses of
multimedia technologies.

Multimedia in Education
The growth in use of multimedia within the education sector has accelerated
in recent years. The development of multimedia technologies for learning
offers new ways in which learning can take place in schools and the home. It
greatly enhances traditional education by providing the students with options
of individual attention at his/her own pace. It brings presentations alive with
sounds, movies, animations, and interactivity and motivates students to become
active participants in the learning process. Extending the use of multimedia
learning resources to the home represents an educational opportunity with the
potential to improve student learning. Interactive multimedia learning mode is
more like constructing a spider’s web, with one idea linked to another, allowing
choices in the learner’s path.

Multimedia in Entertainment
Multimedia games are a popular pastime and are software programs available
either as CD-ROMs or online. Some video games also use multimedia features.
Multimedia applications that allow users to actively participate instead of just sit-
ting by as passive recipients of information are called Interactive Multimedia. In
the Arts there are multimedia artists, whose minds are able to blend techniques
using different media that in some way incorporates interaction with the viewer.
Another approach entails the creation of multimedia that can be displayed in a
traditional fine arts arena, such as an art gallery.

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Multimedia in Commercial Business

Much of the electronic old and new media used by commercial artists is
multimedia. Exciting presentations are used to grab and keep attention in
advertising. Business to business, and interoffice communications are often
developed by creative service firms for advanced multimedia presentations
beyond simple slide shows to sell ideas or liven-up training. Commercial
multimedia developers may be hired to design for governmental services and
non-profit service applications as well.

Multimedia in Advertisement

As the advertising industry is often eager to embrace new technologies,
advertising is currently one of the major, mature users of multimedia technology.
Because of the nature of advertising, the industry is always looking for new and
innovative ways to approach their users. Today with the exponential growth
in web usage, the advertising industry is allocating a high level of resource to
online Internet multimedia. The development of multimedia kiosk technology
is also predicted to revolutionise the world of multimedia advertising. This will
enable the deployment of kiosks in many public locations such as shopping
centres, airports etc where users will have the ability to search for pertinent local
information.

Multimedia on the Web

Multimedia is gaining popularity on the Web with several technologies to support
use of animation, video, and audio to supplement the traditional media of text
and images. Photographs and drawings could be used to illustrate and explain
products and accessories, to demonstrate the workings of technology and nature,
or just to make pages more attractive. Multimedia was introduced using tools
such as Java and Shockwave. Now Web pages display animations, play sound,
and allow you to interact with them.

Virtual Reality

Virtual Reality is the use of computer modeling and simulation to enable a
person to interact with an artificial three-dimensional visual or other sensory
environment. A computer-generated environment simulates reality by means
of interactive devices that send and receive information and are worn as
goggles, headsets, gloves, or body suits. The illusion of being in the created
environment (telepresence) is accomplished by motion sensors that pick up the
user’s movements and adjust his or her view accordingly, usually in real time.
In scientific and engineering research, virtual environments are used to visually
explore whatever physical world phenomenon is under study.

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C Dompu- ictionary

Animation : The optical illusion of motion created by the
consecutive display of images of static elements.

Video : The technology of capturing, recording, processing,
transmitting and reconstructing moving pictures,
electronic signals, or digital media, primarily for
viewing on television or computer monitors”.

Multimedia : The combination of multiple media such as text,
images, video, animation and audio.

Virtual Reality : A system that enables one or more users to move and
react in a computer-simulated environment.

Recap

• Multimedia industry is growing and progressing to leaps and bounds. It
is a perfect combination of audio, still images, animation, video, text and
interactivity content forms.

• The types of media in a multimedia are text, images, video, animation and
audio.

• Audio, or sound can be described as the “vibrations that travel through air
and can be heard by humans”.

• Animation is the optical illusion of motion created by the consecutive display
of images of static elements.

• Video is the technology of capturing, recording, processing, transmitting and
reconstructing moving pictures, electronic signals, or digital media, primarily
for viewing on television or computer monitors”.

• An image can be defined as a static representation on-screen of an idea or
concept.

• Interactive multimedia learning mode is more like constructing a spider’s
web, with one idea linked to another, allowing choices in the learner’s path.

• Multimedia is heavily used in the entertainment industry, especially to
develop special effects in movies and animations.

