computer Unit 8

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Unit 8: Applications
Introduction
This unit consisting of five lessons covering numerous application of
computers and impact of computerization on society. Some basic
considerations concerning applications of computers are presented in the
Lesson. Computers are employed to solve problems of different nature,
Routine applications of computers in offices, use of computers in
managing commercial organizations, and application of computers in
science, engineering and research are discussed in Lesson 2.
The role of computers in modern society is a complex issue. Lesson 3
presents the scope and influence of computerization in modern society. It
identifies controversial issues and challenges for the future. Lesson 4
presents the tasks for the routine maintenance of microcomputers.
Selection of computers requires selection of different components of
computers and Lesson 5 presents the criteria for selection a
microcomputer.
Lesson 1: Basic Considerations
1.1 Learning Objectives
On completion of this lesson you will be able to
• know the criteria for justification of computer systems
• learn the information systems and their classification
• know the steps for analysis and design of computer based
systems
• know the reasons for the failure of computer systems.
Criteria for using Computers
The following are the criteria which may be used to justify the use of
computers:
Volume of data : The computer is suited to handling large volume of
data.
Accuracy : High degree of accuracy is ensured by computers and their
consistency is reliable.
Criteria for using computers

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Repetitiveness : Processing cycles that repeat time and time again are
ideally suited to computers. Once a computer is programmed it goes on
automatically performing the task as many times as required.
Complexity : Computers perform complex calculations. A computer
provides the required answers after running the program for complex
calculations.
Speed : Computers work at very high speeds. This enables them to
respond quickly to a given situation.
Common data : One item of data can be used for different computer
procedures.
Usually a combination of two or more of the above criteria justifies the
use of computers. These criteria are used to carry out the preliminary
survey to judge the suitability of applications for computerization.
Technological innovations in the recent past have increased the range of
technically feasible applications and they have also provide cost-
effective solutions to a range of problems.
If the general criteria justify that a particular application may be suitable
for computerization, then the following questions should be satisfactory
answered before any decision to computerize is taken.
• Is the use of a computer technically feasible?
• Would it be cost effective?
• Would it be socially acceptable?
Information
An information system comprises of a set of people, procedures and
equipment. It is used for the management and better control of an
organization. The function of an information system is to collect store,
process and present date to manage the business of the organization.
Processing of data is an integral part of an information system. Such
systems may be classified as :
• Deterministic
• Probabilistic, and
• Adaptive
Deterministic or mechanistic : The output from this system uniquely
determined, (example: evaluating formula).
Important questions for
computerization
Types of Information Systems.

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Probabilistic or stochastic : A degree of uncertainty exists so that the
output is specified in terms of averages or distributions (example:
random number simulations).
Adaptive or cybernetic : A system adapts itself to changes in
environment (example: a stock control problem where the re-order
strategy depends on changes in demand).
In real life few systems are truly deterministic. However deterministic
models are often created for systems which are stochastic or even
adaptive. Modeling is used for designing a computer system to represent
a real system; the computer system may be studied for analysis, control
and processing of various activities of the real system.
System Analysis
System analysis involves analysis and design of computer
implementation of a problem. The speed, power and independent
operation of a computer demands a clear analysis and complete
specification than that associated with manual systems.
A system analyst in a computer department is responsible for liaison
with users. A system analyst designs a set of procedures to fit
requirements of the users and this design includes specifications of the
programs to be developed. These specifications are implemented by
programmers. A system analyst is to perform the following tasks :
• Identification
• Feasibility study
• Investigation
• Analysis
• Design
• Implementation
• Review
• Maintenance.
Identification is deciding on an application which may require further
study for computerization.
Feasibility study is the preliminary investigation into the system to
evaluate the possibility of a computer system and estimation of costs and
benefits. It should also suggest most effective method of solution.
Investigation is the fact-finding exercise. Through investigation the
system analyst determines the requirements of the system and studies
methods and procedures for the system.
System
System Analysis
System Analysis Tasks

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Analysis is the review of the results of the investigation. This brings
together the finding of the investigation in the form of a document.
Design is the creation of the specifications for the computer programs
and manual procedures to be carried out with the computer system. This
involves the design of flowcharts or pseudocodes.
Implementation may be divided into two parts: firstly supervising the
programmers in coding and testing of the programs and secondly the
supervision of the introduction of the system. The second part concerns
instructing the users for their responsibilities.
Review is the evaluation of the system after it has been implemented.
This is to ensure that it is being applied in the manner specified by the
analyst and that it meets the intended objectives.
Maintenance is required if it is found that the system has flaws, fails to
meet requirements or the requirements change for some reasons.
Reasons for the Failure of Computer Systems
It is important to study the major causes of the failure of a computer
system. Despite all the techniques and practices, many systems are
considered failures. Some of the reasons for this could be :
• Inadequate feasibility study causing a poor design.
• Inefficient costing of the hardware, media, staffing or
development.
• Lack of acceptance by the users.
• Poor quality of documentation.
• Inflexibility to match existing procedures and practices.
• Unrealistic estimates of the time scale for design and
implementation.
Reasons for the Failure of
Computer Systems

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1.2 Exercise
1. Questions for short answers
a. Explain the term “Information technology”.
b. List the criterion of using computer for solving problem.
c. List the stages of the system life cycle.
d. What are the tasks that must a systems analyst perform?
2. Analytical questions
a. What is an information system? List the different types of
information systems and give their characteristics.
b. List and explain the stages of system analysis.
c. What is the feasibility study? Explain its purpose.
d. Explain the responsibilities of a system analyst in a computer
department.
e. Discuss briefly the main reasons for failure of computer systems.

