SYSTEM CONCEPTS
A system can be simply defined as a group of
interrelated or interacting elements forming a unified whole. Many examples of
systems can be found in the physical and biological sciences, in modern
technology, and in human society. Thus, we can talk of the physical system of
the sun and its planets, the biological system of the human body, the
technological system of an oil refinery, and the socioeconomic system of a
business organization.
A system is a group of interrelated
components working together toward a common goal by accepting inputs and
producing outputs in an organized transformation process. Such a system
(sometimes called a dynamic
system) has three basic interacting components or functions:
·
Input involves
capturing and assembling elements that enter the system to be processed. For
example, raw materials, energy, data, and human efforts must be secured and
organized for processing.
·
Processing involves
transformation process that convert input into output. Examples are a manufacturing
process, the human breathing process, or mathematical calculations.
·
Output involves
transferring elements that have been produced by a transformation process to
their ultimate destination. For example, finished products, human services, and
management information must be transmitted to their human users.
Example
A manufacturing system accepts raw
materials as input and produces finished goods as output. An information system
also is a system that accepts resources (data) as input and process them into
products (information) as output.
FEEDBACK AND CONTROL
A system with feedback and control
components is sometimes called a cybernetic system, that is, a self-monitoring, self-regulating system.
·
Feedback is data
about the performance of a system. For example, data about sales performance is
feedback to a sales manager.
·
Control involves
monitoring and evaluating feedback to determine whether a system is moving
toward the achievement of its goal. The control function then makes necessary
adjustments to a system’s input and processing components to ensure that it
produces proper output. For example, a sales manager exercises control when he
or she reassigns salespersons to new sales territories after evaluating
feedback about their sales performance.
Feedback is frequently included as part of the concept
of the control function because it is such a necessary part of its operation.
Example
A familiar
example of a self-monitoring, self-regulating system is the thermostat
controlled heating system found in many homes; it automatically monitors and
regulates itself to maintain a desired temperature. Another example is the
human body, which can be regarded as cybernetic system that automatically
monitors and adjusts many of its functions, such as temperature, heartbeat, and
breathing.
OTHER SYSTEM CHARACTERISTICS
A system does not exist in a vacuum;
rather, it exists and functions in and environment containing other systems. If a system is one of the
components of a larger system, it is a subsystem, and the larger system in environment. Also, its
environment. Also, its system
boundary separates a system from its environment and other systems.
Example
Organizations such as businesses and
government agencies are good examples of the systems in society, which is their
environment. Society contains a multitude of such systems, including
individuals and their social, political, and economic institutions.
Organizations themselves consist of many subsystems, such as departments,
divisions, process teams, and other workgroups. Organizations are examples of
open systems because they interface and interact with other systems in their
environment. Finally, organizations are examples of adaptive systems, since
they can modify themselves to meet the demands of a changing environment.
COMPONENTS OF AN INFORMATION SYSTEM
An information system is a system
that accepts data resources as input and processes them into information
products as output.
An information system depends on the
resources of people (end users and IS specialists), hardware (machines and
media), software (programs and procedures), data (data and knowledge basis),
and networks (communications media and network support) to perform input,
processing, output, storage, and control activities that convert data resources
into information products.
This information system model
highlights the relationships among the components and activities of information
systems. It provides a framework that emphasizes four major concepts that can
be applied to all types of information systems:
·
People, hardware, software, data, and networks are the
five basic resources of information systems.
·
People resources include end users and IS specialists,
hardware resources consist of machines and media, software resources include
both programs and procedures, data resources can include data and knowledge
bases, and network resources include communications media and networks.
·
Data resources are transformed by information
processing activities into a variety of information products for end users.
·
Information processing consists of input, processing,
output, storage, and control activities.
INFORMATION
SYSTEM RESOURCES
(i) PEOPLE RESOURCES
People
are required for the operation of all information systems. These people
resources include end users and IS specialists.
·
End users (also
called users or clients) are people who use an information system or the
information it produces. They can be accountants, salespersons, engineers,
clerks, customers, or managers. Most of us are information system end users.
·
IS
Specialists are people who develop and operate information systems. They
include systems analysts, programmers, computer operators, and other managerial
technical, and clerical IS personnel. Briefly, systems analysts design
information systems based on the information requirements of end uses,
programmers prepare computer programs based on the specifications of systems
analysts, and computer operators operate large computer systems.
(ii) HARDWARE
RESOURCES
The concept
of Hardware resources includes all
physical devices and materials used in information processing. Specially, it
includes not only machines, such as
computers and other equipment, but also all data media, that is, all tangible objects on which data is recorded,
from sheets of paper to magnetic disks. Example of hardware in computer-based
information systems are:
·
Computer
systems, which consist of central processing units containing
microprocessors, and variety of interconnected peripheral devices. Examples are
microcomputer systems, midrange computer systems, and large mainframe computer
systems.
·
Computer
peripherals, which are devices such as a keyboard or electronic mouse for
input of data and commands, a video screen or printer for output of
information, and magnetic or optical disks for storage of data resources.
(iii) SOFTWARE
RESOURCES
The
concept of Software Resources includes
all sets of information processing instructions. This generic concept of
software includes not only the sets of operating instructions called programs, which direct and control
computer hardware, but also the sets of information processing instructions
needed by people, called procedures.
It
is important to understand that even information systems that don’t use
computers have a software resource component. This is true even for the
information systems of ancient times, or the manual and machine-supported
information systems still used in the world today. They all require software
resources in the form of information processing instructions and procedures in
order to properly capture, process, and disseminate information to their users.
The following are the
examples of software resources:
·
System
Software, such as an operating system program, which con controls and
supports the operations of a computer system.
·
Application
Software, which are programs that direct processing for a particular
use of computers by end users. Examples are a sales analysis program, a payroll
program, and a work processing program.
·
Procedures,
which are operating instructions for the people who will use an
information system. Examples are instructions for filling out a paper form or
using a software package.
(iv) DATA
RESOURCES
Data is more
than the raw material of information systems. The concept of data resources has
been broadened by managers and information systems professionals. They realize
that data constitutes a valuable organization resource. Thus, you should view
data as data resources that must be managed effectively to benefit all end
users in an organization.
Data
can take many forms, including traditional alphanumeric data, composed of
numbers and alphabetical and other characters that describe business
transactions and other events and entities. Text data, consisting of sentences
and paragraphs used in written communications; image data, such as graphic
shapes and figures; and audio data, the human voice and other sounds, are also
important forms of data.
The
data resources of information systems are typically organized into:
·
Database that hold processed and organized data.
·
Knowledge bases that hold knowledge in variety of
forms such as facts, rules, and case examples about successful business
practices.
For
example, data about sales transactions may be accumulated and stored in a sales
database for subsequent processing that yields daily, weekly, and monthly sales
analysis reports for management. Knowledge bases are used by knowledge
management systems and expert systems to share knowledge and give expert advice
on specific subjects.
DATA VERSUS INFORMATION
The word data is the plural of datum, though data
commonly represents both singular and plural forms. Data are raw facts or
observations, typically about physical phenomena or business transactions. For
example, a spacecraft launch or the sale of an automobile would generate a lot
of data describing those events. More specifically, data are objective
measurements of the attributes (the characteristics) of entities (such as
people, places, things, and events).
Example
A
spacecraft launch generates vast amounts of data. Electronic transmissions of
data (telemetry) form thousands of sensors are converted to numeric and text
data by computers. Voice and image data are also captured through video and
radio monitoring of the launch by mission controllers. Of course, buying a car
or an airline ticket also produces a lot of data. Just think of the hundreds of
facts needed to describe the characteristics of the car you want and its
financing, or the details for even the simplest airline reservation.
Peoples often use the terms data and information
interchangeably. However, it is better to view data as raw material resources
that are processed into finished information products. Then we can define information as data that have been
converted into a meaningful and useful context for specific end users. Thus,
data are usually subjected to a value-added process (we call data processing or
information processing) where (1) its form is aggregated, manipulated, and
organized; (2) its content is analyzed and view information as processed data
placed in a context for human user. So you should view information as processed
data placed in a context that gives it value for specific end users.
Example
Names, quantities, and dollar amounts recorded on
sales forms represent data about sales transactions. However, a sales manager
may not regard these as information. Only after such facts are properly
organized and manipulated can meaningful sales information be furnished,
specifying, for example, the amount of sales by product type, sales territory,
or sales persons.
NETWORK RESOURCES
Telecommunications networks like the Internet,
intranets, and extranets have become essential to the successful operations of
all types of organizations and their computer-based information systems. Telecommunications
networks consist of computers, communications processors, and other devices
interconnected by communications media and controlled by communications
software. The concept of Network
resources emphasizes that communications networks are a fundamental
resource component of all information systems. Network resources include:
·
Communication
media, Examples include twisted pair wire, coaxial cable,
fiber-optic cable, microwave systems, and communication satellite systems.
·
Network
Support, This generic category includes all of the people, hardware,
software, and data resources that directly support the operation and use of a
communications network. Examples include communications control software such
as network operating systems and Internet packages.
INFORMATION SYSTEM ACTIVITIES
You
should be able to recognize input, processing, output, storage and control
activities taking place in any information system you are studying.
(i) INPUT OF DATA RESOURCE
Data about business
transactions and other events must be captured and prepared for processing by
the input activity. Input typically takes the form of data
entry activities such as recording and editing. End uses typically
record data about transactions on some type of physical medium such as paper
form, or enter it directly into a computer system. This usually includes a
variety of editing activities to ensure that they have recorded data correctly.
Once entered, data may be transferred onto a machine-readable medium such as a
magnetic disk until needed for processing.
For example, data about
sales transactions can be recorded on source documents such as paper sales
order forms. (A source document is the original formal record of a
transaction). Alternately, salespersons can capture sales data using computer
keyboards or optical scanning devices; they are visually prompted to enter data
correctly by video displays. This provides them with a more convenient and
efficient user interface, that is,
methods of end user input and output with a computer system. Methods such as
optical scanning and displays of menus, prompts, and fill-in-the-blanks formats
make it easier for end users to enter data correctly into an information
system.
(ii) PROCESSING OF DATA INTO INFORMATION
Data is typically
subjected to processing activities such as calculating, comparing, sorting,
classifying, and summarizing. These activities organize, analyze and manipulate
data, thus converting them into information for end users. The quality of any
data stored in an information system must also be maintained by a continual
process of correcting and updating activities.
For example, data
received about a purchase can be (1) added to a running total of sales results,
(2) compared to a standard to determine eligibility for a sales discount, (3)
sorted in numerical order based on product identification numbers, (4)
classified into product categories (such as food and nonfood items), (5)
summarized to provide a sales manager with information about various product
categories, and finally, (6) used to update sales records.
(iii) OUTPUT OF INFORMATION PRODUCTS
Information in various
forms is transmitted to end-users and made available to them in the output
activity. The goal of information systems is the production of appropriate
information products for end users. Common information products messages,
reports, forms, and graphic images, which may be provided by video displays,
audio responses, paper products, and multimedia. For example, a sales manager
may view a video display to check on the performance of a salesperson, accept a
computer-produced voice message by telephone, and receive a printout of monthly
sales results.
(iv) STORAGE OF DATA RESOURCE
Storage is a basic
system component of information systems. Storage is the information system activity
in which data and information are retained in an organized manner for later
use. For example, just as written text material is organized into words,
sentences, paragraphs, and documents, stored data is commonly organized into
fields, records, files, and database. This facilitates its later use in
processing or its retrieval as output when needed by users of a system.
(v) CONTROL OF SYSTEM PERFORMANCE
An important information
system activity is the control of its performance. An information system should
produce feedback about its input, processing, output, and the system is meeting
established performance standards. Then appropriate system activities must be
adjusted so that proper information products are produced for end users.
For example, a manager may discover
that subtotals of sales amounts in a sales report do not add up to total sales.
This might mean that data entry or processing procedures need to be corrected.
Then changes would have to be made to ensure that all sales transactions would
be properly captured and processed by a sales information system.
RECOGNIZING INFORMATION SYSTEM
There
are many kinds of information systems in the real world. All of them use
hardware, software, network, and people resources to transform data resources
into information products. Some are simple manual information systems, where
people use simple tools such as pencils and paper, or even machines such as
calculators and typewriters. Others are computer based information systems that
rely on a variety of networked computer systems to accomplish their information
processing activities.
As
business end user, you should be able to recognize the fundamental components
of information systems you encounter in the real world. This means that you
should be able to identify:
·
The people, hardware, software, data, and network
resources they use.
·
The type of information products they produce.
·
The way they perform input, processing, output,
storage and control activities.