• Multimedia is gaining popularity on the Web with several technologies to
support use of animation, video, and audio to supplement the traditional
media of text and images.

• Virtual Reality is the use of computer modeling and simulation to enable a
person to interact with an artificial three-dimensional visual or other sensory
environment.

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Review Yourself

1. State whether the following statements are true or false.

a. Multimedia enhances text only presentations by adding interesting
sounds and compelling visuals.

b. Video is the optical illusion of motion created by the consecutive display
of images of static elements.

c. Multimedia applications that allow users to actively participate instead
of just sitting by as passive recipients of information are called interactive
multimedia.

d. Multimedia is gaining popularity on the Web with several technologies to
support use of animation, video, and audio to supplement the traditional
media of text and images.

e. Artificial Reality is the use of computer modeling and simulation to
enable a person to interact with an artificial three-dimensional visual or
other sensory environment.

2. Fill in the blank.

a. _______________ is the combination of multiple media such as text, images,
video, animation and audio.

b. ________________ can be described as the “vibrations that travel through
air and can be heard by humans”.

c. ________________ is the optical illusion of motion created by the
consecutive display of images of static elements.

d. ________________ is the use of computer modeling and simulation to
enable a person to interact with an artificial three-dimensional visual or
other sensory environment.

3. Select the best answer from the list of choices.

a. A computer-delivered electronic system that allows the user to control,
combine, and manipulate different types of media, such as text, sound,
video, computer graphics and animation.

i. Monomedia ii. Multimedia

iii. Elecronic media iv. Hypermedia

b. The optical illusion of motion created by the consecutive display of images
of static elements.

i. Graphics ii. Video

iii. Animation iv. Text

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c. Multimedia computer systems require the following hardware components.

i. Powerful microprocessor ii. Large main memory

iii. Sound card and speakers iv. All of the above

d. The different software used in multimedia industry are:

i. Photoshop and Director ii. Microsoft Word

iii. All of the above iv. All of the above

e. A technology that allows people to enter and interact with three
dimensional computer graphics world.

i. Virtual system ii. Virtual reality

iii. Graphics system iv. None of the above

4. Match the following.

Multimedia The optical illusion of motion created by the consecutive

display of images of static elements.

Video A static representation on-screen of an idea or concept.

Virtual The combination of multiple

Reality media such as text, images, video, animation and audio.

Image A system that enables one or more users to move and react

in a computer-simulated environment.

Animation The technology of capturing, recording, processing,

transmitting and reconstructing moving pictures,

electronic signals, or digital media, primarily for viewing

on television or computer monitors”.

5. Answer the following questions.

a. What is multimedia? What are the main elements of a multimedia program?

b. State three advantages of multimedia technology.

c. State three disadvantages of multimedia technology.

d. What is computer animation?

e. What is a multimedia computer system? What are the components of
multimedia setup?

f. Name some common multimedia software packages.

g. What is the role of multimedia in education?

h. What is the role of multimedia on Web?

i. How is multimedia useful in advertising?

j. Explain the role of multimedia in business.

k. What is Virtual Reality?

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Chapter 7

COMPUTER
NUMBER
SYSTEM

Objectives

After completing this chapter, you will be able to:
y Define computer number system and explain the different types of computer

number system.
y Explain how to convert from one base system to another base system.
y Explain how to perform arithmetic operations on binary number system.
y Define the important terms related to storage system.

C Ooncept verview

Computer can serve as a tool to improve efficiency of any operation to be
performed. It is an electronic device. Data in a computer can be represented
by the presence or absence of electronic signals. In most computers, data is
represented as a group of binary digits: a combination of 0’s and 1’s. This is
known as representation of data. The number system used to represent data in a
computer is therefore known as binary number system.
Number system is an organized and systematic way of representing numbers.
The number system most familiar to us is decimal number system. This uses ten
digits (0,1,2,3,4,5,6,7,8,9) to represent numbers. However, other number systems
also exist-binary, octal and hexadecimal. These systems are used in operating
electronic devices.