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Lesson 2: Application Areas
2.2 Learning Objective
• know the areas where computers are employed
• identify the routine applications of computers
• know the use of computers in management
• identify scientific, industrial, medical applications of computers
• understand the importance of packages for common
applications.
2.2 Main Areas of Applications
The aim of this lesson is to focus attention on the major areas where
computers can be employed. Computer applications can be divided into
following broad are :
• Office automation
• Management applications
• Scientific, engineering and research applications.
Office automation : These applications include the use of computers for
clerical activities in public and private organizations. Office automation
involves the use of computers, in conjunction with other electronic
equipment, to automate the basic secretarial and clerical tasks of the
office. The routine nature of office work makes office procedures
suitable for automation. Reduced equipment costs now makes it cost
effective. Word processing is the basic job in on office.
Some office automation systems go far beyond the function of word
processing on networks. PCs or workstations are connected to a network
which provides access to a wide variety functions including.
• Word processing
• Spreadsheet analysis
• Drawing diagrams
• Database applications
• Electronic mail facilities
• Access to other network etc.
There may be a number of file servers and print servers connected to a
network. Popular example is a client-server arrangement. In most client-
server arrangements an application program (the client) runs on a PC or
Areas of application
Office automation
Applications through computer
networks

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workstation and communicates through the network with the server
program which runs on another computer. The server machines are
usually more powerful and are popularly dedicated to provide access to :
• A printer
• Electronic mail
• Database
• Other systems etc.
Management Applications
A commercial organization often needs information on which to base
decisions concerning the current operations and future plans. This
information should timely and accurate. Examples of the use of
computers for management and control are given below.
Stock control : A computer can process data quickly and thereby make
available information on stock levels. A computer can be used to link
widely separated warehouses, thus treating them as one vast stock
control system. Customer orders can be served from an alternative
warehouse if an item is not available in the local one. Thus the computer
enables stock holdings to be kept to a minimum and thereby reduce cash
requirement for the business.
Production control : It is an extremely complex area especially in
factor automation. Production should respond quickly to changes in
demand and other circumstances. This requires accurate up-to-date
information which should also be timely. On-line systems help to get
data quickly enough to influence current events. A computer can make
machine loading, materials control, machine utilization etc. A computer
is more efficient because of its ability to make complex calculations and
shift data quickly and accurately.
Labour control : Some of the information used in the control of labour
can be obtained from the payroll and personnel records. An analysis of
labour hours for idle time, sickness and absence, can aid forecasting
future requirements. Results of analysis help to highlight these problems
accurately and actual performance can be measured quickly against
planned performance. Reports for the shop-floor manager aid control of
routine operations and can help better utilization of manpower.
Network analysis : Network analysis is used for planning and control of
complex projects. Examples are the building of a factory, the installation
of new plant and the manufacture of an aircraft or ship. A model is used
to show each stage in the project and its dependence on other stages.
When the necessary data have been supplied the program produces a
Stock control
Production control
Labour control
Network analysis

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plan for the management. The plan can be quickly modified by the
program in the light of actual progress, and revised plans produced at a
short notice. The program also indicates the interdependent activities
that take longest time to complete and could hold up the project.
Linear programming : This is used to find the optimum solution which
maximizes profits or minimizes costs. A considerable amount of data are
supplied to construct a computer model. The computer has the storage,
capacity and the speed to calculate and evacuate every feasible solution
and thus to find the best one. A manager, dependent on human resources,
cannot do this as the time required for calculations would be prohibitive.
Financial modeling : A model is constructed for the company's fiancees
comprising of its resources, income and expenditure. The model is used
to simulate the effects of different policies. An example is the forecast of
the results of different investment policies. It is possible by a series of
computer runs, with variations of the basic assumptions to obtain a
forecast of the likely effects of alternative policies. The usefulness of the
computer lies in its high speed, which enables it to execute instructions
quickly.
Scientific, Engineering and Research Applications
These applications include the use of computer for complex
mathematical calculations, analysis of data of various nature, design
analysis and control of physical systems etc. Here the main emphasis of
data processing is research and development for scientific, engineering
and industries applications. Few areas are described below.
Weather-forecasting : Weather-forecasting demands vast
computational powers. This is an area which requires the super-
computers.
Mathematical and statistical analysis : These analysis require large
calculations and solutions of mathematical and statistical problems. The
applications include research in physics, chemistry, geology,
archaeology, medicine, astronomy, social science etc. Some commercial
problems have mathematical bias, and require mathematical analysis to
determine the optimum use of resources.
Design work : Computers can be used as a design tool in engineering
and other disciplines. CAD (Computer Aided Design) is used in
electronic, electrical, mechanical, aeronautical, civil engineering,
architecture and many other disciplines.
Linear programming
Financial modeling
Weather-forecasting system
analysis
Mathematical and statistical
analysis
Design work

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Medical applications : There are numerous applications of computers
in medicine. Some examples are discussed below.
Computer can be used as an aid to medical research by analyzing data
produced from experiments and to diagnosis. The computer acts as a
large bank of data about known medical conditions. Once a computer
systems has been set up by medical experts an ordinary doctor can be
taken through a question and answer session by the computer until a
correct diagnosis is made.
Computers can be used to hold details of the patients. Microcomputer
systems are now used for this purpose in increasing numbers.
Computerized health records can be used by medical officers, health
visitors, and researchers.
Education : Computers are used extensively as a part of study in
computer science itself. They are used as way of aiding the
understanding of a wide variety of other subject. The computer can
provide instructions and ask questions. This kind of activity is called
computer-aided Learning (CAL) or computer-aided Instructions (CSI).
Computers are also used for a number of other applications in education;
examples are: marking of multiple choice examination papers and
processing examination results.
Manufacturing : Some examples of use of computers in manufacturing
are: stock and production control, engineering design etc. The industrial
design, manufacturing and testing processes are becoming increasingly
computerized. The terms CAD, CAM (Computer-Aided Manufacture)
and CADMAT (Computer-Aided Design Manufacture and Testing) are
familiar words in industries now.
Robots : The word "robot" comes from a Czech word whose meaning is
"to lablour". For many years the term “robot” was associated with
science fiction rather than science fact. That association has changed
now.
The basic difference between industrial robots and other automated
machines is that a robot can be programmed to carry out a complex task
and be reprogrammed to carry out another complex task. A complex task
is a series of actions involving mechanical manipulations.
The majority of robots in current use, are "blind" and lack a "sense of
touch". It is hoped that the next generation of robots will be able to find
and locate objects or detect their presence by touch and vision.
Medical application
Education
Manufacturing
Robots