·
How they support the business operations, managerial
decision-making, or competitive advantage of a business.
This kind
of understanding will help you be a better user, developer, and manager of
information system.
THE EXPANDING ROLES OF INFORMATION
SYSTEM
You
will also see that the roles given to the information systems functions have
expand significantly over the years.
TRENDS INFORMATION SYSTEMS
Until
the 1990s, the role of information systems was simple, transaction processing,
record-keeping, accounting, and other electronic data processing (EDP)
applications. Then another role was added, as the concept of management
information system (MIS) was conceived. This new role focused on providing
managerial end users with predefined management reports that would give
managers the information they needed for decision-making purposes.
By
the 1970s, it was evident that the pre-specified information products produced
by such management information systems were not adequately meeting many of the
(DSS) was born. The new role for information systems was to provide managerial
end users with ad hoc and interactive support of their decision-making
processes.
In
the 1980s, several new roles for information systems appeared. First, the rapid
development of microcomputer processing power, application software packages,
and telecommunications networks give birth to the phenomenon of end user
computing. Now, end users can use their own computing resources to support
their job requirements instead of waiting for the indirect support of corporate
information services departments.
Second,
it became evident that most top corporate executives did not directly use
either the reports of information reporting systems or the analytical modeling
capabilities of decision support systems, so the concept of executive
information systems (EIS) was developed. These information systems attempt to
give top executives an easy way to get the critical information they want, when
they want it, tailored to the formats they prefer.
Third,
breakthrough s occurred in the development and application of artificial
intelligence (AI) techniques to business information systems. Expert systems
can serve as consultants to users by providing expert advice in limited subject
areas.
An
important new role for information systems appeared in the 1980s and continues
into the 1990s. This is the concept of a strategic role for information
systems, sometimes called strategic information systems (SIS). In this concept,
information technology becomes an integral component of business processes,
products, and services hat help a company gain a competitive advantage in the
global marketplace.
Finally,
the rapid growth of the Internet, intranets, extranets, and other
interconnected global networks in the 1990s is dramatically changing the
capabilities of information systems in business as we move into the next
century. Such enterprise and global internetworking is revolutionizing end
user, enterprise, and inter organizational computing, communications, and
collaboration that supports the business operations and management of
successful global enterprises.
TYPES OF INFORMATION SYSTEM
Conceptually,
information systems in the real world can be classified in several different
ways. For example, several types of information systems can be classified
conceptually as either operations or management information systems.
(i) OPERATIONS SUPPORT SYSTEMS
Information systems have
always been needed to process data generated by, and used in, business
operations. Such operations support systems produce a variety of information
products for internal and external use. However, they do not emphasize
producing the specific information products that can best be sued by managers.
Further processing by management information systems is usually required. The
role of a business firm’s operations support systems is to efficiently process
business transactions, control industrial processes, support enterprise
communications and collaboration, and update corporate databases.
(ii) TRANSACTION PROCESSING SYSTEMS
Operations support
systems include the major category of transaction processing systems (TPS).
Transaction processing systems record and process data resulting fro business
transactions. Typically examples are information systems that process sales,
purchases, and inventory changes. The results of such processing are sued to
update customer, inventory, and other organizational databases. These databases
then provide the data resources that can be processed and used by management
information systems, decision support systems, and executive information
systems.
Transaction processing
systems process transactions in two basic ways. In batch processing,
transactions data is accumulated over a period of time and processed
periodically. In real-time (or online) processing, data is processed
immediately after a transaction occurs. For example, point of sale (POS)
systems at retail stores may use electronic cash register terminals to capture
and transmit sales data over telecommunication links to regional computer
centers for immediate (real-time) or nightly (batch) processing.
(iii) PROCESS CONTROL SYSTEMS
Operation support
systems also make routine decisions that control operational processes.
Examples are automatic inventory reorder decisions and production control
decisions. This includes a category of information systems called process
control systems, in which decisions adjusting a physical production process are
automatically made by computers. For example, a petroleum refiner uses
electronic sensors linked to computers to continually monitor chemical
processes. The computers monitor a chemical process, capture and process data
detected by sensors, and make instant (real-time) adjustments to appropriate
refinery processes.
(iv) ENTERPRISE
(v) MANAGEMENT SUPPORT SYSTEMS
When information systems
focus on providing information and support for effective decision making by
managers, they are called management support systems.
MANAGEMENT INFORMATION SYSTEMS
Management
information systems (MIS) are the most common form of management support
systems. They provide managerial end users with information products that
support much of their day-to-day decision-making needs. Management information
systems provide a variety of reports and displays to management. The contents
of these information products are specified in advance by managers so that they
contain information that managers need. Management information systems retrieve
information about internal operations from database that have been updated by
transaction processing systems. They also obtain data about the business
environment from external source.
Information
products provided to managers include displays and reports that can be furnished
(1) on demand, (2) periodically, according to a predetermined schedule.
(i) DECISION SUPPORT SYSTEMS
Decision support systems
(DSS) are a natural progression from information reporting systems and
transaction processing systems. Decision support systems are interactive,
computer-based information systems that use decision models and specialized
database to assist the decision making process of managerial end users.
(ii) EXECUTIVE INFORMATION SYSTEMS
Executive information
systems (EIS) are management information systems tailored to the strategic
information needs of top management. Top executives get the information they
need from many sources, including letters, memos, periodicals, and reports
produced manually as well as by computer systems. Other sources of executive
information are meetings, telephone calls, and social activities. Thus, much of
a top executive’s information comes from non-computer services. Computer
generated information ahs not played a primary role in meeting many top executives’
information needs.
OTHER CLASSIFICATIONS OF
INFORMATION SYSTEMS
(i) EXPERT SYSTEMS
An expert system is a
knowledge-based information systems; that is, it uses its knowledge about a
specific area to act as an expert consultant to users. The components of an
expert system are a knowledge base and software modules that perform inferences
on the knowledge and offer answers to a user’s questions. Expert systems are
being used in many different fields, including medicine, engineering, the
physical sciences, and business. For example, expert systems now help diagnose
illnesses, search for minerals, analyze compounds, recommend repairs, and do
financial planning. Expert systems can support either operations or management
activities.
(ii) KNOWLEDGE MANAGEMENT SYSTEMS
Knowledge Management
systems (KMS), Workers create, organize, and share important business knowledge
wherever and whenever it is needed. For example, many knowledge management
systems rely on Internet and intranet Web sites, knowledge bases, and
discussion forums as key technologies for gathering, storing, and disseminating
business knowledge. In this way, knowledge management systems facilitate
organization learning and knowledge creation and dissemination within the
business enterprise.
(iii) STRATEGIC INFORMATION SYSTEMS
The strategic role of
information systems involves using information technology to develop products,
services, and capabilities that give a company strategic advantages over the
competitive forces it faces in the global marketplace. This creates strategic
information system, information systems that support or shape the competitive
position and strategies of an enterprise. So a strategic information system can
be any kind of information systems (TPS, MIS, DSS, etc.) that helps an
organization gain a competitive advantage, reduce a competitive disadvantage,
or meet other strategic enterprise objectives.
(iv) BUSINESS INFORMATION SYSTEMS
As a future managerial
end user, it is important for you to realize that information systems directly
support both operations and management activities in the business functions of
accounting, finance, human resource management, marketing, and operations
management. Such business information systems are needed by all business
functions.
For example, marketing
managers need information about sales performance and trends provided by
marketing information systems. Financial managers need information concerning
financing costs and investment returns provided by financial information
systems.
(v) INTEGRATED INFORMATION SYSTEM
It is also important to
realize that information systems in the real world are typically integrated
combinations of several types of information systems we have just mentioned.
That’s because conceptual classification of information systems are designed to
emphasize the many different roles of information systems. In practice, these
roles are integrated into composite or cross-functional information systems
that provide a variety of functions. Thus, most information systems are
designed to produce information and support decision making for various levels
of management and business functions, as well as do record keeping and
transaction processing systems.
THE SYSTEMS
APPROACH
The
systems approach to problem solving used a systems orientation to define
problems and opportunities and develop solutions. Studying a problem and formulating a solution
involve the following interrelated activities:
1.
Recognize and define a problem or opportunity using
systems thinking.
2.
Develop and evaluate alternative system solutions.
3.
Select the system solution that best meets your
requirements.
4.
Design the selected system solution.
5.
Implement and evaluate the success of the designed
system.
DEFINING
PROBLEMS AND OPPORTUNITIES
Problems
and opportunities are identified in the first step of the systems approach. A
problem can be defined as a basic condition that is causing undesirable
results. An opportunity is a basic condition that presents the potential for
desirable results. Symptoms must be separated from problems. Symptoms are
merely signals of an underlying cause or problem.
Example
Symptom:
Sales of a company’s products are declining. Problem: Sales persons are losing
orders because they cannot get current information on product prices and availability.
Opportunity : We could increase sales
significantly if sales persons could receive instant responses to requests for
price quotations and product availability.
SYSTEMS
THINKING
Systems
thinking is to try to find systems, subsystems, and components of systems in
any situation your are studying. This viewpoint ensures that important factors
and their interrelationships are considered. This is also known as using a
systems context, or having a systemic view of a situation. I example, the
business organization or business process in which a problem or opportunity
arises could be viewed as a system of input, processing, output, feedback, and
control components. Then to understand a problem and save it, you would
determine if these basic system functions are being properly performed.
Example
The
sales function of a business can be viewed as a system. You could then ask: Is
poor sales performance (output) caused by inadequate selling effort (input),
out-of-date sales procedures (processing), incorrect sales information
(feedback), or inadequate sales management (control)? Figure illustrates this concept.
 |
|||||||||||
 |
|||||||||||
|
|
|
|||||||||
DEVELOPING
ALTERNATIVE SOLUTIONS
There
are usually several different ways to solve any problem or pursue any
opportunity. Jumping immediately from problem definition to a single solution
is not a good idea. It limits your options and robs you of the chance to
consider the advantages and disadvantages of several alternatives. You also
lose the chance to combine the best points of several alternative solutions.
Where
do alternative solutions come from/ experience is good source. The solutions
that have worked, or at least been considered in the past, should be considered
again. Another good source of solutions is the advice of others, including the
recommendations of consultants and the suggestions of expert systems. You
should also use your intuition and ingenuity to come up with a number of
creative solutions. These could include what you think is an ideal solution.
The, more realistic alternatives that recognize the limited financial,
personnel, and other resources of most organizations could be developed. Also,
decision support software packages can be used to develop and manipulate
financial, marketing, and other business operations. This simulation process
can help you generate a variety of alternative solutions. Finally, don’t forget
that “doing nothing” about a problem or opportunity is a legitimate solution,
with its own advantages and disadvantages.
EVALUATING
ALTERNATIVE SOLUTIONS
Once
alternative solutions have been developed, they must be evaluated so that the
best solution can be identified. The goal of evaluation is to determine how
well each alternative solution meets your business and personal requirements.
These requirements are key characteristics and capabilities that you feed are
necessary for your personal or business success.
Example
If
you were the sales manager of a company, you might develop very specific
requirements for solving the sales-related information problems of your
salespeople. You would probably insist that any computer-based solution for
your sales force be very reliable and easy to use. You might also require that
any proposed solution have low start-up costs, or have minimal operating costs
compared to present sales processing methods.
Then
you would develop evaluation criteria and determine how well each alternative
solution meets these criteria. The criteria you develop will reflect how you
previously defined business and personal requirements. For example, you will
probably develop criteria for such factors as start-up costs, operating costs,
ease of use, and reliability.
Criteria
may be ranked or weighted, based on their importance in meeting your
requirements.
SELECTING
THE BEST SOLUTION
Once
all alternative solutions have been evaluated, you can being the process of
selecting the best solution. Alternative solutions can be compared to each
other because they have been evaluated using the same criteria.
Example
Alternatives
with a low accuracy evaluation (an accuracy score less than 10), or a low
overall evaluation (an overall score less than 70) should be rejected.
Therefore,
alternative B for sales data entry is rejected, and alternative A, the use of
laptop computers by sales reps, is selected.
DESIGNING
AND IMPLEMENTING A SOLUTION
Once
a solution has been selected, it must be designed and implemented. You may have
to depend on other business end users technical staff to help you develop design specifications and
an implementation plan. Typically, design specifications might describe the
detailed characteristics and capabilities of the people, hardware, software,
and data resources and information system activities needed by a new system. An
implementation plan specifies the resources, activities, and timing needed for
proper implementation. For example, the following items might be included in
the design specifications and implementation plan for a computer-based sales
support system:
·
Types and sources of computer hardware, and software
to be acquired for the sales reps.