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Decimal Number System
A system of numbers having base 10 is called decimal number system. It utilizes
the symbols of the numbers from 0 to 9. It is also called denary number system.
The value of decimal number is determined by
• the digit
• the position of the digit in the number
• the base or radix of the number system
For example, 758 is a decimal number.
758 = 7 x 102 + 5 x 101 + 8 x 100

= 7 x 100 + 5 x 10 + 8 x 1
= 700 + 50 + 8
= 758

Binary Number System
A system of numbers consisting of only two digits, 0 and 1 is called binary number
system. This is ideal for representing patterns of bits, with 0 expressing a bit that
is turned off and 1 expressing a bit that is turned on. It has base 2. The 0s and 1s
can be arranged in various combinations to represent all the numbers, letters and
symbols that can be entered into the computer.

Octal Number System
A system of numbers having base 8 is called octal number system. Octal number
system utilizes the digits from 0 to 7. The positional weights are based on
the powers of 8. The octal system is used in computing as a simple means of
expressing binary quantities.

Hexadecimal Number System
A system of numbers having base 16 is called hexadecimal number system. The
symbols used in this system are the decimal digits 0 through 9 and six additional
digits which are generally represented as A, B, C, D, E and F. The letters are used
because our standard numbering system has only 10 distinct digits in decimal
number system. The positional weights are based on the powers of 16.

Binary to Decimal Conversion
A binary number can be converted to its decimal equivalent by the following
method.
• Multiply each digit of binary number by base of the number (i.e. 2) raised to

the power of the positional notation taken from the extreme right.
• All the products of multiplication are added to get the decimal equivalent of

the number.

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Solved Examples

Convert the binary number (101010)2 to it decimal equivalent.
Solution:

Binary digits = 1 0 1 0 1 0

= 5 4 3 2 1 0
= (1x25)+( 0x24) + (1x23) + (0x22)+(1x21)+(0x20)

= (1x32) + (0x16) + (1x8) + (0x4) + (1x2) + (0x1)

= 32 + 0 + 8 + 0 + 2 + 0

= 4210
Thus, (101010)2 = (42)10
Decimal to Binary Conversion
A decimal number can be converted to its binary equivalent by the following
method.

• Divide the decimal number by 2 successively.

• Keep a note of the remainders in one column.

• Repeat the process until the quotient is zero.

• The answer is obtained by writing the answer in the reverse order.

Solved Examples

Convert the decimal number 2110 into binary equivalent.
Solution:

Remainders

2 21 1

2 10 0

2 5 1

2 2 0

2 1 1

0

Thus, (21)10 = (10101)2

Decimal to Octal Conversion
A decimal number can be converted to an octal by the following method:
• The number is divided by 8.
• The dividend is written under the number. This becomes the new number.

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• The remainder is noted at the right in a column.
• Steps first to third are repeated until a zero results.
• The octal number is read from the column of remainders from the bottom-up.

Solved Examples

Convert 411910 into octal.
Solution:
Remainders
8 4119 7
8 514 2
8 64 0
8 8 0
8 1 1
0
Thus, 411910 = 100278

Octal to Decimal Conversion
An octal number can be converted to its decimal equivalent by the following
method.
• The octal digits are written as powers of 8.
• Each power of 8 is converted into its decimal equivalent term.
• These terms are added to produce the required decimal number.

Solved Examples

Convert 6258 into decimal equivalent.
Solution:

Octal digits = 6 2 5

= 2 1 0

= (6x82)+(2x81)+(5x80)

= (6x64) + (2x8) + (5x1)

= 384 + 16 + 5

Thus, 6258 = 40510

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Octal to Binary Conversion
This is a straight forward method which instructs just to substitute the respective
values from the following table.
Octal Binary
0 000
1 001
2 010
3 011
4 100
5 101
6 110
7 111

Solved Examples

Convert 1058 to its binary equivalent.
Solution:
Octal digit = 1 0 5
From the table,
1 = 001
0 = 000
5 = 101
Thus, 1058 = 0010001012
Verification:
Octal digit = 1 0 5
= (1x82)+(0x81)+(5x80)
= 6910

Change 6910 into binary equivalent.
Remainders
2 69 1
2 34 0
2 17 1
2 8 0
2 4 0
2 2 0
2 1 1
0

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Now, put the binary digits in sets of three from the extreme right.
Binary number = 1 000 101
= (001) (000) (101)
Thus, 1058 = 0010001012

Binary to Octal Conversion

Binary to octal conversion is the reverse (inverse) process of octal to binary
conversion. The method is simple. Arrange the binary number into groups of
3 bits starting at the binary point and read each set of three binary digits using
table.