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2.3 Other Applications
Computers are used for a variety of applications and there are some
applications that do not fall into either of the applications mentioned
above. Some of these applications are discussed below.
Expert Systems
An expert system is a program package that can perform the function of
a human expert. Some of the initial expert systems were used for
medical diagnosis. A medical consultant, assisted by his staff, takes part
in a lengthy exercise in which both the knowledge and the decision-
making procedures are transferred to the computer. As a result the
computer can ask questions and draw conclusions from the answers and
a junior doctor, aided by the computer, could be as expert as the
consultant.
There are many applications for expert systems company law,
investment, finance and personnel management etc. Expert systems
normally have the following features :
• An organized base of knowledge in the form of a database.
• A user interface to support diagnostic discussions with the user.
• A facility to hold details of the consultation.
• An inference engine, that is a software, which can use the
knowledge base and current consultation to formulate further
questions or draw conclusions from actions.
• A knowledge acquisition system, to update the knowledge base.
Although the basic components of an expert system are bound to very
from one discipline to another the basic structure is the same. Therefore,
an established method for developing an expert system is to build the
system from a standard non-application-specific basic system called a
shell. It is possible to purchase a complete expert system or merely a
shell from which an expert system can be created.
The user of the expert system sits before a PC or and takes part in a
question and answer session in which data about the problem is typed in.
At various stages during the session, or at the end, the system makes an
assessment of the problem and recommends actions.
Expert system package are not confined to large computers. Several are
available now for personal computers.
Expert systems
Features of expert systems

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Intelligent Knowledge-Based Systems (IKBS)
These systems appeared on the market recently. They are intended to
provide an expert consultative service to management and are also called
"expert systems".
A typical system interactive and contains a large database. The system is
programmed with a decision-making strategy developed by careful
consultation with experts in the field. The user takes part in a question
and answer session in which data about the problem is through the
keyboard. At the end of the session the system makes an assessment of
the problem and suggests actions.
Application Packages
It use of an application package is an alternative to developing of
programs. Many small organizations cannot afford to employ a
programmer, and individual users, are not capable of writing programs.
As an alternative, many firms and individuals purchase programs. An
application package generally include a full description of the operation
of the program, user instructions and documents. There are many large
organizations which find it more economic to purchase application
packages rather than writing their own applications. Some advantages
connected with the use of applications packages are :
• No need to employ a programmer for program development.
• The program is ready immediately.
• The developer of the application package employ skilled
programmers.
• It is possible to get help or share experience with other users of
the package.
There are, however, some disadvantage in the use of application
packages as compared with program development. The most important
are :
• The programs may be too general and not readily matched to the
needs of the user.
• It may be difficult to adapt the program to the changing needs
and growth of the user’s application.
Intelligent Knowledge-Based
Systems (IKBS)
Application Packages

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2.4 Exercise
a. Mention the common areas of applications of computers.
b. List the operations incorporating office automation.
c. Explain the terms : CAD, CAL, IKBS, ROBOT, E-mail and
applications package.
d. Give the advantages of using applications packages.
a. What do you understand by office automation? Discuss the common
jobs for office automation.
b. Discuss, with examples, the importance of computer for
management applications.
c. Discuss scientific, engineering and research applications of
computers.
d. What is an expert system? Explain its characteristics.

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Lesson 3: Impact of Computers on Society
3.1 Learning Objectives
• understand the interaction between computers and society
• define information technology
• name the major causes of dependency on computers
• appreciate scope and influence of computers
• identify future computer applications
• identify illegal and controversial computer-related issues
• understand the challenge for the future computer applications.
3.2 Computers and Society
The role of computer in society is a complex issue and this lesson
highlights some important ones only. Modern society relies on
automation and on automated handling, storing and processing of
information. Efficiency of production of wealth depends heavily on
various kinds of automation and computers are used to automate
methods for processing information. Apart from information processing,
computers play important role in many other areas of industry.
Storage, processing and dissemination of information play a very
important role in modern society. Computers telecommunications, data
and computer communications contribute tremendously for these
activities. Computers and electronic communications are getting closer
and closer every day. Computers, electronic communications and other
technologies associated with automation come under the general tern of
information technology. Information technology influences our lives and
its impact on individuals organizations and society is increasing day by
day.
Major technological innovations generally affect the lines of individuals.
New inventions lead people and society to view world through new eyes
and to accept new values. Apart from benefits, many technological
advances have harmful effects in society. This lesson fugues on the
values of technological advances of computers and information
technology ion society.

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Causes of Dependence on Computers
Present society is heavily dependent on computers and their applications.
Among others, the two major causes for this dependence are :
• Ability to calculate and computer
• Handling and processing of information.
Computer can perform calculations at a speed beyond human ability and
with accuracy and consistency which people can not match. Some of the
knowledge we process today would be unknown without the fast
computational ability of computers. The rapid social, economic cultural
and technological changes cannot be imagined without the fast
computational speed of preset day computers.
Ability to record and store information, process that information at high
speed, and reproduce the information in a variety of ways makes the
computers indispensable for modern society. Information is generated in
such a volume that it is impossible to handle information by
conventional methods.
Present world is so much dependent on computers that if they could be
swept away overnight, the airlines communication and financial
operations of most part of the world would collapse. These are many
more examples like these. It is not possible for average persons to
appreciate the direct and indirect impact of computers in society. But it
is true that computers have penetrated human society for more deeply
than the overage persons can realize.
Impact of Computer
Commerce, industry, education, administration, transportation,
communication etc. and many other organization, professions and
individuals depend on one way or another on computers and their
applications directly or indirectly. Impact of computer on few important
areas of human activities are discussed briefly.
Commerce : Banking, insurance, credit companies, airlines shopping
centres and many business concerns need computers for their daily
operations. They form the majority users of computers. Financial world
cannot survive in the existing form without assistance from computers.
Commerce needs quick communication and pouch day businesses
depend much on computer communications, computer bulletin boards, e-
mail and the Internet. Impact of such items can only increase in the
future. Financial success of a nation cannot be imagined without the
successful use of computers in business activities.
Impact of computer
Causes of Dependence on
computers