·
Operating procedures for the new sales support system.
·
Training of sales reps and other personnel.
·
Conversion procedures and timetable for final
implementation.
POST
IMPLEMENTATION REVIEW
The final step of the systems
approach recognizes that an implemented solution can fail to solve the problem
for which it was developed. The real world has a way of confounding even the
most well-designed solutions. Therefore, the results of implementing a solution
should be monitored and evaluated. This is called a postimple-implemented. The
focus of this step is to determine if the implemented solution has indeed
helped the firm and selected subsystems meet their system objectives. If not,
the systems approach assumes you will cycle back to a previous step and make
another attempt to find a workable solution.
THE SYSTEMS
DEVELOPMENT CYCLE.
When the systems approach to problem
solving is applied to the development of information system solutions to
business problems, it is called information systems development or application
development. Most computer-based information systems are conceived, designed,
and implemented using some form of systematic development process. In this
process, end users and information specialists design information systems based
on an analysis of the information requirements of an organization. Thus, a
major part of this process is known as systems analysis and design.
Using the systems approach to
develop information system solutions involves a multistep process called the
information systems development cycle, also know as the systems development
life cycle (SDI,C).
 |
||||||
|
||||||
|
||||||
|
||||||
|
||||||
 |
||||||
 |
||||||
|
||||||
STARTING
THE SYSTEMS DEVELOPMENT PROCESS.
Do we have business problem (or opportunity)?
What is causing the problem? Would a new or improved information system help
solve the problem? What would be a feasible information system solution to our
problem? These are the questions that have to be answered in the system
investigation stage-the first step in the systems development process. This
stage may involve consideration of proposals generated by an information
systems planning process.
FEASIBILITY
STUDIES.
The process of developing a major
information system can be costly, the systems investigation stage frequently
requires a preliminary study called a feasibility study. A feasibility study is
a preliminary study which investigates the information needs of prospective
users and determines the resource requirements, costs, benefits, and
feasibility of proposed project. You would use the methods of gathering
information to collect data for a feasibility study. Then you might formalize
the findings of this study in written report that includes preliminary
specifications and a development plan for the proposed system. If management
approves the recommendations of the feasibility study, the development process
can continue.
The goal of feasibility studies is
to evaluate alternative systems and to propose the most feasible and desirable
systems for development. The feasibility of a proposed system can be evaluated
in terms of four major categories.
The focus of organizational
feasibility is on how well a proposed information system supports the
objectives of the organization and its strategic plan for information systems.
For example, projects that do not directly contribute to meeting an
organization’s strategic objectives are typically not funded. Economic
feasibility is concerned with whether expected cost savings, increased revenue,
increased profits, reductions in required investment, and other types of
benefits will exceed the costs of developing and operating a proposed system.
For example, if a project can’t cover its development costs, it won’t be
approved, unless mandated by government regulations or other considerations.
Technical feasibility can be
demonstrated if reliable hardware and software capable of meeting the needs of
a proposed system can be acquired or development by the business in the
required time. Finally, operational feasibility is the willingness and ability
of the management, employees, customers, suppliers, and others to operate, use,
and support a proposed system. For example, if the software for a new system is
too difficult to use, employees may make too many errors and avoid using it.
Thus , it would fail to show operational feasibility.
Cost/Benefit Analysis. Feasibility
studies typically involve cost/benefit analysis. If costs and benefits can be
quantified, they are called tangible costs are the costs of hardware and
software, employee salaries, and other quantifiable costs needed to develop and
implement an IS solution. Intangible costs are difficult to quantity; they
included the loss of customer goodwill or employee morale caused by errors and
disruptions arising from the installation of a new system.
Tangible. Benefits are favorable results, such as the
decrease in payroll costs caused by a reduction in personnel or a decrease in
inventory carrying costs caused by a reduction in inventory. Intangible
benefits are harder to estimate. Such benefits as better customer service
or faster and more accurate informations for management fall into this
category.
SYSTEMS
ANALYSIS.
It is an in-depth study of end user
information needs that produces functional requirements that are used as the
basis for the design of a new information system. Systems analysis
traditionally involves a detailed study of:
q The
information needs of the organization and end users like yourself.
q The
activities, resources, and products of any present information systems.
q The
information system capabilities required to meet your information needs, and
those of other end users.
ORGANIZATIONAL
ANALYSIS.
An organization analysis is an
important first step in systems analysis. How can anyone improve an information
system if they know very little about the organizational environment in which
that system is located? They can’t. That’s why the members of a development
team have to know something about the organization, its management structure,
its people, its business activities, the environmental systems I must deal
with, and its current information system. Someone on the team must know this
information in more detail for the specific business units or end user
workgroups that will be affected by the new or improved information system
being proposed. For example, a new inventory control system for a chain of
department stores cannot be designed unless someone on a development team knows
a lost about the company and the types of business activities that affect its
inventory.
ANALYSIS OF
THE PRESENT SYSTEM.
Before you design a new system, it
is important to study the system that will be improved or replaced (if there is
one). You need to analyze how this system uses hardware, software, network, and
people resources to convert data resources, such as transactions data, into
information products, such as reports and displays. Then you should document
how the information system activities of input, processing, output, storage,
and control are accomplished.
For example, you might evaluate the
format, timing, volume, and quality of input and output activities. Such user
interface activities are vital to effective interaction between end users and
computers. Then, in the systems design stage, you can specify what the
resources, products, and activities should be to support the user interface in
the system you are designing.
FUNCTIONAL REQUIREMENTS ANALYSIS.
This step of systems analysis is one
of the most difficult. Your may need to work as a team with systems analysis
and other end users to determine your specific business information needs. For
example, you need to determine what type of information your work requires;
what its format, volume, and frequency should be; and what response times are
necessary. Second, you must try to determine the information processing
capabilities required for each system activity (input, processing, output,
storage, control) to meet these information needs. Your main goal is to
identity what should be done, not bow to do it.
Functional requirements are end user
information requirements that are not tied to the hardware, software, network,
data, and people resources that end users presently use or might use in the new
system.
SYSTEMS
DESIGN.
Systems analysis describes what a
system should do to meet the information needs of users. Systems design
specifies how the system will accomplish this objective. Systems design
consists of design activities that produce system specifications satisfying the
functional requirements developed in the systems analysis stage.
Systems design consists of three
activities: user interface, data, and process design.
User Interface Design. The user interface design activity
focuses on supporting the interactions between end users and their
computer-based applications. Designers concentrate on the design of attractive
and efficient forms of user input and output, such as easy-to-use Internet or
intranet Web pages. Or they may design methods of converting human-readable
documents to machine-readable input, such as optical scanning of business
forms.
For example, here are some design
tips to keep in mind when you are designing a Web site for a business
application:
q Keep it
simple. Avoid complex jargon, overwrought explanations, and confusing tangents.
Always keep the customer’s point-of-vie in focus. Ask yourself, “What have they
come here to do? “Then design a site that matches the answer.
q Keep is
clean. Image isn’t everything on the Net, but is certainly counts for a lot. A
functional Web site should avoid gratuitous displays of techno-tricks that
cluter up the site.
q Organize
logically. Go with the three-click rule: It users can’t get to the core of the
information they’re looking for in three clicks, they’ll abandon the search.
Data Design. The data design activity focuses on the
design of the structure of databases and files to be used by proposed
information system.
The product
of data design is detailed descriptions of:-
o The
attributes or characteristics of the entities (objects, people, places, events)
about which the proposed information system needs to maintain information.
o The
relations these entities have to each other.
o The
specific data elements (databases, files, records etc.) that need to be
maintained for each entity tracked by the information system.
o The
integrity rules that govern how each data element is specified and used in the
information system.
Process Design: The process design activity focuses on the
design of software resources, that is the programs and procedures needed by the
proposed information systems. Designers concentrate on developing detailed
specifications for the software that will have to be purchased or developed by
custom programming to meet user interface and data design specification, and the
functional requirements developed in the analysis stage.
Because of the widespread use of
client/server systems, software process design is frequently expressed as a
“there-tier” architecture of processing services:
o User
Services: Front-end
client software that communicates with users through a graphical user
interface.
o Application
Services: Software modules
that enforce business rules, process information, and manage transactions.
Application services may reside on the client and server.
o Data
Services: Data is made
available to the application services software for processing. This is
typically accomplished through a database management system.
SYSTEM
SPECIFICATIONS.
System Specifications: Formalize the design of an application’s
user interface methods and products, database structures, and processing and
control procedures. Therefore, systems designers will frequently develop
hardware, software, network, data and personnel specifications for a proposed
system. Systems analysts work with you so they can use your knowledge of your
own work activities and their knowledge of computer bases systems to specify
the design of a new of improved information system.
The final system design must specify
what types of hardware resources (machines and media), software resources
(programs and procedure), network
resources ( communications media and networks), and [people resources (end
users and information systems staff) will be needed. It must specify how such
resources will convert data resources (stores in files and databases they
design) into information products (displays, responses, reports, and
documents). These specification are the final product of the systems design
stage.
|
o User
Interface Specifications
Use handheld optical scanning wands to automatically capture
product data on bar-coded tags. Use data entry screens with key data
highlighted for better readability.
|
|
o Database
Specifications
Develop databases that use a relational structure to
organize access to all necessary customers and merchandise data.
|
|
o Software
Specifications
Develop or acquire a sales processing program that can
accept entry of optically scanned bar codes, retried necessary [product data,
and compute sales amounts In less than one second. Acquire a rational
database management package to manage stores databases.
|
|
o Hardware
and Network Specifications
Install POS terminals at each checkout station connected to
a system of network station connected to a system of networked micro
computers in each store that are also connected to the corporate headquarters
network.
|
|
o Personnel
Specifications:
All hardware and software must be operatable by regular
store personnel. IS personnel should be available for hardware and software
maintenance as needed.
|
PROTOTYPING.
Prototyping is the repaid development
and testing of working models, or prototypes, of new applications in an
interactive, iterative process can be used by both systems analysts and end
users. Prototyping makes the development process faster and easier for systems
analysts, especially for projects where end user requirements are hard to
define. Thus, prototyping is sometimes called rapid application design (RAD)
Prototyping
has also opened up the application development process to end users because it
simplifies and accelerates systems design. These developments are changing the
roles of end users and information systems specifications in systems
development.
THE
PROTOTYPING PROCESS.
Prototyping
can be used for both large and small applications. Typically, large systems
still require using the traditional systems development approach, but parts of
such systems can frequently by prototyped. A [prototype of a business
application needed by an end user is developed quickly using a variety of
application development packages. The prototype system is then repeatedly
refined until it is acceptable to an end user
o
|
 |
o
|
 |
o
|
|
 |
o
Implementation/Maintenance: The acceptable information
system can be modified easily since most system documentations stores on disk.
Implementation/Maintenance: The acceptable information
system can be modified easily since most system documentations stores on disk.
Prototyping
is an iterative, interface process that combines steps of the traditional
systems development cycle. End users with sufficient experience with
application development packages can be prototyping themselves. Alternatively,
an end user can work with a systems analyst to develop a prototype system in a
series of interactive sessions. For example, they could be develop, test and
refine prototypes of management reports or data entry screens.