Solved Examples

Convert 11010102 into octal equivalent.
Solution:

Binary digits = 1101010

Paired binary no. = (001) (101) (010)

Now, locate the corresponding octal value of 001, 101 and 010 from the
table.

Octal value = (001) (101) (010)

Obtained = 1 5 2

Thus, (1101010)2 = (152)8

Verification:

Binary number = 1 1 0 1 0 1 0

= 6 5 4 3 2 1 0
= (1x26)+(1x25)+(0x24)+ (1x23) + (0x22) + (1x21) + (0x20)

= (1x64)+(1x32)+(0x16)+(1x8)+ (0x4)+(1x2)+(0x1)

= 64+32+0+8+0+2+0

= (106)10
Now, divide 10610 by base 8 to get the required result.
Remainder

8 106 2

8 13 5

8 1 1

0

Thus, 11010102 = 1528

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Decimal to Hexadecimal Conversion

A decimal number can be converted to the equivalent hexadecimal by the
following method:

• The decimal number is divided by 16.

• The dividend is written under the number. This becomes the new number.

• The remainder is noted at the right in a column. If the number is greater than
or equal to 10 then write its symbol.

• Step first to third are repeated till a ‘0’ is produced as the new number.

• The hexadecimal number is read from the column of remainders from the
bottom-up.
Solved Examples

Convert 8210 into hexadecimal equivalent.
Solution:
Remainders
16 82 2
16 5 5
0
Thus, 8210 = 5216

Hexadecimal to Decimal Conversion

A hexadecimal number can be converted to its decimal equivalent by the following
method.

• The hexadecimal digits of the given number are written as powers of 16.

• Each power of 8 is converted into its decimal equivalent term.

• These terms are added to produce the required decimal number.

Solved Examples

Convert B3E16 into decimal equivalent.
Solution:

Hexadecimal digits = B 3 E

= 2 1 0

= (Bx162) + (3x161) + (Ex160)

= (11x162) + (3x161) + (14x160)

= (11x256) + (3x16) + (14x1)

= 2816 + 48 + 14

= 287810
Thus, B3E16 = 287810

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Computer Studies-10

Binary to Hexadecimal Conversion

A binary number can be converted into hexadecimal number by the following
method:

• The given binary number is divided into groups of four bits each.

• Each group is replaced by its hexadecimal equivalent.

Solved Examples

Convert 1110112 into hexadecimal number system.
Solution:

Binary digits = 111011

Group the given binary number in sets of four. Make the sets equal by
adding two zeros to the extreme left. Replace each group by its hexadecimal
equivalent.

0011 1011

3 B

Thus, 1110112 = 3B10
Verification:

Binary number = 1 1 1 0 1 1

Positional notation = 5 4 3 2 1 0

Procedure = (1x22)+(1x22)+(1x22)+(0x22)+(1x22)+(1x22)

= (1x32)+(1x16)+(1x8)+(0x4)+ (1x2) + (1x1)

= 32 + 16 + 8 + 0 + 2 + 1

Answer = 5910

Now, divide 5910 by base 16 to get the required result.

Remainders

16 59 11=B

16 3 3

0

Answer = 3B

Thus, 1110112 = 3B16

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Hexadecimal to Binary Conversion
The hexadecimal number system is used as a shorthand method for representing
binary numbers in the same way as the octal number system. Each hexadecimal
digit is converted to its 4-bit binary equivalent.

Solved Examples

Convert 4A816 to its equivalent binary number.
Solution:
Hexadecimal number
4 A 8
0100 1010 1000

Thus, 4A810 = 0100101010002
Verification:

Hexadecimal number = 4 A 8

Positional notation = 2 1 0

Procedure = (4x162) + (10x161) + (8x160)

= (4x256) + (10x16) + (8x1)

= 1024 + 160 + 8

= 119210
Change 119210 into binary equivalent
Remainders

2 1192 0

2 596 0

2 298 0

2 149 1

2 74 0

2 37 1

2 18 0

2 9 1

2 4 0

2 2 0

2 1 1

0

Thus, 4A816 = 0100101010002

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Binary Arithmetic
Arithmetic operations (i.e. addition, subtraction, multiplication and division) in
binary number system are simple.
The binary addition rules are shown in the table below:

Solved Examples
Add 101110 with 100101.
Solution:
1 0 1 1 1 0 (Addend)
1 0 0 1 0 1 (Augend)
1 0 1 0 0 1 1 (Sum)
The binary subtraction rules are shown in the table below:

Solved Examples
Subtract 10110 from 11011.
Solution:
1 1 0 1 1 (Minuend)
1 0 1 1 0 (Subtrahend)
0 0 1 0 1 (Difference)

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The binary multiplication rules are shown in the table below:

Solved Examples

Multiply 1011 with 10001.
Solution:
1 0 1 1
x 1 0 0 0 1
1 0 1 1
0 0 0 0 x
0 0 0 0 x x
0 0 0 0 x x x
1 0 1 1 x x x x
1 0 1 1 1 0 1 1

The binary division rules are shown in the table below:

Solved Examples

Divide 11001 by 101.

Solution:

Starting from the most significant bit of dividend.

Step 1

Divisor Dividend Quotient

101 110011 1

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101 (Subtract)

1

Step 2

Divisor Dividend Quotient

101 110011 10

101

10

Step 3

Divisor Dividend Quotient

101 110011 101

101

101

101 (Subtract)

0
BITS, Nibble, Byte and Word

A single binary digit is called a bit. As a single bit carries so little information, we
usually group them together into chunks of eight bits called bytes. Half a byte
(four bits) is called a nibble.

Modern computers have registers and a data bus which are eight bits (or a
muliple) wide (for example 16, 32 or 64 bits). We refer to this as the word size of
a particular computer, and to this unit of information as a word.

Byte

Byte is a combination of 8 bits. A byte can represent a single character, such as
a letter, a digit, or a punctuation mark. Because a byte represents only a small
amount of information, amounts of computer memory and storage are usually
given in kilobytes, megabytes, gigabytes, terabytes and petabytes, exabytes,
zettabytes and yottabytes.

Kilobyte : A unit of computer memory or data storage capacity equal to
1,024 bytes.

Megabyte : A unit of computer memory or data storage capacity equal to
1,024 KB.

Gigabyte : A unit of computer memory or data storage capacity equal to
1,024 MB.

Terabyte : A unit of computer memory or data storage capacity equal to
1,024 GB.

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C Dompu- ictionary

Binary number system : A system of numbers consisting of only two digits, 0
and 1.

Nibble : A group of 4 bits.

Byte : A combination of 8 bits.

Kilobyte : A unit of computer memory or data storage capacity
equal to 1,024 bytes.

Megabyte : A unit of computer memory or data storage capacity
equal to 1,024 KB.

Gigabyte : A unit of computer memory or data storage capacity
equal to 1,024 MB.

Terabyte : A unit of computer memory or data storage capacity
equal to 1,024 GB.
Recap

• Computer can serve as a tool to improve efficiency of any operation to be
performed.

• The number system used to represent data in a computer is therefore known
as binary number system.

• A system of numbers consisting of only two digits, 0 and 1 is called binary
number system.

• A system of numbers having base 10 is called decimal number system.

• A system of numbers having base 8 is called octal number system.

• A system of numbers having base 16 is called hexadecimal number system.

• BIT is the smallest unit of information handled by a computer.

• Nibble is a group of 4 bits.

• Byte is a combination of 8 bits.

• Kilobyte (KB) is a unit of computer memory or data storage capacity equal to
1,024 bytes.

• Megabyte (MB) is a unit of computer memory or data storage capacity equal
to 1,024 KB.

• Gigabyte (GB) is a unit of computer memory or data storage capacity equal to
1,024 MB.

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Review Yourself

1. State whether the following statements are true or false.

a. A system of numbers consisting of only two digits, 0 and 1 is called
binary number system.

b. Byte is the smallest unit of information handled by a computer.
c. Kilobyte (KB) is a unit of computer memory or data storage capacity

equal to 1,024 bytes.
d. Exabyte is a unit of information or computer storage equal to 1,024 MB.
e. Zettabyte is a unit of information or computer storage equal to 1,024 EB.