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Industry : Many industries such as the steel, chemical and oil
companies rely on computers for the actual control of plant processes.
This trend can only increase, in the future. Microprocessors are used in
harsh environments: in extremes of cold and in dirty and noisy
atmospheres. Many of the tasks involved in assembly work as in the
motor-car, washing machine and television industries are undertaken by
processes controlled by microcomputers.
Many sophisticated industrial, control and manufacturing processes
cannot be imagined without microcomputer boards, embedded
microprocessors and robots. Computer aided designing (CAD),
computer aided manufacturing (CAM) and computer aided design
manufacture and testing (CADMAT) and popular for many industries.
Education : In future much of the traditional teaching will be performed
with the help of computers. This form of teaching is known as computer-
assisted instruction (CAI) and computer-assisted learning (CAL).
Technically this is possible and indeed exists in a some countries. In the
institutions of higher education the computer has become an
indispensable tool for undergraduates and postgraduates for arts,
science, business, technology etc. Many of the current projects
undertaken by postgraduates would be impractical without computers.
Future institution of learning will have facilities to select programs,
courses and mentors from leading institutions, libraries, museums and
technical institutions throughout the world. In future interactive
multimedia, electronic libraries and the information superhighway will
play a major role in providing a range of interactive courses and
services. Thus the future educational institutions should provide virtual
learning environment, besides a physical campus. Such institution of the
future may be termed as virtual institutions of learning.
Administration : Many of the administration tasks are profaned by
computers. Word-processing, spreadsheet analysis, database
management, pay roll, automatic order processing are some examples.
Interpersonal and inter-office messaging, which is popularly known as
electronic mail, is essential for quick and effective way of
communication for administrative. Videoconferencing is a common
place for official and administrative activities in some nations.
Automatic offices of the future will be dependent on computers,
electronic communications and computer networking.
Transportation : Sea and air transportations of today relay on
computers and computer communications. Many road transport
companies in advanced countries use cellular and satellite
communications to prepare optimized routes for the vehicles and for
Impact of Education
Virtual institutions learning
Administration

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sending instructions to the drivers and operators. Computer controlled
traffic systems provide efficient management of traffic in some major
cities of the world. Without computers air traffic control would be
virtually impossible at the busy airports. Ships in the congested shipping
lanes (such as the English channel) are regulated by computer
communication through satellites.
Networks and Communications : Information networks provide
services to end users through communication links between
microcomputers. The major components of computer networks are the
central computer, database, the communication links and
microcomputers. The end users desiring services can access the database
in the central computer. The databases contain data and screens of
information that are presented to the users. A great variety of wide area
networks and databases already exists for end users. The Internet which
is the network of networks wrap around the world and it is the biggest
source of information and the most popular means of communication for
education, research, business, entertainment and many other social and
cultural activities. The future telephone will be incorporated into the
microcomputer and one will not only hear but also see the person on
other end of the line. The users will be able to pass data and information
back and forth as if they were sitting at the same table.
Other Professions : Law, medicine, libraries, armed forces and many
other professions and working environments make use of computers and
therefore depend upon computers. A good percentage of children at
school will be working directly or indirectly with computers after they
leave school. This emphasizes computer literacy and computer education
in the society.
Individuals : Even if we are not directly concerned with computing in
our everyday work, as individuals we are affected by them in one way or
other. Air passengers, hospital patients, the shoppers in large store are
some of the people for whom computers process information. Tax,
electricity, telephone or gas bills are processed by computers and
salaries are calculated by computers. Indeed, it is difficult to find anyone
who in some way or another does not depend on computers.
Controversies
Society depends very much upon the computational and information
processing skills of computers. The benefits of using computers are
obvious and have been discussed above. However computer revolution
has generated intense controversies. Some of these heated controversies
are listed below :
Transportation
Controversies
Networks and Communica-
tions
Other Professions
Individuals

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• Privacy and misuse of personal information
• Monitoring data on job activities
• Electronic fund transfer and cashless society
• Effect of automation on job
• Computer crimes.
Privacy : A great deal of data about individuals are stored in computers,
and the trend to store such data is increasing. Some of the data are of
personal or private nature and there is a natural concern that they should
not be misused. Some countries have passed or are about to pass the data
protection act and create data protection authority stoop the misuse of
personal data and to cheek violation of privacy.
Computer Monitoring : In computer monitoring, computer
continuously gather and assimilate data on job activities to measure
performance of the employees. Computer monitoring has proved itself a
useful tool for increasing productivity. However, workers usually
complain that being constantly observed and analyzed by a computer
automatically add unnecessary stress to them.
Casheless Society : In electronic fund transfer (EFT) money is
transferred electronically from bank to bank and from account to account
by computers. Use of automatic teller machines (ATM) and payroll
transfer systems is increasing. Some banks offer home banking services
through their computers. Money may be eliminated in future remitting in
a casheless society! It has some advantages, but the critical issue is the
misuse of personal information as the system needs every thing from a
person's life style to his or her location to be monitored.
Jobs and Unemployment Issues : Computers usually affect the work of
staff within the organization. As a result some jobs may be created and
some may be lost. This creates a demand for training and retraining.
Loss of jobs due to computerization gives rise to alarm. However, only a
very small proportion of the unemployment is directly caused by new
technology. In certain applications jobs likely to be lost are: some office
and factory jobs.
Whether job losses result in permanent unemployment is another matter.
It depends on the process of reemployment and retraining of the affected
labour.
Computer Crimes : There are many types of computer crimes.
However, three aspects computer crime are often reported and deserve
attention because of their social importance. They are :
• Hacking and Computer fraud
• Computer viruses
• Copyright piracy.
Computer Crimes
Privacy
Computer Monitoring
Casheless Society
Jabs and Unemployment
Issues