The
Prototype is usually modified several times until the end user finds it
acceptable. Any program modules that are not generated by the application
development software can then be codes by programmers using conventional
programming languages. The final version of the application system is then
turned over to the end user for operational use.
|
* Team. A few end users and IS developers form a team to develop a
business application.
|
|
* Schematic. The initial prototype schematic design is developed
|
|
* Prototype. The schematic is converted into a simple
point-and-click prototype using prototyping tools.
|
|
* Presentation. A few screens and routine/linkages are presented to
users.
|
|
* Feedback. After the team gets feedback from users, the prototype
is reiterated.
|
|
* Reiteration. Further presentations and reiterations are made.
|
|
* Consultation. Consultations are held with central IT
developers/consultants to identify potential improvements and conformance to
existing standards of the organization.
|
|
* Completion. The prototype is converted into a finished
application.
|
|
* Acceptance. Users review and sign of on their acceptance of the
new system.
|
|
* Installation. The new application software is installed on
network servers.
|
Once a new information
system has been designed, it must be implemented. Figure 3.27 illustrates that
the systems implementation stage involves hardware and software acquisition,
software development, testing of programme and procedures, development of
documentation, and a variety of installation activities. It also involves the
education and training of end users and specialists who will operate a new
system.
|
|||
 |
|||
Finally,
implementation involves a
conversion process from
the use of a present system to the operation of a new or
improved application. Conversion methods can soften the impact of introducing
new technology into an organization. Thus, conversion may involve operating
both new and old systems in parallel for a trial period, or operation of a
pilot system on a trial basis at one location. Phasing in the new system in one
application or location at a time is another popular
conversion method. However, a plunge or immediate cutover to a new information
system is also a widely used conversion method.
|
Maintenance of
information
Systems
|
Systems maintenance is the final stage
of the system development cycle. It involves the monitoring, evaluation, and
modifying of a system to make desirable or necessary improvements. This may
include a post-implementation
review process to ensure that the newly implemented system is meeting
the functional business requirements that were established for it when it was
designed. Errors in the development of a system are corrected by the
maintenance activity. Systems maintenance also includes modifying a system
due to internal changes in a business or external changes in the business
environment. For example, development of new products or services, or change
in the tax laws might require making changes to a company’s
marketing and accounting systems.
|
|
Computer-Aided
Systems Engineering
|
Computer-aided systems engineering (CASE), which also
stands for computer-aided software engineering, involves using software
packages, called CASE tools, to perform many of the activities
o the systems development life cycle. For example, software packages are
available to help do business planning, project management, user interface
prototyping, database design, and software development. Thus, CASE tools make
a computer-aided systems development process possible.
|
The components of
CASE. This is an example of the variety of software tools and repositories in
an integrated CASE products.
|
||||||||||||||||||||||||||||
 |
||||||||||||||||||||||||||||
 |
 |
|||||||||||||||||||||||||||
 |
|
 |
||||||||||||||||||||||||||
 |
||||||||||||||||||||||||||||
 |
||||||||||||||||||||||||||||
 |
||||||||||||||||||||||||||||
 |
||||||||||||||||||||||||||||
|
|
|
||||||||||||||||||||||||||
 |
||||||||||||||||||||||||||||
|
||||||||||||||||||||||||||||
|
Using
CASE Tools
|
Figure
3.9 emphasizes that CASE packages provide many computer-based tools for both
the front end of the systems development life cycle. (planning, analysis, and
design) and the back end o systems development (implementation and
maintenance). Note that server and workstation repositories help integrate
the use of tools at both ends of the development cycle. The system repository
is a computerized database for all of the details of a system generated with
other systems development tools. The repository helps to ensure consistency
and compatibility in the design of the data elements, processes, user
interfaces, and other aspects of the system being developed.
Integrated CASE tools (called-I-CASE)
are now available that can assist all of the stages of systems development.
Some of these CASE tools support joint application design (JAD)
, where a group of systems analysts, programmers,
and end users can jointly and interactively design new applications. Finally,
if the development of new system can be called forward engineering, some CASe
tools support backward engineering. That is, they allow systems analysts to
inspect the logic of a programme code for old applications, and convert it
automatically into more efficient programs that significantly improve system
effectiveness.
|
|
End
|
|
TRENDS
IN COMPUTER SYSTEMS.
Today’s computer systems
come in a variety of sizes, shapes, and computing capabilities.
Rapid hardware and software developments and changing end user needs continue
to drive the emergence of new models of computers, from the smallest hand-held
personal digital assistant for end
users, to the largest multiple-CPU mainframe for the enterprise.
Categories such as
mainframes, midrange computers, and microcomputers are still used to help us express the
relative processing power and number of end users that can be supported by
different types of computers.
In addition, experts
continue to predict the merging or disappearance of
several computer categories. They feel, for example, that many midrange and
mainframe systems have been made obsolete by the power and versatility of client/server
networks of
end user microcomputers and servers.
COMPUTER GENERATIONS.
It is important to
realize that major changes and trends in computer systems have occurred during
the major stages-or generations-of computing, and will
continue into the future. The first generation of computers developed in the
early 1950s, the second generation blossomed during the late 1960s, the third
generation took computing into the 1970s, and the fourth generation has been
the computer technology of the 1980s and 1990s. A fifth generation of computers
that accelerates the trends of the previous generations is expected to evolve
as we enter the 21st century. Notice that
computers continue to become smaller, faster, more reliable, less costly to
purchase and maintain, and more interconnected
within computer networks.
First-generation
computing involved massive
computers using hundreds or thousands of
vacuum tubes for their processing and memory circuitry. These large computers
generated enormous amounts of heat; their vacuum tubes had to be replaced
frequently. Thus, they had large electrical power, air conditioning, and
maintenance requirements. First-generation computers had main memories of only
a few thousand characters and millisecond
processing speeds. They used magnetic drums or tape for secondary storage and
punched cards or paper tape as input and output media.
Second-generation
computing used transistors and other
solid-state, semiconductor devices that were wired to
circuit boards in the computers. Transistorized circuits were much smaller and
much more reliable, generated little heat, were less expensive, and required
less power than vacuum tubes. Tiny magnetic cores were used for the computer’s
memory, or internal storage. Many second-generation computers had main memory
capacities of less than 100 kilobytes and microsecond processing, speeds.
Removable magnetic disk packs were introduced, and magnetic
tape merged as the major input, output, and secondary storage medium for large
computer installations.
Third-generation
computing saw the development of computers that used
integrated circuits, in which thousands of transistors and other
circuit elements are etched on tiny chips of silicon. Main
memory capacities increased to
several megabytes and processing speeds jumped
to millions of instructions per second (MIPS) as telecommunications
capabilities became common. This made it possible for operating system programs
to come into widespread use that automated and supervised the activities of
many types of peripheral devices and processing by mainframe
computers of several programs at the same time,
frequently involving networks of users at remote terminals. Integrated circuit
technology also made possible the development and widespread use of small computers called
minicomputers in the third computer generation.
Fourth-generation
computing relies on the use of LSI (large-scale integration) and VLSI (very-large-scale
integration) technologies that cram hundreds of thousands or
millions of transistors and other circuit elements on each chip. This enabled
the development of microprocessors, in which all of the
circuits of a CP are contained on a single chip with processing speeds of
millions of instructions per second. Main memory capacities
ranging from a few megabytes to several gigabytes can also be achieved by
memory chips that replaced magnetic core
memories. Microcomputers, which use microprocessor CPUs and a variety of
peripheral devices and easy-to-use software packages to form small personal computer (PC),
systems or client/server networks of linked PCs and servers, are a hallmark of
the fourth generation of
computing, which accelerated the downsizing of
computing systems.
Whether
we are moving into a fifth generation of computing is a subject of
debated since the concept of generations may no longer fit the continual, rapid
changes occurring in computer hardware, software, data, and networking
technologies. But in any case, we can be sure that progress in computing will continue
to accelerate, and that the development of Internet-based
technologies and
applications will be one of the major forces driving computing into the 21st
century.
MICROCOMPUTER SYSTEMS.
Microcomputers
are the most important category of computer systems for end users. Though
usually called a personal computer, or PC, a microcomputer is much more than a
small computer for use by an individual. The computing power of microcomputers
now exceeds that of the mainframes of previous computer generations at a
fraction of their cost. Thus, they have become powerful networked professional
work stations for end users in business.
Microcomputers
come in a variety of sizes and shapes for a variety of purposes. For example,
PCs are available as handhled,
notebook, laptop, portable, desktop,
and floor-standing models. Or, based on their use, they include home, personal,
professional, workstation, and multi-user systems.
Most microcomputers are desktops designed to fit on an office desk, or
notebooks for those who want a small, portable PC for their work activities.
Some microcomputers are
powerful workstation computers (technical work-stations) that support applications
with heavy mathematical computing and graphics display demands such as
computer-aided design (CAD) in engineering, or investment and portfolio
analysis in the securities industry. Other microcomputers are used as network
servers. They are usually more powerful microcomputers that
coordinate telecommunications and resource sharing in small
local area networks (LANs), and Internet and intranet Web sites. Another
important microcomputer category includes handheld microcomputer devices
known as personal digital assistants (PDAs),
designed for convenient mobile communications and
computing. PDAs use touch-screens, pen-based handwriting recognition of
keyboards to help mobile workers send and receive E-mail and exchange
information such as appointments, to do lists, and scales contacts with their
desktop PCs or Web servers.
MULTIMEDIA SYSTEMS.
Multimedia PCs
are designed to present you with information in a variety of media, including
text and graphics displays, voice and other
digitized audio, photographs, animation, and video clips. Mention multimedia,
and many people think of computer video games, multimedia encyclopedias, educational videos,
and multimedia home pages on the World Wide Web.
However, multimedia systems are widely used in business for training employees,
educating customers, making sales presentations, and adding impact to other
business presentations.
The basic hardware and
software requirements of a multimedia computer system depend on whether you
wish to create as well as enjoy multimedia presentations. Owners of low-cost
multimedia PCs marketed for home used do not need
authoring software or high-powered
hardware capacities in order to enjoy
multimedia games and other entertainment and educational multimedia
products. These computers come equipped with a CD-ROM drive, stereo speakers,
additional memory, a high-performance processor, and other multimedia
processing capabilities.
People who want to
create their own multimedia production may have to spend several thousand
dollars to put together a high-performance multimedia authoring system. This
includes a high-resolution color graphics monitor, sound and video capture
boards, a high-performance microprocessor with multimedia capabilities,
additional megabytes of memory, and several gigabytes of hard disk capacity.
Sound cards and video capture boards are circuit boards that contain digital
signal processors (DSPs) and additional megabytes
of memory for digital processing of sound and video. A digital camera, digital
video camcorder, optical scanner, and software such as authoring tools and
programs for image editing and graphics creation can add several thousand
dollars to the star-up costs of a multimedia authoring system.
MIDRANGE COMPUTER SYSTEM
Midrange Computers,
including minicomputers and high-end network servers, are multi-user systems
that can manage network of PCs and terminals. Though not as powerful as
mainframe computers, they are less costly to buy, operate, and maintain than
mainframe systems, and thus meet the computing needs of many organizations.
Midrange computers first
became popular as minicomputers for scientific research, instrumentation
systems, and industrial process monitoring and control. Minicomputers could
easily handle such uses because these applications are narrow in scope and do
not demand the processing versatility of mainframe systems. Thus, midrange
computers serve as industrial process-control and manufacturing plant
computers, and they still play a major role in computer-aided manufacturing (CAM ). They can also take the form of powerful technical
workstations for computer-aided design (CAD) and other computation and
graphics-intensive applications. Midrange computers are also used as front-end computers to assist mainframe computers in telecommunication
processing and network management.
Midrange computers have
become popular as powerful network servers to help manage large Internet
Web sites, corporate intranets and extranets, and client/server networks.
Electronic commerce and other business uses of the Internet are popular
high-end server applications, as are integrated enterprise wide manufacturing,
distribution and financial applications. Other applications, like data
warehouse management, data mining, and online analytical processing.
MAINFRAME
COMPUTER SYSTEMS
Mainframe computes are
large, fast, and powerful computer systems. For example, mainframes can process
hundreds of million instructions per second (MIPS). Mainframes also have large
primary storage capacities. Their main memory capacity can range from hundreds
of megabytes to many gigabytes of primary storage. And mainframes have slimmed
down drastically in the last few years, dramatically reducing their
air-conditioning needs, electrical power consumption, and floor space
requirements, and thus their acquisition and operating costs. Most of these
improvements are the result of a move from water-cooled mainframes to a new
CMOS air-cooled technology for mainframe systems.
Thus, mainframe
computers continue to handle the information processing needs of major
corporations and government agencies with many employees and customers or with
complex computational problems. For example, major international banks,
airlines, oil companies, and other large corporations process millions of sales
transactions and customer inquiries each day with the help of large mainframe
systems. Mainframes are still used for computation-intensive applications such
as analyzing seismic data from oil field explorations or simulating flight
conditions in designing aircraft. Mainframes are also widely used as super server for the large client/server network and high-volume
Internet Web sites of large companies.
SUPERCOMPUTER
SYSTEMS
The term supercomputer
describes a category of extremely powerful computer systems specifically
designed for scientific ,engineering, and business applications requiring
extremely high speeds for massive numeric computations. The market for
supercomputers includes government research agencies, large universities, and
major corporations. They use supercomputers for applications such as global
weather forecasting, military defense systems, computational cosmology and
astronomy, microprocessor research and design, large-scale data mining and so
on.
Supercomputers
use parallel processing architectures of interconnected microprocessors (which
can execute many instructions at the same time in parallel). They can perform
arithmetic calculations at speeds of billions of floating-point operations per
second (gigaflops). Teraflop (1 trillion floating-point operations per second)
supercomputers, which use advanced massively parallel processing (MPP) designs
of thousands of interconnected microprocessors, are becoming available.
Purchase prices for large supercomputers are in the $5 million to $50 million range.