2. Answer these questions.

a. What is a number system? What are the types of number systems used
in a computer?

b. What is a binary number system? What is the base of decimal number system?

c. What is meant by byte in computer terminology? How many bytes are
there in 1011 1001 0110 1110 numbers?

d. A computer has 4KB words of main store. Each word comprises 24 bits.
How many bits are there in the whole memory?

3. Convert the following as indicated.

a. 110012 = (?)10 b. 11112 = (?)10
c 36210 = (?)2 d. 76410 = (?)2
e. 5710 = (?)8 f. 26010 = (?)8
g. 4378 = (?)10 h. 3218 = (?)10
i. 1012 = (?)8 j. 11102 = (?)8
k. 7268 = (?)2 l. 6158 = (?)2
m. 10710 = (?)16 n. 22010 = (?)16
o. 27D16 = (?)10 p. AB216 = (?)10
q. 110112 = (?)16 r. 101012 = (?)16
s. D8F916 = (?)2 t. 1AE16 = (?)2

4. Solve the following binary arithmetic. b. 101100 + 11101
a. 11011 + 10010 d. 111011 - 11011
c. 11111 - 1101 f. 110111 x 1001
e. 10111 x 11001 h. 111011 ÷ 111
g. 101111 ÷ 101

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Chapter 8

DATABASE
MANAGEMENT

SYSTEM

Objectives

After completing this chapter, you will be able to:
y Define Database Management System and list the advantages and disadvantages

of DBMS.
y Define MS-ACCESS and describe the four basic objects of MS-ACCESS.
y Explain how to create table, query, form and report in MS-ACCESS.
y Explain how to locate specific records in MS-ACCESS.
y Define relationship and explain the different types of relationships.

C Ooncept verview

A database is a collection of information that is 91
organized so that it can easily be accessed, managed and
updated. The relational model is the most popular type
of database and an extremely powerful tool, not only
to store information, but to access it as well. Relational
databases are organized as tables. The beauty of a
table is that the information can be accessed or added
without reorganizing the tables. A table can have
many records and each record can have many fields.
Tables are sometimes called a relation. For instance, a
company can have a database called customer orders,
within this database will be several different tables or
relations all relating to customer orders. Tables can
include customer information (name, address, contact,
customer number, etc.) and other tables (relations) such
as orders that the customer previously bought (this
can include item number, item description, payment
amount, payment method, etc).

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Database Management System

A database management system (DBMS), sometimes
just called a database manager, is a program that lets
one or more computer users create and access data in
a database. The DBMS manages user requests (and
requests from other programs) so that users and other
programs are free from having to understand where
the data is physically located on storage media and, in
a multi-user system, who else may also be accessing the
data. In handling user requests, the DBMS ensures the
integrity of the data (that is, making sure it continues to
be accessible and is consistently organized as intended)
and security (making sure only those with access
privileges can access the data).

On PCs, Microsoft Access is a popular example of a single-or small-group user
DBMS. Microsoft’s SQL Server is an example of a DBMS that serves database
requests from multiple (client) users. Other popular DBMSs are IBM’s DB2,
Oracle’s line of database management products and Sybase’s products.

The database management system (DBMS) is useful in the following ways:

• It reduces the data redundancy. Data redundancy means duplication of data.

• It provides facility of sharing data among different users.

• It provides data security and privacy by allowing access of data to authorized
users only.

• Adding and removing of information is quick and simple.

• DBMS maintains the integrity of data by keeping certain integrity checks on
data, ensuring that data follows specific standards.

The database management system (DBMS) has the following limitations:

• Hardware (more RAM, faster CPU) and software (DBMS) are expensive.

• Conversion from conventional file system to database approach is a costly
and time consuming operation.

• Operating costs are higher.

• Database processing tend to be more complex and highly qualified systems
and programming personnel are required.

• Backup and recovery are more difficult in a database environment.

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Relational Database Management System

Relational Database Management System (RDBMS) have become popular,
perhaps largely due to their simple data model, which is:
• Data is presented as a collection of relations
• Each relation is depicted as a table
• Columns are attributes
• Row (”tuples”) represent entities
Every table has a set of attributes that taken together as a “key” uniquely

identifies each entity
The relational database was invented by E. F. Codd at IBM in 1970. In addition to
being relatively easy to create and access, a relational database has the important
advantage of being easy to extend. After the original database creation, a new
data category can be added without requiring that all existing applications be
modified.