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Hacking
The term "hacker" identifies a programmer who worked in an skillful but
illegal way. The name has become associated with individuals who make
a hobby of making unauthorized access to computer systems. This
antisocial behavior often leads to loss and inconvenience to the
individuals. Legislation has been passed in many countries to make
hacking illegal. The technique used by hackers to bypass system security
are similar to those used by individuals concerned in computer fraud.
Computer systems should be made as safe and secure as possible against
hacking, fraud and viruses.
Computer Virus
A computer virus is a program which attaches itself to another program
on a system. It replicates itself and causes undesirable effect on the
programs it becomes attached to. To parallels with the way in which a
biological virus affects other organisms. Computer viruses usually infect
system by disks which have been infected. When a virus infected
program is run the virus, modified its host, and also replicate itself.
Some viruses are merely annoying. Others cause data to be corrupted or
deleted. There are many virus detection and protection packages in use.
Today Kaspersky, Norton, Quick Heal are the popular antivirus software
Copyright
Software piracy is the use of unauthorized copies of software. It is like
any other breach of copyright and the individuals responsible can face
stiff penalties. Many countries passed regulation to prevent software
copy right piracy.
Future Challenge : The outlook for innovative and beneficial computer
applications is very bright. The area application that are socially,
economically and technologically feasible is expanding steadily. Use
and expansion of computer networks and on-line database will
tremendously influence communications, office automation,
manufacturing, retail and financial services, publishing, transportation,
health care, government and administration, education, entertainment
etc. Neural networks and artificial intelligence will eventually
revolutionize computing. The fifth generation computers possessing
artificial intelligence may be available by the end of the twentieth
century.
Computers can improve the quality of lives and contribute to improve
our economy. The challenge is to harness the power of computers and
direct it to the benefit of society. The poor countries find it difficult to
invest money for expanding computer education and computerization.
Computer Virus
Future Challenge

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However, careful steps are essential to use computers to improve
productivity and socio-economic condition of our society.

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3.3 Exercise
a. What are the main components of information technology?
b. Briefly discuss the influence of computers on (i) education, (ii)
communication, (iii) commerce, and (iv) industry.
c. Briefly discuss the influence of computer networks on society.
d. Explain the term cashless society and virtual institution of
learning.
e. List some heated controversies of wide-spread use of computers.
f. What is a computer crimes? List common computer crime.
g. Write short notes on (i) computer virus, (ii) hacking and (iii)
copyright piracy.
a. Discuss the future influence of information technology in society.
b. Discuss critically : Computers are both asset and a danger to the
society.
c. What developments are likely to occur in computer technology in
the foreseeable future? How will such developments influence
Bangladesh society?
d. Discuss how the nature of jobs should change by the influence of
information technology.
e. Discuss critically how computers are changing activities in the
field of (i) education, (ii) commerce, (iii) industry, (iv)
communication, and (v) transportation.
f. Write a short essay on computer crimes.
g. Explain virtual learning environment and virtual institution of
learning.

Applications
187
Lesson 4: General Maintenance
• avoid repair by preventive maintenance
• know different factors which affect computer
• diagnose general and common problems
• take precaution against virus
• maintain general protection.
4.2 Factors Affecting Computer
Common physical factors affecting computers are heat, dust, water,
corrosive agents, power line problems and magnetism. Each of them may
cause the breakdown of the computer system. Effect of these are given
below.
Heat
It is one of the most destructive factor that damages computers. An
electronic device disciples about 50% of its power as heat energy. Heat
should be removed as quickly as it is produced. Heat can be checked by
installing fan and running the computer in a safe temperature range.
Ambient temperature range for computers should be between 600
F and
85 0
F. Another source of heat is rays of sun. A computer should be
installed in a cool place away from sun rays.
Dust
Dust acts as a thermal insulation on the board. It prevents heat to radiate
from inside the computer. A blower with compressed air can be used to
remove dust. A dust free cloth wetted with water should not be used to
clean the circuit board. Moreover, dust can clog air intake area to power
supply or hard disk drive and space between the floppy disk drive head
and the disk. To audio these problems a dust cover should be used when
the machine is not used. Smoking should always be avoided near
computers. The printers should be periodically cleaned by blowing out
paper dusts.
Factors Affecting Computer
Heat and Dust

Computer Basics
188
Water
Water or liquid should not be allowed near computers and drinking
should be avoided near computers. In case of accidental spilling of water
or liquid on the computer or keyboard, the computer should be
disassembled, cleaned, dried and the reassembled.
Corrosive Liquids
Salt in sweat and cleaning fluids are very corrosive. Oxidation of circuit
contacts is another problem. When a connector becomes oxidized, it
does not function properly. Tea and coffee contain tannic acids,
carbonated liquids have carbonic acid. Drinking tea or coffee should be
avoided near computers.
Powerline Problems
Good and clean power supply is the most important environmental factor
for a computer. Common power line problems are : brownouts,
blackouts, transients and noise. Brownouts are sags for lower voltages,
blackouts are the total loss of line voltage, transients are large potentially
damaging spikes of voltages or current and noise is any unwanted
electrical disturbance in the power line. There are two kinds of
approaches to remove powerline problems. They are : condition the
power being supplied and providing an auxiliary or backup power
source. Voltage stabilizers are normally used to condition electrical
power against brownouts, transients and noise. The uninterrupted power
supply (UPS) stores energy when the line voltage is present and then
delivers power to the computer when a blackout occurs. The UPS should
be used when it is important to save date and files against total loss of
power.
Magnetism
Magnetism causes permanent loess of data on hard or floppy disks.
Magnetic is field is present around phones, electric motors, stereo
speakers, cathode ray tubes (CRT) etc. Stray elector-magnetism like
radiated elector-magnetism interference (EMI), power line noise (due to
overvoltage, undervoltage, transient spikes and surges) and electrostatic
discharges can cause problems for computer.
Water
Corrosive liquid
Powerline problems
Elector-magnetic Interference
(EMI)
Brownouts, Blackouts,
Transients and Noise