However,
the use of symmetric multiprocessing (SMP) and distributed shared memory (DSM)
designs of smaller numbers of interconnected microprocessors has spawned a
breed of minisuper computers with prices that start in the hundreds of
thousands of dollars.
COMPUTER
SYSTEM CONCEPTS AND COMPONENTS.
The
Computer System Concept.
A
computer is more than a high-powered collection of electronic devices
performing a variety of information processing chores. A computer is a system,
an interrelated combination of components that performs the basic system
functions of input, processing, output, storage, and control, thus providing
end users with a powerful information processing tool. Understanding the
computer as a computer system is vital to the effective use and management of
computers.
A computer is system of
hardware devices organized according to the following system functions.
·
Input. The input devices of a computer
system include keyboards, touch screens, pens, electronic mice, optical
scanners, and so on.
·
Processing. The central processing unit( CPU)
is the main processing component of a computer system. (In microcomputers, it
is the main microprocessor.) In particular, the electronic circuits of the
arithmetic-logic unit one of the CPU’s major components, perform the arithmetic
and logic functions required in computer processing.
·
Output. The output devices of a computer
system include video display units, printers, audio response units , and so on,
They convert electronic information produced by the computer system into human
intelligible form for presentation to end users.
·
Storage. The storage function of a computer
system takes place in the storage circuits of the computer’s primary storage
unit, or memory, and in secondary storage devices such as magnetic disk and
tape units. These devices store data and program instructions needed for
processing.
·
Control. The control unit of the CPU is the
control component of a computer system. Its circuits interpret computer program
instructions and transmit directions to the other components of the computer
system.
The Central
Processing Unit.
The central processing
unit is the most important hardware component of a computer system. It is also
known as the CPU, the central processor or instruction processor, and the main
microprocessor in a microcomputer. Conceptually, the circuitry of a CPU can be
subdivided into two major subunits the arithmetic-logic unit and the control
unit. The CPU also includes circuitry for devices such as registers and cache
memory for high –speed, temporary storage of instruction operations, input/output, and
telecommunications support.
The control unit obtains
instructions from software segments stored in the primary storage unit and
interprets them. Then it transmits electronic signals to the other components
of the computer system to perform required operations. The arithmetic-logic
unit performs required arithmetic and comparison operations .A computer can
make logical changes from one set of program instructions to another (e.g,
overtime pay versus regular pay calculations) based on the results of
comparisons made in the ALU during processing.
Main Memory
and Primary Storage Unit.
A computer’s primary
storage unit is commonly called main memory, and holds data and program instructions
between processing steps and supplies them to the control unit and
arithmetic-logic unit during processing. Most of a computer’s memory consists
of microelectronic semiconductor memory chips known as RAM (random access
memory ). The contents of these memory chips can be instantly changed to store
new data. Other, more permanent memory chips called ROM (read only memory) may
also be used.
Secondary storage
devices like magnetic disks and optical disks are used to store data and
programs and thus greatly enlarge the storage capacities of computer system.
Also, since memory circuits typically lose their contents when electric power
is turned off, most secondary storage media provide a more permanent type of
storage. However the contents of hard disk drives floppy disks, CD-ROM disks,
and other secondary storage media cannot be processed without first being
brought into memory. Thus secondary storage devices play a supporting role to
the primary storage of a computer system.
Multiple
Processors.
Many current computers,
from microcomputers to large mainframes, use multiple processors for their
processing functions. Instead of having one CPU with a single control unit and
arithmetic-logic unit, the CPUs of these computers contain several type of
processing units. Let’s briefly look at the major types of such multiprocessor
designs.
A support processor
design relies on specialized microprocessors to help the main CPU perform a
variety of functions. These microprocessors may used for input/output, memory
management, arithmetic computations, multimedia processing, and
telecommunications, thus freeing the main processor to do the primary job of
executing program instructions For example, many microcomputers rely on support
microprocessors such as arithmetic co-processing load on their main
microprocessors. A large computer may use support microprocessors called
channels to control the movement of data between the CPU and input/output
devices. Advanced microprocessor designs integrate the functions of several support
processors on a single main microprocessor.
A coupled processor
design uses multiple CPUs or main microprocessors to do multiprocessing, that
is, executing more than one instruction at the same time. Some configurations
provide a fault-tolerant capability in which multiple CPUs provide a built-in
backup to each other should one of them fail.
A parallel processor
design uses a group of instruction processors to execute several program
instructions at the same time. Some times, hundreds or thousands of processors
are organized in clusters or networks in massively parallel processing (MPP)
computers. Other parallel processor designs are based on simple models of the
human brain called neural networks. All of these systems can execute many
instructions at a time in parallel. This is a major departure from the
traditional design of current computers, called the Von Neuman design, which
executes instructions serially (one at a time). Though difficult to program,
many experts consider parallel processor systems the key to providing advanced
capabilities to future generations of computers.
RISC Processors. Many
advanced technical workstations and other computers rely on a processor design
called RISC (reduced instruction set computer). This contrasts with most
current computers that use CISC (complex instruction set computer) processors.
RISC processor designs optimize a CPU’s processing speed by using a smaller
instruction set. That is, they use a smaller number of the basic machine
instruction that a processor is capable of executing. By keeping the
instruction set simpler than CISC processors and using more complex software, a
RISC processor can reduce the time needed to execute program instructions.
Computer
Processing Speeds.
Computer operating
speeds that were formerly measured in milliseconds (thousands of a second) and microseconds
(millionths of a second) are now in the nanosecond
(billionth of a second) range, with picosecond (trillionth of a second)
speed being attained by some computers. Such speeds seem almost
incomprehensible. For example, an average person taking one step each
nanosecond would circle the earth above 20 times in one second. Many
microcomputers and midrange computers, and most mainframe computers, operate in
the nanosecond range, and can thus process program instructions at million
instructions per second (MIPS) speeds. Another measure of processing speed is
megahertz (MHs), or millions of cycles per second. It is commonly called the
clock speed of a microprocessor, sine it is used to rate microprocessors by the
speed of their timing circuits or internal clock.
However, megahertz,
ratings can be misleading indicators of the effective processing speed of
microprocessors as measured in MIPS and other measures. That’s because processing
speed depends on a variety of factors besides a microprocessor’s clock speed.
Important examples include the size of circuitry paths, or busses, that
interconnect microprocessor components, the capacity of instruction processing
registers, the use of high-speed memory caches, and the use of specialized
microprocessors such as a math co-processor to do arithmetic calculations
faster. For example, Intel’s Pentium microprocessor runs at 66 to 200 MHz and
is rated at over 100 MIPS, which the Pentium Pro microprocessor has a top
processing rating of over 200 MIPS at similar megahertz speeds.
INPUT
TECHNOLOGY TRENDS:
You can now enter data
and commands directly and easily into a computer system through pointing
devices like electronic mice and touch pads, and technologies like political
scanning, handwriting conviction, and voice recognition. These developments
have made it unnecessary to always record data on paper source documents (such
as sales order forms, for example) and then keyboard the data into a computer
in an additional data entry step. Further improvements in voice recognition and
other technologies should enable an even more natural user interface in the
future.
POINTING
DEVICES:
Keyboards are still the
most widely used devices for entering data and text into computer systems.
However, pointing devices are a better alternative for issuing commands, making
choices, and responding to prompts displays on your video screen. They work
with you operating systems graphical user interface (GUI), which presents you
with icons, menus, windows, buttons, bars, and so on, for your selection. For
example, pointing devices such as electronic mice and touch pads allow you to
easily choose from menu selections and icon displays using point-and-click or
point-and-drag methods. See Figure 4.24.
The electronic mouse is
the most popular pointing device used to move the cursor on the screen, as well
as to issue commands and make icon and menu selections. By moving the mouse on
a desktop or pad, you can move the cursor onto and icon displayed on the
screen. Pressing buttons on the mouse activates various activities
representation by the icon selected.
The trackball, pointing
stick, and touch pad are other pointing devices most often used in place of the
mouse. A trackball is a stationary device related to the mouse. You turn a
roller ball with only its top exposed outside its case to move the cursor on
the screen. A pointing stick (also called a track point ) is a small button
like device, sometimes likened to the eraser head of pencil. It is usually
centered one row above the space bar of a keyboard. The cursor moves in the
direction of the pressure you place on the stick. The touch pad is a small
rectangular touch-sensitive surface usually placed below the keyboard. The cursor
moves in the direction your finger moves on the pad. Trackballs, pointing
sticks, and touch pads are easier to use than a mouse for portable computer
users and are thus built into most notebook computer keyboards.
Touch screens are
devices that allow you to use a computer by touching the surface of its video
display screen. Some touch screens emit a grid of infrared beams, sound waves,
or a slight electric current that is broken when the screen is touched. The
computer senses the point in the grid where the break occurs and responds with
an appropriate action. For example, you can indicate your selection on a menu
display by just touching the screen next to that menu item.
PEN-BASED
COMPUTING:
Pen-based computing
technologies are being used in many hand-held computers and personal digital
assistants. These small PCs and PDA’s contain fast processors and software that
recognizes and digitizes handwriting, hand printing, and hand drawing. They
have a pressure sensitive layer like a graphics pad under their slate like liquid crystal display (LCD) screen. So
instead of writing on paper form fastened to a clipboard or using a keyboard
device, you can use a pen to make selections, send E-Mail, and enter
handwritten data directly into a computer.
A variety of other pen
like devices are available. One example is the digitizer pen and graphics
tablet. You can use the digitizer pen as a [pointing device, or use it to draw
or write on the pressure-sensitive surface of the graphics table. Your
handwriting or drawing is digitized by the computer, accepted as input,
displayed on its video screen, and entered into your application.
VOICE
RECOGNITION AND RESPONSE:
Voice recognition
promises to be the easiest method for data entry, word processing, and
conversational computing, since speech is the easiest, most natural means of
human communication. Voice input has now become technologically and
economically feasible for a variety of applications. Early voice recognition
products used discrete speech recognition, where you had to pause each spoken
word. New continuous speech recognition (CSR) software recognizes continuous,
conversationally paced speech.
Voice recognition
systems analyze and classify speech or vocal tract patterns and convert them
into digital codes for entry into a computer system. Typically, voice
recognition systems with large vocabularies require training the computer to
recognize your voice in order to achieve a high degree of accuracy. Training
such system involves repeating a variety of words and phrases in a training
session and using the system extensively. Trained systems regularly achieve a
95 to 99 percent word recognition rate.
Two example of
continuous speech recognition software for word processing are Naturally
Speaking by Dragon Systems and Via Voice by IBM. Minimum requirements are a 133
MHz Pentium class microprocessor,32 MB
of RAM, an industry standard sound card, and 50 MB of available hard disk capacity. The products
have 30,000-word vocabularies expandable to 60,000 words, and sell for less
than $200.Training to 95 percent accuracy takes only a few hours. Longer use,
faster processors, and more memory make 99 percent accuracy possible.
Speaker-independent
voice recognition systems, which allow a computer to under stand a few words
from a voice it has never heard before, are being built into products and used
in a growing number of applications. Examples include voice-messaging
computers, which use voice recognition and voice response software to verbally
guide an end user through the steps of a task in many kinds of activities.
Typically, they enable of applications include computerized telephone call
switching, telemarketing surveys, bank pay-by-phone bill-paying services, stock
quotations services, university registration systems, and customer credit and
account balance inquiries.
Voice recognition
devices in work situations allow operators to perform data entry without using
their hands to key in data or instructions and to provide faster and more
accurate input. For example, manufacturers use voice recognition systems for
the inspection, inventory, and quality control of a variety of products; and
airlines and parcel delivery companies use them for voice-directed sorting of
baggage and parcels. Voice recognition can also help you operate your
computer’s operating systems and software packages through voice input of data
and commands. In addition, some internet browsers can be voice-enabled so you
can send E-mail and surf the World Wide Web via voice recognition.
OPTICAL
SCANNING:
Optical scanning devices
read text or graphics and convent them into digital input for your computer.
Thus, optical scanning enables the direct entry of data from source documents
into a computer system. For example, you can use a com[pact desktop scanner to
scan pages of text and graphics into your computer for desktop publishing and
Web publishing applications. Or you can scan documents of all kinds into your
system and organize them into folders as part of a document management library
system for east reference or retrieve.
There are many types of
optical scanners, but they all employ photoelectric devices to scan the
characters being read. Reflected light patterns of the data are converted into
electronic impulses that are then accepted as input into the computer system.
Compact desktop scanners have become very popular due to their low cost and
ease of use with personnel computer systems. However, larger, more expensive flatbed scanners are faster and provide higher resolution color
scanning.