Microsoft Access

Microsoft Access is a relational database management system from Microsoft. It is
used to store large amounts of data. The data can be viewed, sorted, manipulated,
retrieved and printed in various ways. Access has features (such as queries and
reports) that make the DBMS more attractive and useful. To help beginners, Access
has built-in help for some of the more complex tasks, such as creating reports and
defining controls on an input form. This in-built interactive help is called Wizard.
Wizards save lots of time and effort. Microsoft Access provides a graphical user
interface that makes it very easy to define and manipulate databases.

To start Microsoft Access from the Start
button, carry out the following steps:

• Click on the Start but ton, located in
the lower-left corner of the screen.
The Start menu will appear.

• Click on All Programs. The
Programs menu will appear.

• Click on Microsoft Office.

• Click on Microsoft Office Access
2010.

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Backstage View
One of the most compelling changes in Microsoft Office 2010 is the addition
of Backstage View. It is an MS Office-wide interface and marks one of the best
improvements in the new version. Backstage View features all of the information
you need to know about your document. It has the basic stuff, like saving, opening
and closing options. You can also access recent documents from the pane and
open up brand new documents. Printing options are also packed into Backstage
View, as are file permissions and versions of the file you may be working on.
Backstage View also helpfully aligns your file properties on the right-side pane,
showcasing the length of time you’ve spent working on the open file and the
modification dates. You can even add another author to create different access
points for the file.

Create a blank database
• On the Getting Started with Microsoft Office Access page, under New Blank

Database, click Blank Database.

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• In the Blank Database pane, type a file name in the File Name box. If you
do not supply a file name extension, Access adds it for you. To change the
location of the file from the default, click Browse for a location to put your
database Button image (next to the File Name box), browse to the new
location, and then click OK.

• Click Create.
Access creates the database with an empty table named Table1, and then

opens Table1 in Datasheet view. The cursor is placed in the first empty cell in
the Add New Field column.
• Begin typing to add data, or you can paste data from another source.

The Access 2010 Environment
The initial Access screen, after creating a new database is shown below. Across
the top of the screen is the Access Ribbon, which was new in Access 2007 and
replaces the toolbars and menus seen in previous versions of Access. The Ribbon
is divided into several groups.

The Navigation Pane
The Navigation pane, at the left of the screen, is your primary navigation aid
when working with Access. By default, the list is filled with the names of tables
in the current database, but it can also display other types of objects if you click
on the drop-down list in the Navigation pane’s title bar to reveal the navigation
options.

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Here are the navigation options.
Custom

The Custom option creates a new tab in the Navigation pane. This new tab is
titled Custom Group 1 by default and contains objects that you drag-and-drop
into the tab’s area. Items added to a custom group still appear in their respective
“object type” view.

Object Type

The Object Type setting is most similar to previous versions of Access. When
selected, Object Type transforms the selection list to display the usual Access
object types:

Object Description

Table A table is a collection of related data stored in an organized manner.

Queries A query is used to filter data from the table based on some conditions.

Forms A form is a user-friendly way of entering, displaying and editing
data stored in a table.

Reports Reports are used to present the data stored in tables or queries in a
printed form.

Pages Pages allow you to create a web page which is connected to an
access database.

Macros Macros allow you to automate common tasks. A macro is a sequence
of instructions that can be carried out with a single click of the
mouse button.

Modules Modules are used to write programs to create applications.

The Ribbon

The Ribbon contains multiple tabs, each with several groups of commands. Some
tabs, like Form Layout Tools or Table Tools, may appear only when you are
working with certain objects like forms or tables. These tabs are called contextual
tabs, and they are highlighted in a contrasting color to distinguish them from
normal tabs.

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The Quick Access Toolbar
The Quick Access Toolbar is located above the Ribbon, and it lets you access
common commands no matter which tab you are on. By default, it shows the
Save, Undo, and Repeat commands. If you’d like, you can customize it by adding
additional commands.

Designing Tables
A table is a collection of data about a specific topic, such as products or suppliers.
Using a separate table for each topic means that you store that data only once,
which makes your database more efficient and reduces data-entry error. Tables
organize data into columns (called fields) and rows (called records). A common
field relates two tables so that Microsoft Access can bring together the data from
the two tables for viewing, editing, or printing.