Applications
189
Computer Virus
A computer virus is a piece of software which infects data or disks and
has multiplication capability of itself. They affects computers by
deleting files, corrupting screen displays, corrupting data, slowing down
operation of a system, displaying unwanted messages etc. A
sophisticated virus can spread undetected for a long time. A boot virus
attires boot sector of a disk. Viruses affects files with extension EXE,
COM, SYS, DRV, OVR, OVI, BIN, Some common viruses are C
Barium, Jerusalem, Stone (Marijuana), Dhaka virus, Vienna, April First,
Norton, Quick Heal, Kaspersky.
There are many antivirus programs which detect clean and prevent virus.
Some antivirus programs are : Norton Antivirus (NAV), Norton, Quebec
heal, Kaspersky Central Point Antis Virus (CPAV), Toolkit etc. For
virus prevention, virus reporting disk with a copy of antivirus program is
used to reboot a system to disinfect viruses. CD, Pen drives, other disks
should not be used unless they are checked or reformatted. Backups of
data should be maintained against virus attacks.
Repair and Maintenance
To avoid servicing cost one should perform the preventive or routine
maintenance of the computers. But in case of complicated failures of
computers the experienced engineers or the suppliers should be
contacted.
Common factors affecting computers are : heat, dust, water, power-line
problems, magnetism, corrosive liquids etc. Temperature of the
computer room should be between 65 0
F and 85 0
F. The room should be
dust free and drinking near computers should be avoided. A computer
should be protected against static electricity and magnetism. Stabilizers
or uninteruptable power supplies should be used against power-line
problems. Antivirus programs should be used to scan, detect, clean and
prevent computer uses.
Computer Virus
Routine and Maintenance

Computer Basics
190
4.3 Exercise
1. Find True / False
a. Blower is used to remove heat.
b. Dust usually don't make any harm to computer.
c. Salt in sweat helps to oxidize the connection in circuit board.
d. Magnetic field can damage hard disk data.
e. Antivirus programs can only prevent computer viruses.
a. List the Physical factors that affect the performance of a computer.
b. Explain the terms blackout, brownout transient and EMT.
c. Distinguish between a stabilizer and on UPS.
d. Give advantages of preventive maintenance.
a. Explain how dust affects the performance of computers. What
precautions should be taken against dust?
b. What is a computer Virus? How does it affect the computer
systems? Discuss virus protection measures.
c. Why clean supply of power is important for computers? Explain
the power line problems that affect the computes.
d. What measures should be adopted to prevent computers against
power line problems?

Applications
191
Lesson 5: Selection of Microcomputers
• select component of a microcomputer
• select microprocessors for microcomputers
• choose secondary memory (hard disk and floppy disk, pen drive, CD)
• select monitors and cards for monitors
• choose operating system and application software.
Components of Microcomputer
Selection of a microcomputer means selection of different components
of a micro-computer. Most important components are: processor,
memory (cache, hard disk and floppy disk, pen drive, CD) monitor,
operating system and application software.
Choosing a Processor
The microprocessor is the central component of a microcomputer and it
determines it main features. It is also a major factor in determining the
computer's price as the other components of the computer must be
compatible to it.
An 8088 or 8086 processor was used in early XT computers. These are
obsolete now. The past few years have seen the gradual development and
uses of 80286, 80386, 80486 and upper series processors. At present the
Pentium, Quard core, Dual core processors are common for most
microcomputers. This processor provides very good performance and is
usually required for network servers and CAD (Computer-Aided Design)
workstation.
For selecting the PC, it is important to consider the role of the computer,
both initially and in the longer term. It is always better to buy high
configuration, high-performance, bare-bone systems having upgrade
potential.
Main Memory
Memory chips have become inexpensive in recent years and tendency of
using larger programs are increasing. New versions of programs seem to
grow exorbitantly requiring megabytes of disk space and large amounts
of main memory. Thus the more main memory, the better. When buying
a computer it is important to look out for sockets on the motherboard for
Components of Micro-
computer
Processor
Main Memory

Computer Basics
192
extra an expansion to RAM, otherwise adding memory later becomes
relatively expensive.
Program manufactures usually give the minimum requirements for the
programs. Below the specified limit, a program won’t run. For
satisfactory operation, considerably more memory is almost always
necessary. However, determining the actual amount requires some
experience with the particular program. It is better to check with the
dealer, consult computer journals, or ask an experienced user.
In almost every PC, there is some facility to expand the main memory
PC motherboard manufactures usually equip their products with special
sockets and sell standard memory modules for memory expansion.
Selecting Hard Disk Drives
As the data transfer rates have been standardized, the essential selection
criterion should be the smallest possible average access time. IDE and
EIDE disks were once hot sellers and are still quite popular. However,
since there are better alternative now, the older type of disks should be
bought for existing computer and controller.
The special properties of the SCSI interface make it the model of choice
now because of speed and higher disk capacity. Single-user computers
may be equipped with an IDE disk. This disk combines high speed and
advanced drive technology at a reasonable price. Attention should be
paid to the average access time. Access times greater than 20 ms are no
longer attractive. The controller and the hand disk must match.
The size for the hard disk depends on the software and the type of work
to be done. The size should be minimum about 1GB. Sufficient space
should be available for normal office applications at this capacity.
Programs that use graphic interfaces often require large capacity.
Floppy Disk Drive
The 3.5-inch floppy disks are smaller convenient and robot and they
have a higher storage capacity than 5.25-inch floppy disks. A computer
with a single drive, should have a 3.5-inch with 1.44MB capacity. For a
computer with a 5.25-inch drive, there is no problem finding software on
this type of floppy disk. In a computer with an 80286 or higher
processor, the drive should handle 1.2 MB floppy disks.
Difference can be observed between the 3.5-inch drives of various
manufactures. The mechanism for ejecting the floppy disks is poorly
designed in some disks. Inserting and ejecting a floppy disk should be
tried before buying a disk drive. When the floppy disk drive is opened,
the disk should come out just far enough to be removed easily. The
Selection of Hard Disks
Floppy Disk Drive