The credit card billing
operations of credit card companies, banks, and oil companies use a form of
optical scanning called optical character recognition (OCR). OCR
scanners read the characters and codes on credit card receipts, utility bills,
insurance premiums, airline tickets, and other documents. OCR scanners are also
used to automatically sort mail, score tests, and process a wide variety of
forms in business and government.
Devices such as handheld
optical scanning wands are frequently used to read OCR coding on merchandise
tags and other media. Many business applications involve reading bar coding, a
code that utilizes bars to represent characters. One common example is the
Universal Product Code (UPC bas coding that you see on packages of food items
and many other products. For example, the automated checkout scanners found in
supermarkets read UPC bar coding. Supermarket scanners emit laser beams that
are reflected off a UPC bar code. The reflected image is converted to
electronic impulses that are sent ot the in-store computer, where they are
matched with pricing information. Pricing information is returned to the
terminal, visually displayed, and printed on a receipt for the customer.
OTHER INPUT
TECHNOLOGIES:
Magnetic stripe technology
is a familiar form of data entry that helps computers read credit cards. The
dark magnetic stripe on the back of such cards is the same iron oxide coating
as on magnetic tape. Customer account numbers can be recorded on the mag stripe
so it can be read by bank ATMs, credit card authorization terminals, and many
other types of magnetic stripe readers.
Smart cards that
embed a microprocessor chip and several kilobytes of memory into debit, credit,
and other cards are popular in Europe, and becoming available in the United States Holland
The smart debit cards
used in Holland
Digital cameras
represent another fast growing set of input technologies. Digital still cameras
and digital video cameras (digital camcorders) enable you to shoot, store, and
download still photos or full motion video with audio into your PC. Then you
can use image-editing software to edit and enhance the digitized images and
include them in new letters, reports, multimedia presentations, and Web pages.
The computer systems of
the banking industry can magnetically read checks and deposit slips using
magnetic ink character recognition (MICR) technology. Computers can thus sort
and post checks to the proper checking accounts. Such processing is possible
because the identification numbers of the bank and the customer’s account are preprinted on the bottom of the
checks with an iron oxide-based ink. The first bank receiving a check after it
has been written must en-code the amount of the check in magnetic ink on the check’s
lower right-hand corner. The MICR system uses 14 characters (the 10 decimal
digits and 4 special symbols) of a standardized design. Equipment known as
reader-sorters read a check by first magnetizing the magnetic ink characters
and then sensing the signal induced by
each character as it passes a reading head. In this way, data are
electronically captured by the bank’s computer system.
OUTPUT
TECHNOLOGIES AND TRENDS:
Computers provide
information to you in a variety of forms. Figure 4.30 shows you the trends in
output media and methods that have developed over the generations of computing.
As you can see, video displays and printed documents have been, and still are,
the most common forms of output from computer systems. But other natural and
attractive output technologies such as voice response systems and multimedia
output are increasingly found alongwith video displays in business
applications.
VIDEO
OUTPUT:
Video displays are the
most common type of computer output. Most desktop computers rely on video
monitors that use a cathode ray tube
(CRT) technology similar to the picture tubes used in home TV sets. Usually,
the clarity of the video display depends on the type of video monitor you use
and the graphics circuit board installed in your computer. These can provide a
variety of graphics modes of increasing capability. A high-resolution,
flicker-free monitor is especially important if you spend a lot of time viewing
multimedia on CDs, or the Web, or complex graphical displays of many software
packages.
The biggest use of
liquid crystal displays (LCDs) is to provide a visual display capability for
portable microcomputers and PDAs. LCD displays need significantly less electric
current and provide a thin, flat display. Advances in technology such as active
matrix and dual scan capabilities have improved the clarity of LCD displays.
PRINTED
OUTPUT:
Printing information on
paper is still the most common form of output after video displays. Thus, most
personal computer systems rely on an inkjet or laser printer to produce
permanent (hard copy) output in high-quality printed form. Printed output is
still a common form of business communications, and is frequently required for
legal documentation.
Thus, computers can
produce printed reports and correspondence, documents such as sales invoices,
payroll checks, bank statements, and printed versions of graphics displays.
Inkjet printers,
which spray ink onto a page one line at a time, have become the most popular,
low-cost printers for microcomputer systems. They are quiet, produce several
pages per minute of high-quality output, and can print both black-and-white and
high-quality color graphics. Laser printers use an electrostatic process
similar to a photocopying machine to produce many pages per minute of high-quality
black-and-white output. More expensive color laser printers and multifunction
inkjet and laser models that print, fax, scan, and copy are other popular
choices for business offices.
STORAGE
TRENDS AND TRADE-OFFS:
Data and information
must be stored until needed using a variety of storage methods. There are many
types of storage media and devices.
Computer
Storage Fundamentals
Data are processed and
stored in a computer system through the presence or absence of electronic or
magnetic signals in the computer’s circuitry or in the media it uses. This is
called a “two-state” or binary representation of data, since the
computer and the media can exhibit only two possible states or conditions. For
example, transistors other semiconductor circuits are either in a conducting or
nonconducting state. Media such as magnetic disks and tapes indicate these two
states by having magnetized spots whose magnetic fields have one of two
different directions, or polarities. This binary characteristic of computer circuitry
and media is what makes the binary number system the basis for representing
data in computers. Thus, for electronic circuits, the conducting (ON) state
represents the number one, while the nonconducting (OFF) state represents the
number zero. For magnetic media, the magnetic field of a magnetized sport in
one direction represents a one, while magnetism in the other direction
represents a zero.
The smallest element of
data is called a bit, which can have a value of either zero or one. The
capacity of memory chips is usually expressed in terms of bits. A byte is a
basic grouping of bits that the computer operates as a single unit. Typically,
it consists of eight bits and represents one character of data in most computer
coding schemes. Thus, the capacity of a computer’s memory and secondary storage
device is usually expressed in terms of bytes. Computer codes such as ASCII
(American Standard Code for Information Interchange) use various arrangements
of bits to form bytes that represent the numbers zero through nine, the letters
of the alphabets, and many other characters.
Storage capacities are
frequently measured in kilobytes (KB), megabytes (MB), gigabytes (GB), or
terabytes (TB). Although kilo means 1,000 in the metric system, the computer
industry uses K to represents 1,024 or (210) storage positions.
Therefore, a capacity of 10 megabytes, for example, is really 10,485,760
storage positions, rather than 10 million positions. However, such differences
are frequently disregarded in order to simplify descriptions of storage
capacity. Thus, a megabyte is roughly 1 million bytes of storage, while a
gigabyte is roughly 1 billion bytes and a terabyte represents about 1 trillion
bytes.
Direct and
Sequential Access
Primary storage media
such as semiconductor memory chips are called direct access or random access
memories (RAM). Magnetic disk devices are frequently called direct access
storage devices (DASDs). On the other hand, media such as magnetic tapes are
known as sequential access devices.
The term direct access
and random access describe the same concept. They mean that an element of data
or instructions (such as a byte or word) can be directly stored and retrieved
by selecting and using any of the locations on the storage media. They also
mean that each storage position (1) has a unique address and (2) can be
individually accessed in approximately the same length of time without having
to search through other storage positions. For example, each memory cell on a
microelectronic semiconductor RAM chip can be individually sensed or changed in
the same length of time. Also any data record stored on a magnetic or optical
disk can be accessed directly in approximately the same time period.
Sequential access
storage media such as magnetic tape do not have unique storage addresses that
can be directly addressed. Instead, data must be stored and retrieved using a
sequential or serial process. Data are recorded one after another in a
predetermined sequence (such as in numeric order) on a storage medium. Locating
an individual item of data requires searching much of the recorded data on the
tape until the desired item is located.
Semiconductor
Memory
The primary storage
(main memory) of your computer consists of microelectronic semiconductor
memory chips. Memory chips with capacities of 4 million bits (4 megabits)
and 16 megabytes or more of memory chips can be added to your PC to increase
its memory capacity. Specialized memory can help improve your computer’s
performance. Examples include external cache memory of 256 or 512 kilobytes to
help your microprocessor work faster, or a video graphics accelerator card with
2 megabytes or more of RAM for faster and clearer video performance. Removable
credit-card-size and smaller “flash memory” RAM cards can also provide several
megabytes of erasable direct access storage for PDAs or handheld PCs.
Some of the major
attractions of semiconductor memory are its small size, great speed, and shock
and temperature resistance. One major disadvantage of most semiconductor memory
is its volatility. Uninterrupted electric power must be supplied or the
contents of memory will be lost. Therefore, emergency transfer to other devices
or standby electrical power (through battery packs or emergency generators) is
required if data are to be saved. Another alternative is to permanently “burn
in” the contents of semiconductor devices so that they cannot be erased by a
loss of power.
Thus, there are two
basic types of semiconductor memory: random access memory (RAM) and read only
memory (ROM).
v RAM: random access memory. These memory chips
are the most widely used primary storage medium. Each memory position can be
both sensed (read) and changed (written), so it is also called read/write
memory. This is a volatile memory.
v ROM: read only memory. Nonvolatile
random access memory chips are used for permanent storage. ROM can be read but
not erased or overwritten.
Frequently used control
instructions in the control unit and programs in primary storage (such as parts
of the operating system) can be permanently burned in to the storage cells
during manufacture. This is sometimes called firmware. Variations include PROM
(programmable read only memory) and EPROM (erasable programmable read only
memory) that can be permanently or temporarily programmed after manufacture.
Magnetic
Disk Storage
Magnetic disks are the
most common form of secondary storage for your computer system. That’s because
they provide fast access and high storage capacities at a reasonable cost.
Magnetic disk drives contain metal disks that are coated on both sides with an
iron oxide recording material. Several disks are mounted together on a vertical
shaft, which typically rotates the disks at speeds of 3,600 to 7,600
revolutions per minute (rpm). Electromagnetic read/write heads are positioned
by access arms between the slightly separated disks to read and write data on
concentric, circular tracks. Data are recorded on tracks in the form of tiny
magnetized spots to form the binary digits of common computer codes. Thousands
of bytes can be recorded on each tracks, and there are several hundred data
tracks on each disk surface, thus providing you with billions of storage
positions for your software and data.
Types of
Magnetic Disks
There are several types
of magnetic disk arrangements, including removable disk cartridges as well as
fixed disk units. Removable disk devices are popular because they are
transportable and can be used to store backup copies of your data offline for
convenience and security.
·
Floppy disks or magnetic diskettes, consist of
polyester film disks covered with an iron oxide compound. A single disk is
mounted and rotates freely inside a
protective flexible or hard plastic jacket, which has access openings to
accommodate the read/write head of a disk drive unit. The 31/2 inch
floppy disk, with capacities of 1.44 megabytes, is the most widely used
version, with a newer LS-120 technology offering 120 megabytes of storage.
·
Hard disk drives combine magnetic disks,
access arms, and read/write heads into a sealed module. This allows higher
speeds, greater data-recording densities, and closer tolerances within a
sealed, more stable environment. Fixed or removable disk cartridge versions are
available. Capacities of hard drives range from several hundred megabytes to
gigabytes of storage.
·
RAID. Disk arrays of interconnected
microcomputer hard disk drives have replaced large-capacity mainframe disk
drives to provide many gigabytes of online storage. Known as RAID (redundant
arrays of independent disks), they combine from 6 to more than 100 small hard
disk drives and their control microprocessors into a single unit. RAID units
provide large capacities with high access speeds since data are accessed in
parallel over multiple paths from many disks. RAID units also provide a fault tolerant
capability, since their redundant design offers multiple copies of data on
several disks. If one disk fails, data can be recovered from backup copies
automatically stored on other disks.
Magnetic
Tape Storage
Magnetic tape is still
being used as a secondary storage medium in business applications. They
read/write heads of magnetic tape drives record data in the form of magnetized
spots on the iron oxide coating of the plastic tape. Magnetic tape devices
include tape reels and cartridges in mainframes and midrange systems, and small
cassettes or cartridges for PCs. Magnetic tape cartridges have replaced tape
reels in many applications, and can hold over 200 megabytes.
One growing business
application of magnetic tape involves the use of 36-track magnetic tape
cartridges in robotic automated drive assemblies that can hold hundreds of
cartridges. These devices serve as slower, but lower cost, storage to
supplement magnetic disks to meet massive data warehouse and other business
storage requirements. Other major applications for magnetic tape includes
long-term archival storage and backup storage for PCs and other systems.
Optical
Disk Storage
Optical disks are a
fast-growing storage medium. The version for use with micro computers is called
CD-ROM (compact disk- read only memory). CD-ROM technology use 12-centimeter
(4.7 inch) compact disks (CDs) similar to those used in stereo music systems.