Deciding Table Contents and Properties
Before you create your tables, you need to design it property, you must decide
about number of fields required, fields names, their fields types, their sizes and,
other properties and the PRIMARY KEY. Let us first discuss about these issues.

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Field Name

Field name is the label that tells what type of information is being stored in this
fields e.g., field name Age gives you an idea that this field stored the ages of some
persons, Similarly, field name Marks gives you and idea that this field stores
marks scored by some students.

Field Types or Data Types

Fields within a table can hold various types of data. The field type dictates what
sort of data can be stored within the field.

Access supports 10 basic data types as shown in the table below:

Data Type Storage size

Text 0-255 characters

Memo 0-65,535 characters

Number 1, 2, 4, or 8 bytes

Date/Time 8 bytes

Currency 8 bytes

AutoNumber 4 bytes

Yes/No 1 bit (0 or 1)

OLE Object Up to 1 GB

Hyperlink Upto 2048 characters

Lookup Wizard 4 bytes

The details of the data types are as follows:

Text
Text is the default field type. Text fields can contain up to 255 characters.

Memo

Memo fields can store up to 65,535 characters. They are used for storing large
information about fields e.g., in library database, a memo field can store detailed
information about books such as its edition, author and author’s background.
The memo fields cannot be indexed i.e., records cannot be arranged in the order
of memo fields.

Number

Number stores numeric data to be used for mathematical calculations. This data
type supports Bytes, Integer and Long integer to store numbers without decimals,
and the types-Single, Double and Decimal.

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Date/Time
This field type stores date and time values. Various formats can be defined for
date and time.

Currency
This type of field is used for currency values and numerical data used in
calculations. Currency values automatically include a dollar sign ($), correct
decimal and comma positions. They have an accuracy of up to 15 digits to the left
of the decimal point and up to 4 digits to the right of the decimal point.

AutoNumber
AutoNumber stores an integer that is incremented or decremented automatically
as you add or delete records. If the table does not have a primary key, then Auto
number uniquely identifies the records.

Yes/No
Yes/No is a logical type of data that can have only one of the two values, i.e., True
or False. You can adjust the format setting display as Yes/No, True/False, or On/
Off.

OLE Object
OLE Object fields can be used to store objects such as a Microsoft Excel
spreadsheet or a Microsoft Draw graphic that is created by an object application.
The maximum size is about 1 gigabyte. OLE Object fields can’t be indexed.

Lookup Wizard
A Lookup Wizard field creates a field that allows to choose a value from another
table or from a list of values using combo box. Choosing this option in the Data
Type list starts the lookup Wizard to define the data type.

Hyperlink
Hyperlink is used for storing hyperlinks. A hyperlink will link to an Internet or
Intranet site, or another location in a database or a web page.

Field Properties
The Field Property is used to select any pertinent properties for the field from the
bottom pane. Each field in a table has its own set of properties that further define
the field and how it’s used in the database. Some of the more commonly used
properties and their functions are described below:

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Field Size

The Field Size property is used to set the maximum size for data stored in a field
for Text, Number, or AutoNumber data type.

For the Text data type, you can enter a number from 0 to 255. The default setting
is 50.

For the Number data type, the Field Size property settings and their values are
related in the following way:

Setting Description

Byte Store numbers from 0 to 255

Integer Store numbers from -32,768 to 32,767

Long Integer Store numbers from- 2,147, 483, 648 to 2,147, 483, 647

Single Store numbers from 1.401298E-45 to 3.402823E38 for positive
values.

Double Store numbers between -1.797 x 10308 to +1.797 x 10308.

Format

The Format property is used to specify the data display format for a field in
a table. It can be used to customize the way numbers, date, time and text are
displayed and printed. The Format property uses different settings for different
data types. Let us look at different Format settings for different data types:

Date/Time Data Type

Date/Time data type allows to format the Date/Time field to some predefined
date and time formats. The following table shows the predefined Format property
settings for the Date/Time data type.

Setting Description

General Date It is the default setting. If the value is a date only, no time is
displayed; if the value is a time only, no date is displayed.

Long Date Displays name with day and month names.

Medium Date 6-Apr-09

Short Date 4/6/09

Long Time 5:34:23 PM

Medium Time 5:45 PM

Short Time 21:34

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