Applications
193
loudness of the drive should also be checked. Some drives make noise
particularly when formatting a floppy disk.
USB Flash Drive
A USB flash drive is a small storage device shaped like a pen with built-
in data storage that connects to a computer by a USB (Universal Serial
Bus) port. USB flash drives also known as thumb drives, jump drives,
pen drives, key drives or simply USB drives. Flash drives can be written
and rewritten to an almost unlimited number of times similar to hard
drives. Now, most flash drives have a storage capacity from 8 GB to 64
GB. The largest one is a USB 3.0 flash drive with 1TB (1024 GB)
capacity. Flash drives have completely replaced floppy drives for
portability, large storage capacity, inexpensiveness and life-long
warranty.
Selecting Monitor
The video card and monitor form a unit and they must match. This
applies not only to the type (a VGA card for a VGA monitor) but also
for the technical characteristics.
Recommendations for monitors are similar to those for video cards.
Basic equipment today should be at least a VGA monitor with a
resolution of 1024 × 768, and a refresh rate greater than 60 Hz, in
noninterlaced mode. Higher resolution are important for bigger
monitors.
Applications dictate the need for colour or monochrome monitor. Color
is usually not required for business programs and office applications.
But graphics applications and games do require a colour monitor.
A multifrequency monitor can adapt to many horizontal frequencies, and
can be connected to a video card with a different line frequency.
However, a fixed-frequency monitor that is well matched to the
corresponding video card is less expensive.
Monitor quality can be imagined by displaying dark letters against a
light background. The display should not flicker. Attention should be
paid to the lowercase letters e, s, and a. There should not be a ring
around the individual letters.
It is good to have a demonstration of the monitor. Several hours of work
at an unsuitable monitor can bring on a headache for the user.
The interaction between the video card and the screen or monitor is
important. SVGA cards and their corresponding monitors have become
Monitor
What to Buy?
Pen Drive

Computer Basics
194
inexpensive now and the older graphics standards should not be
recommended. A SVGA card can operate both a monochrome and a
colour screen. LCD monitor is new available and it is very popular for
use.
Any video card should have a refresh rate of more than 60 Hz in
graphics mode. The advanced graphics applications require refresh rates
of 70 Hz.
Choosing Operating System
MS DOS is still used for PCs. With an 80286 or better processor,
“Windows” has become popular now. Consequently there is no trouble
finding suitable software, programs for Windows.
The multitasking properties of Windows cannot be used unless an
80386X processor is used. Additionally, less than 4Mb of main memory
and a fast hard disk make working with Windows really a fun. Windows
XP is also becoming popular now in our country, it requires 1 GB of
RAM for comfortable operation.
Application Software
Current computer magazines should be consulted to gather information
about a given program before buying it. There are special interest
magazines dealing only with freeware and shareware program. Dealers
and the forums of on-line services, if available, should be consulted for
information. Application areas and the extent of use of the program
should be considered when selecting software. Sometimes public domain
or shareware products suffice for private use. For businesses, a
commercial product is generally preferred, so that when problems do
occur, it can be removed quickly. It is, of course, a great advantage if a
knowledgeable dealer is there to help immediately. However, the
software manufacturer is ultimately responsible for supporting its own
product.
Some publishing houses produce market overviews of software
programs. PC Magazine, PC World, and Info World and some Bengali
computer magazines are good source of such information. In Some
magazines short descriptions of the software and hardware the vendor’s
addresses, and prices, all classified by type of applications are provided.
Also some books are available for choosing the right program for an
application.
Operating System

Applications
195
Selection Chart
In order to check the main features of a microcomputer or for selection a
microcomputer simple chart can be designed. Filling the blanks in the
chart with specifications provided for the computer can help to compare
and select microcomputers.
Manufacture
Brand
Processor
Mother board
BUS speed
RAM
Optical storage
Cache memory
Bus Architecture
CD-ROM
Hard Disk
Display Adapter
Casing
Monitor/ Display
Network capability
Other adapters
Number of slots
Operating System
Keyboard
Casing
Fig.8.1 Microcomputer selection chart/ Specification.
Once software is selected several dealers should be asked about it. There
are considerable price difference, up to 50 percent, in extreme cases.
Selection Chart

Computer Basics
196
4.3 Exercise
a. Which are the most widely used processors?
b. How can you increase memory of your computer?
c. What is the advantages of Windows over DOS?
a. What are the considerations for selecting a hard disk?
b. How can you purchase software?
c. How will you select an operating system for your computer?
d. Discuss the criteria for selecting a monitor and a printer.
e. Discuss the importance of microcomputer selection chart or
specification. Prepare a selection chart/Specification for
purchasing a computer for office use.