Each disk can store more than 600 megabytes. That’s the equivalent of over 400
1.44 megabyte floppy disks or more than 300,000 double-spaced pages of text. A
laser records data by burning permanent microscopic pits in a spiral track on a
master disk from which compact disks can be mass produced. Then CD-ROM disk
drives use a laser device to read the binary codes formed by those pits.
CD-R (compact disk –
record able) is another optical disk technology. It enables computers with CD-R
disk drive units to record their own data once on a CD, then be able to read
the data indefinitely. The major limitation of CD-ROM and CD-R disks is that
recorded data cannot be erased. However, CD-RW
(CD-rewritable) optical disk systems have now become available which record and erase data by using a laser to heat a microscopic point on the disk’s surface. In CD-RW versions using magneto optical technology, a magnetic coil changes the spot’s reflective properties from one direction to another, thus recording a binary one or zero. A laser device can then read the binary codes on the disk by sensing the direction of reflected light.
(CD-rewritable) optical disk systems have now become available which record and erase data by using a laser to heat a microscopic point on the disk’s surface. In CD-RW versions using magneto optical technology, a magnetic coil changes the spot’s reflective properties from one direction to another, thus recording a binary one or zero. A laser device can then read the binary codes on the disk by sensing the direction of reflected light.
Optical disk capacities
and capabilities have increased dramatically with the emergence of an optical
disk technology called DVD (digital video disk or digital versatile disk),
which can hold from 3.0 to 8.5 gigabytes of multimedia data on each side of a
compact disk. The large capacities and high quality images and sound of DVD
technology are expected to eventually replace CD-ROM and CD-RW technologies for
data storage, and promise to accelerate the sue of DVD drives for multimedia
products that can be used in both computers and home entertainment systems.
Software
Trends
Several major software
trends. First, there has been a major trend away from custom-designed programs
developed by the professional programmers of an organization. Instead, the
trends is toward the use of off-the-shelf software packages acquired by end
users from software vendors. This trend dramatically in creased with the
development of relatively inexpensive and easy-to-use application software
packages and multipurpose software suites for microcomputers. The trend has accelerated recently, as
software packages are designed with networking
capabilities and collaboration features that optimize their usefulness
for end users and work grounds on the Internet and corporate intranets and
extranets.
Second, there has been a
steady trend away from (1) technical, machine-specific programming language
using binary-based or symbolic codes, or (2) procedural languages, which use
brief statements and mathematical expressions to specify the sequence of instructions
a computer must perform. Instead, the trend is toward the use of a visual
graphic interface for object-oriented programming, or toward non procedure
natural languages for programming that are closer to human conversation. This
trend accelerated with the creation of easy-to-use, non procedural
forth-generation languages (4GLs). It continues to grow as developments in
object technology, graphics, and artificial intelligence produce natural
language and graphical user interfaces that make both programming tools and
software packages easier to use.
In addition, artificial
intelligence features are now being built into a new generation of
expert-assisted software packages. For example, many software suites provide
intelligent help features called wizards that help you perform common software
functions like graphing parts of a spreadsheet or generating reports from a
database, Other software packages use capabilities called intelligent agents to
perform activities based on instructions from a user. For example, some
electronic mail packages can use an intelligent agent capability to organize,
send, and screen E-mail messages fro your.
These major trends seem
to be converging to produce a fifth generation of powerful, multipurpose,
expert-assisted, and network enabled software package with natural language and
graphical interfaces to support the productivity and collaboration of both end
users IS professionals.
Application
Software for End Users
Application software
includes a variety of programs that can be subdivided into general-purpose and
application-specific categories. Thousands of application-specific
software package are available to support specific applications of end users in
business and other fields. For example, application-specific packages in
business support managerial, professional, and business uses such as
transaction processing, decision support, accounting, sales management,
investment analysis, and electronic commerce. Application-specific software for
science and engineering plays a major role in the research and development
programs of industry and the design of efficient production processes for
high-quality product. Other software packages help end users with personal
fiancé and home management, provide a wide variety of entertainment and
educational products.
General-purpose
application programs are programs that perform common information processing
jobs for end users. For example, word processing programs, spreadsheet
programs, database management programs, and graphics programs are popular with
microcomputer users for home, education, business, scientific, and many other
purposes. Because they significantly increase the productivity of end users,
they are sometimes known as productivity packages. Other examples include Web browsers,
electronic mail, and groupware, which help support communication and
collaboration among workgroups and teams.
Software
Suites and Integrated Packages
Let’s begin our
discussion of popular general-purpose application software by looking at software
suites. That’s because the most widely used productivity package come bundled
together as software suites such as Microsoft Office, Lotus SmartSuite, and
Corel WordPerfect Office. Examining their components gives us an overview of
the important software tools that you can use to increase your productivity,
collaborate with your colleagues, and access intranets, extranets, and the
Internet.
Compares the component
programs that make up the tope three software suites. Notice that each suite
integrates software packages for Web browsing, word processing, spreadsheets,
presentation graphics, database management, personal in formation management,
and more. These packages can be purchased as separate stand-alone products.
However, a software suite costs a lot less than the total cost of buying its
individual package separately.
Another advantage of
software suites is that all programs use a similar graphical user interface
(GUI) of icons, tool and status bars, menus, and so on, which gives them
the same look and feel, and makes them easier to learn and use. Software suites
also share common tools, such as spell checkers and help wizards to
increase their efficiency. Another big
advantage of suites is that their programs are designed to work together
seamlessly, and import each other’s files easily, no matter which program you
are using at the time. These capabilities make them more efficient and easier
to use than using a variety of individual package versions.
 Programs |
Microsoft
|
Lotus SmartSuite
|
Corel WordPerfect Office
|
|
Web
Browser
|
Internet
Explorer
|
N/A
|
Netscape
Navigator
|
|
Word
Procedure
|
Word
|
Word Pro
|
Word
Perfect
|
|
Spreadsheet
|
Excel
|
|
Quattro
Pro
|
|
Presentation
Graphics
|
Power
Point
|
Freelance
|
Presentations
|
|
Database
Manager
|
Access*
|
Approach
|
Paradox
|
|
Personal
Information Manager
|
Outlook
|
Organize
|
Corel
Central
|
|
Others
|
Camcorder*
|
ScreenCam
|
CorelDraw**
|
*Access not
included in the standard edition. Microsoft Publisher, Bookshelf, etc.,
available depending on the suite edition.
**CorelFlow,
TimeLine, Dashboard, etc., available in all versions.
Of course, putting so
many programs and features together in one super-size package does have some
disadvantages. Industry critics argue that many software suite features are
never used by most end users. The suites take up a lot of disk space, from over
100 megabytes to over 150 megabytes, depending on which version or functions
you install. So such software is sometimes derisively called bloatware by its
critics. The cost of suites can vary from as low as $100 for a competitive
upgrade to over $700 for a full version of some editions of the suites.
These drawbacks are one
reason for the continued use of integrated packages like Microsoft Works, Lotus
Works, Claris Works, and so on. Integrated packages combine some of the functions
of several programs word processing, spreadsheets, presentation graphics,
database management, and so on into one software package.
Because Works programs
leave out many features and functions that are in individual packages and
software suites, they cannot do as much as those packages do. However, they use
a lot less disk space (less than 10 megabytes), and cost less than a hundred
dollars. So integrated packages have proven that they offer enough functions
and features for many computer users, while providing some of the advantages of
software suites in a smaller package.
Web
Browsers and More
The most important
software component for many computer users today is the once simple and
limited, but now powerful and feature rich, Web browser. A browser like
Netscape Navigator or Microsoft Explorer is the key software interface you use
to point and click your way through the hyperlinked resources of the World Wide
Web and the rest of the Internet, as well as corporate intranets and extranets.
Once limited to surfing the Web, browsers are becoming the universal software
platform on which end users launch into information searches, E-mail,
multimedia file transfer, discussion groups, and many other Internet, intranet,
and extranet applications.
Industry experts are
predicting that the Web browser wil be the model for how most people will use
networked computers into the next century. So now, whether you want to watch a
video, make a phone call, download some software, hold a video conference,
check your E-mail, or work on a spreadsheet of your team’s business plan, you
can use your browser to launch and host such applications. That’s why browsers
are being called the universal client, that is, the software component
installed on the workstations of all the clients (users) in client/server
networks throughout an enterprise.
The web browser has also
become only one component of a new suite of communications and collaboration
software that Netscape and other vendors are assembling in a variety of
configurations.
Electronic
Mail
The first thing many
people do at work all over the world is check their E-mail. Electronic mail has
changed the way people work and communicate. Millions of end users now depend
on E-mail software to communicate with each other by sending and receiving
electronic messages via the Internet or their organizations’ intranets or
extranets. E-mail is stored on network servers until you are ready. Whenever
you want to your can read your E-mail by displaying it on your workstations.
So, with only a few minutes of effort (and a few microseconds or minutes of
transmission time), a message tone or many individuals can be composed, sent,
and received.
As we mentioned earlier,
E-mail software is now a component of top software suites and some Web
browsers. E-mail packages like Eudora and Pine are typically provided to
Internet users by Internet service providers and educational institutions.
Full-featured E-mail software like Microsoft change E-mail or Netscape
Messenger can route messages to multiple end users based on predefined mailing
lists and provide password security, automatic message forwarding, and remote
user access. They also allow you to store messages in folders with provisions
for adding attachments to messages files. E-mail packages may also enable you
to edit and send graphics and multimedia as well as text, and provide bulletin
board and computer conferencing capabilities. Finally, your E-mail software may
automatically filter and sort incoming messages (even news items from online
services) and route them to appropriate user mailboxes and folders.
Word
Processing and Desktop Publishing
Software for work
processing has transformed the process of writing. Word processing packages
computerize the creation, editing, revision, and printing of documents (such as
letters, memos. And reports) by electronically processing your text data
(words, phrases, sentences, and paragraphs). Top word processing packages like
Microsoft Word, Lotus WordPro, and Corel WordPerfect can privide a wide variety
of attractively printed documents with their desktop publishing capabilities.
These packages can also convert all documents to HTML format for publication as
Web pages on corporate intranets or the World Wide Web.
Word processing packages
also provide advanced features. For example, a spelling checker capability can
identify and correct spelling errors, and a thesaurus feature helps you find a
better choice of words to express ideas. Or you can identify and correct
grammar and punctuation errors, as well as suggest possible improvements in
your writing style, with grammar and style checker functions. Another text
productivity tool is an idea processor or outliner function. It helps you
organize and outline your thoughts before you prepare a document or develop a
presentation. Besides converting documents to HTML format, you can also use the
top packages to design and create Web pages from scratch for an Internet or
intranet Web site.
End users and
organizations can use desktop publishing (DTP) software to produce their
own printed materials that look professionally published. That is, they can
design and print their own newsletters, brochures, manuals, and books with
several type styles, graphics, photos, and colors on each page. Word processing
packages and desktop publishing packages like Adobe PageMaker and QuarkXPress
are used to do desktop publishing. Typically, text material and graphics can be
generated by word processing and graphics packages and imported as text and graphics files.
Optical scanners may be used to input tex
The heart of desktop
publishing is page design process called page makeup or page composition. Your
video screen becomes an electronic pastcup board with rulers, column guides,
and other page design aids. Text material and illustrations are then merged
into the page format your design. The software will automatically move excess
text to another column or page and help size and place illustrations and
headings. Most DTP packages provide WYSIWYG (What You See Is What You Get)
displays so you can see exactly what the finished document will look like before
it is printed.
Electronic
Spreadsheets
Electronic spreadsheet
packages like Lotus 1-2-3 ,
Microsoft Excel, and Corel QuattroPro are used for business analysis, planning,
and modeling. They help you develop an electronic spreadsheet, which is a
worksheet of rows and columns that can be stored on your PC or a network
server, or converted to HTML format and stored as a Web page or websheet on the
World Wide Web. Developing a spreadsheet involves designing its format and
developing the relationships (formulas) that will be used in the worksheet. In
response to your input, the computer performs necessary calculations based on
the relationships (formulas) you defined in the spreadsheet, and displays
results immediately, whether at your workstation or Web site. Most packages
also help you develop graphic displays of spreadsheet results.
For example, you could
develop a spreadsheet to record and analyze past and present advertising
performance for a business. Your could also develop hyperlinks to a similar
websheet at your marketing team’s intranet Web site. Now you have a decision
support tool to help you answer what-if questions you may have about
advertising. For example, “What would happen to market share if advertising
expense increased by 10 percent?” To answer this question, you would imply
change the advertising expense formula on the advertising performance worksheet
your developed. The computer would recalculate the affected figures, producing new market share figures and
graphics. You would then have a better insight on the effect of advertising
decisions on market share. Then you could share this insight with a note on the
websheet at your team’s intranet Web site.