Applications
193
Lesson 5: Selection of Microcomputers
• select component of a microcomputer
• select microprocessors for microcomputers
• choose secondary memory (hard disk and floppy disk, pen drive, CD)
• select monitors and cards for monitors
• choose operating system and application software.
Components of Microcomputer
Selection of a microcomputer means selection of different components of
a micro-computer. Most important components are: processor, memory
(cache, hard disk and floppy disk, pen drive, CD) monitor, operating
system and application software.
Choosing a Processor
The microprocessor is the central component of a microcomputer and it
determines it main features. It is also a major factor in determining the
computer's price as the other components of the computer must be
compatible to it.
An 8088 or 8086 processor was used in early XT computers. These are
obsolete now. The past few years have seen the gradual development and
uses of 80286, 80386, 80486 and upper series processors. At present the
Pentium, Quard core, Dual core processors are common for most
microcomputers. This processor provides very good performance and is
usually required for network servers and CAD (Computer-Aided Design)
workstation.
For selecting the PC, it is important to consider the role of the computer,
both initially and in the longer term. It is always better to buy high
configuration, high-performance, bare-bone systems having upgrade
potential.
Main Memory
Memory chips have become inexpensive in recent years and tendency of
using larger programs are increasing. New versions of programs seem to
grow exorbitantly requiring megabytes of disk space and large amounts
of main memory. Thus the more main memory, the better. When buying
a computer it is important to look out for sockets on the motherboard for
Components of Micro-
computer
Processor
Main Memory

Applications
194
extra an expansion to RAM, otherwise adding memory later becomes
relatively expensive.
Program manufactures usually give the minimum requirements for the
programs. Below the specified limit, a program won’t run. For
satisfactory operation, considerably more memory is almost always
necessary. However, determining the actual amount requires some
experience with the particular program. It is better to check with the
dealer, consult computer journals, or ask an experienced user.
In almost every PC, there is some facility to expand the main memory
PC motherboard manufactures usually equip their products with special
sockets and sell standard memory modules for memory expansion.
Selecting Hard Disk Drives
As the data transfer rates have been standardized, the essential selection
criterion should be the smallest possible average access time. IDE and
EIDE disks were once hot sellers and are still quite popular. However,
since there are better alternative now, the older type of disks should be
bought for existing computer and controller.
The special properties of the SCSI interface make it the model of choice
now because of speed and higher disk capacity. Single-user computers
may be equipped with an IDE disk. This disk combines high speed and
advanced drive technology at a reasonable price. Attention should be
paid to the average access time. Access times greater than 20 ms are no
longer attractive. The controller and the hand disk must match.
The size for the hard disk depends on the software and the type of work
to be done. The size should be minimum about 1GB. Sufficient space
should be available for normal office applications at this capacity.
Programs that use graphic interfaces often require large capacity.
Selecting Monitor
The video card and monitor form a unit and they must match. This
applies not only to the type (a VGA card for a VGA monitor) but also for
the technical characteristics.
Recommendations for monitors are similar to those for video cards.
Basic equipment today should be at least a VGA monitor with a
resolution of 1024 × 768, and a refresh rate greater than 60 Hz, in
noninterlaced mode. Higher resolution are important for bigger monitors.
Selection of Hard Disks
Monitor

Applications
195
Applications dictate the need for colour or monochrome monitor. Color
is usually not required for business programs and office applications. But
graphics applications and games do require a colour monitor.
A multifrequency monitor can adapt to many horizontal frequencies, and
can be connected to a video card with a different line frequency.
However, a fixed-frequency monitor that is well matched to the
corresponding video card is less expensive.
Monitor quality can be imagined by displaying dark letters against a light
background. The display should not flicker. Attention should be paid to
the lowercase letters e, s, and a. There should not be a ring around the
individual letters.
It is good to have a demonstration of the monitor. Several hours of work
at an unsuitable monitor can bring on a headache for the user.
The interaction between the video card and the screen or monitor is
important. SVGA cards and their corresponding monitors have become
inexpensive now and the older graphics standards should not be
recommended. A SVGA card can operate both a monochrome and a
colour screen. LCD monitor is new available and it is very popular for
use.
Any video card should have a refresh rate of more than 60 Hz in graphics
mode. The advanced graphics applications require refresh rates of 70 Hz.
Choosing Operating System
MS DOS is still used for PCs. With an 80286 or better processor,
“Windows” has become popular now. Consequently there is no trouble
finding suitable software, programs for Windows.
The multitasking properties of Windows cannot be used unless an
80386X processor is used. Additionally, less than 4Mb of main memory
and a fast hard disk make working with Windows really a fun. Windows
XP is also becoming popular now in our country, it requires 1 GB of
RAM for comfortable operation.
Current computer magazines should be consulted to gather information
about a given program before buying it. There are special interest
magazines dealing only with freeware and shareware program. Dealers
and the forums of on-line services, if available, should be consulted for
information. Application areas and the extent of use of the program
should be considered when selecting software. Sometimes public domain
or shareware products suffice for private use. For businesses, a
What to Buy?

Applications
196
commercial product is generally preferred, so that when problems do
occur, it can be removed quickly. It is, of course, a great advantage if a
knowledgeable dealer is there to help immediately. However, the
software manufacturer is ultimately responsible for supporting its own
product.
Some publishing houses produce market overviews of software
programs. PC Magazine, PC World, and Info World and some Bengali
computer magazines are good source of such information. In Some
magazines short descriptions of the software and hardware the vendor’s
addresses, and prices, all classified by type of applications are provided.
Also some books are available for choosing the right program for an
application.
Selection Chart
In order to check the main features of a microcomputer or for selection a
microcomputer simple chart can be designed. Filling the blanks in the
chart with specifications provided for the computer can help to compare
and select microcomputers.
Manufacture
Brand
Processor
Mother board
BUS speed
RAM
Optical storage
Cache memory
Bus Architecture
CD-ROM
Hard Disk
Display Adapter
Casing
Monitor/ Display
Network capability
Other adapters
Number of slots
Operating System
Keyboard
Casing
Fig.8.1 Microcomputer selection chart/ Specification.
Selection Chart

Applications
197
Once software is selected several dealers should be asked about it. There
are considerable price difference, up to 50 percent, in extreme cases.
4.3 Exercise
a. Which are the most widely used processors?
b. How can you increase memory of your computer?
c. What is the advantages of Windows over DOS?
a. What are the considerations for selecting a hard disk?
b. How can you purchase software?
c. How will you select an operating system for your computer?
d. Discuss the criteria for selecting a monitor and a printer.
e. Discuss the importance of microcomputer selection chart or
specification. Prepare a selection chart/Specification for
purchasing a computer for office use.

computer Unit 8

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