Database
Management
Microcomputer
versions of database management programs have become so popular that they are
now viewed as general-purpose application software packages like work
processing and spreadsheet packages. Database management packages such as
Microsoft Access, Lotus Approach, or Corel Paradox allow you to set up and
manage databases on your PC, network server, or the World Wide Web. Most
database managers can perform four primary tasks, which we will discuss further
in Chapter 7.
·
Database development. Define and
organize the content, relationships, and structure of the data needed to build
a database, including any hyperlinks to data on Web pages.
·
Database interrogation. Access the
data in database to display information in a variety of formats. End users can
selectively retrieve and display information and produce forms, reports, and
other documents, including Web pages.
·
Database maintenance. Add,
delete, update, and correct the data in a database, including hyperlinked data
on Web pages.
·
Application development. Develop
prototypes of Web pages, queries, forms, reports, and labels for a proposed
business application. Or use a built-in 4GL or application generator to program
the application.
Presentation
Graphics and Multimedia
Presentation graphics
packages help you convert numeric data into graphics displays such as line
charts, bas graphs, pie charts, and many other types of graphics. Most of the
top package also help you prepare multimedia presentations of graphics, photo,
animation, and video clips, including publishing to the World Vide Web. Not
only are graphics and multimedia displays earlier to comprehend and
communicate than numeric data but
multiple-color and multiple media displays also can more early emphasize key
points, strategic differences, and important trends in the data. Presentation
graphics has proved to be much more effective than tabular presentations of
numeric data for reporting and communicating in advertising media, management
reports, or other business presentations.
Presentation graphics
software packages like Microsoft PowerPoint, Lotus Freelance, or Corel
Presentations give you many easy-to-use capabilities that encourage the use of
graphics presentations. For example, most packages help you design and manage
computer generated and orchestrated slide shows containing many integrated
graphics and multimedia displays. Or you can select from a variety of
predesigned templates of business presentations, prepare and edit the outline
and notes for a presentation, and manage the use of multimedia files of
graphics, photos, sounds, and video clips. And of course, the top packages help
you tailor your graphics and multimedia presentation for transfer in HTML
format to Web sites on corporate intranets or the World Wide Web.
Multimedia
Technologies
Hypertext and hypermedia
are foundation technologies for multimedia presentations. By definition
hypertext contains only text and a limited amount of graphics. Hypermedia are
electronic documents that contain multiple forms, of media, including text,
graphics, video, and so on. Key terms and topics in hypertext or hypermedia
documents are indexed by software links so that they can be quickly searched by
the reader. For example, if you click your mouse button on an underlined term
on a hypermedia document displayed on your computer video screen, the computer
instantly brings up a display of a passage of text and graphics related to that
term. Once you finish viewing that
pop-up display, you can return to what you were reading originally, or jump to
another part of the document.
Hypertext and hypermedia
are developed using specialized programming languages like Java and the
Hypertext Markup. Language (HTML), which create hyperlinks to other parts of
the document, or to other documents and media. Hypertext and hypermedia
documents can thus be programmed to let a reader navigate through a multimedia
database by following a chain of hyperlinks through various documents. The Web
sites on the World Wide Web of the Internet are a popular example of this
technology. Thus, the use of hypertext and hypermedia provides an environment for
online interactive presentations of multimedia.
Multimedia technologies
allow end users to digitally capture, edit, and combine video with text,
picture, and sound into multimedia business and educational presentations. For
example, an interactive video session for training airline flight attendants
can be produced on CD-ROM disks. It can combine animated graphics displays of
different airplane configuration, presentations graphics of airline statistics,
lists of major topics and facts, video
clips of flight attendants working on various airplanes, and various
announcements and sounds helpful in managing emergencies.
Personal
Information Managers
The personal information
manager (PIM) is a popular software package for end user productivity and
collaboration. PIMs such as Lotus Organizer, Sidekick by Starfish Software, and
Microsoft Outlook help end users store, organize, and retrieve information
about customers, clients, and prospects, or schedule and manage appointments,
meetings, and tasks. The PIM package will organize data you enter and retrieve
information in a variety of forms, depending on the style and structure of the
PIM and the information you want. For example, information can be retrieved as
an electronic calendar or list of appointments, meetings, or other things to
do; the timetable for a project; or a display of key facts and financial data
about customers, clients, or sales prospects.
Personal information
managers are sold as independent programs or are included in software suites,
and vary widely in their style, structure, and features. For example, Lotus
Organizer uses a notebook with tabs format, while Microsoft Outlook organizes
data about people as a continuous A-to-Z list. Most PIMs emphasize the
maintenance of contact lists, that is, customers, clients, or prospects.
Scheduling appointments and meetings and task management are other top PIM
applications. PIMs are now changing to include the ability to access the World
Wide Web as Sidekick does, or provide E-mail capability, as in Microsoft
Outlook. Also, some PIMs use Internet and E-mail features to support team
collaboration by sharing information such as contact lists, task lists, and
schedules with other networked PIM users.
Groupware
Groupware is
collaboration software, that is, software that helps workgroups and teams work
together to accomplish group assignments. Groupware is a fast-growing category
of general-purpose application software that combines a variety of software
features and functions to facilitate collaboration. For example, groupware
products like Lotus Notes, Novell GroupWise, Microsoft Exchange, and Netscape
Communicator and Collabra support collaboration through electronic mail,
discussion groups and databases, scheduling, task management, data, audio and
videoconferencing, and so on.
Groupware products are
changing in several ways to meet the demand for better tools for collaboration.
Groupware is now designed to use the Internet and corporate intranets and
extranets to make collaboration possible on a global scale by virtual teams
located anywhere in the world. For example, team members might use the Internet
for global E-mail, project discussion forums, and joint Web page development.
Or they might use corporate intranets to publish project news and progress reports,
and work jointly on documents stored on Web servers. Collaborative capabilities
are also being added to other software to give them groupware features. For
example, in the Microsoft Office software suite, Microsoft Word keeps track of
who made revisions to each document, Excel tracks all changes made to
spreadsheet, and Outlook lets you keep track of tasks you delegate to other
ream members.
SYSTEM
SOFTWARE: COMPUTER SYSTEM MANAGEMENT
System
Software Overview
System software consists
of programs that manage and support a computer system and its information
processing activities. These programs serve as a vital software interface
between computer system hardware and the application programs of end users.
·
System management programs. Programs
that manage the hardware, software, network, and data resources of the computer
system during its execution of the various information processing jobs of
users. Examples of important system management programs are operating systems,
network management programs, database management systems, and system utilities.
·
System development programs. Programs
that help users develop information system programs and procedures and prepare
user programs for computer processing. Major development programs are
programming language translators and editors, other programming tools, and CASE
(computer-aided software engineering) packages.
Operating
Systems
The most important
system software package for any computer is its operating system. An operating
system is an integrated system of programs that manages the operations of the
CPU, controls the input/output and storage resources and activities of the
computer system, and provides various support services as the computer executes
the application programs of users.
The primary purpose of
an operating system is to maximize the productivity of a computer system by
operating it in the most efficient manner. An operating system minimizes the
amount of human intervention required during processing. It helps your
application programs perform common operations such as accessing a network,
entering data, saving and retrieving files, and printing or displaying output.
If you have any hands-on experience on a computer, you know that the operating
system must be loaded and activated before you can accomplish other tasks. This
emphasized the fact that operating systems are the most indispensable component
of the software interface between users and the hardware of their computer
systems.
Operating
System Functions
An operating system
performs five basic functions in the operation of a computer system: providing
a user interface, resource management, task management, file management, and
utilities and support services.
The User Interface.
The user interface is the part of the operating system that allows you to
communicate with it so you can load program , access files, and accomplish
other tasks. Three main types of user interfaces are the command driven, menu
driven, and graphical user interfaces. The trend in user interfaces for
operating systems and other software is moving away from the entry of brief end
user commands, or even the selection of choices from menus of options. Instead,
the trend is toward an easy-to-use graphical user interface (GUI) that uses
icons, bars, buttons, boxes, and other images. GUIs rely on pointing devices
like the electronic mouse or trackball to make selections that help you get
things done.
Resource Management. An
operating system uses a variety of resource management programs to manage the
hardware and networking resources of a computer system, including is CPU,
memory, secondary storage devices, telecommunications processors, and
input/output peripherals, For example, memory management programs keep track of
where data and programs are stored. They may also subdivide memory into a
number of sections and swap parts of programs and data between memory and
magnetic disks or other secondary storage devices. This can provide a computer
system with a virtual memory capability that is significantly larger than the
real memory capacity of its primary storage unit. So a computer with a virtual
memory capability can process larger programs and greater amounts of data than
the capacity of its memory circuits would normally allow.
File Management.
An operating system contains file management programs that control the
creation, deletion, and access of files of data and programs. File management
also involves keeping track of the physical location of files on magnetic disks
and other secondary storage devices. So operating systems maintain directories
of information about the location and characteristics of files stored on a
computer system’s secondary storage-devices.
Task Management.
The task management programs of an operating system manage the accomplishment
of the computing tasks of end users. They give each task a slice of a CPU’s
time and interrupt the CPU operations to substitute other tasks. Task
management may involve a multitasking capability where several computing tasks
can occur at the same time. Multitasking may take the form of multiprogramming,
where the CPU can process the tasks of several programs at the same time, or
time sharing, where the computing tasks of several users can be processed at
the same time. The efficiency of multitasking operations depends on the
processing power of a CPU and the virtual memory and multitasking capabilities
of the operating system it uses.
New microcomputer
operating systems and most midrange and mainframe operating systems provide a
multitasking capability. With multitasking, end users can do two or more
operations (e.g., keyboarding and printing) or applications (e.g., word
processing and financial analysis) concurrently, that is, at the same time.
Multitasking on microcomputers has also been made possible by the development
of more powerful microprocessors (like the Intel Pentium-II) and their ability
to directly address much larger memory capacities (upto 4 gigabytes). This
allows an operating system to subdivide primary storage into several large
partitions, each of which can be used by a different application program.
In effect, a single
computer can act as if it were several computers, or virtual machines, since
each application program is running independently at the same time. The number
of programs that can be run concurrently depends on the amount of memory that
is available and the amount of processing each job demands. That’s because a
microprocessor (or CPU) can become overloaded with too many jobs and provide
unacceptably slow response times. However, if memory and processing capacities
are adequate, multitasking allows end users to easily switch from one
application to another, share data files among applications, and process some
applications in a background mode typically, background tasks include large
printing jobs, extensive mathematical computation, or unattended
telecommunications sessions.
Popular
Operating Systems.
MS-DOS (Microsoft Disk
Operating System), along with the Windows operating environment, has been the
most widely used microcomputer operating system. It is a single-user,
single-tasking operating system, but was given a graphical user interface and
limited multitasking capabilities by combining it with Microsoft Windows.
Microsoft began replacing its DOS/Windows combination in 1995 with the Windows
95 operating system. Windows 95 is an advanced operating system featuring a
graphical user interface, true multitasking, networking, multimedia, and many
other capabilities. Microsoft plans to ship a Windows 98 version during 1998.
Microsoft introduced
another operating system, Windows NT (New Technology), in 1995. Windows NT is a
powerful, multitasking, multi-user operating system that is being installed on
network servers to manage local area networks and on desktop PCs with
high-performance computing requirements. New Server and Workstation versions
were introduced in 1997. Some industry experts are predicting that Windows NT
Workstation will supplant Windows 95 and 98 in a few years.
OS/2 (Operating
System/2) is a microcomputer operating system from IBM. Its latest version,
OS/2 Warp 4, was introduced in 1996 and provides a graphical user interface,
voice recognition, multitasking, virtual memory, telecommunications, and many
other capabilities. A version for network servers, OS/2 Warp Server, is also
available. Originally developed by AT&T, UNIX now is also offered by other
vendors, including Solaris by Sun Microsystems and AIX by IBM. UNIX is a
multitasking, multiuse, network-managing operating system whose portability
allows it to run on mainframes, midrange computers, and microcomputers. UNIX is
a popular choice for network servers in many client/server computing networks.
The Macintosh System is an operating system from Apple for Macintosh
microcomputers. Now in version 8.0, the system has a popular graphical user
interface as well as multitasking and virtual memory capabilities.
Network
Management Program.
Today’s information
systems rely heavily on the Internet, intranets, extranets, local area
networks, and other telecommunications networks to interconnect end user
workstations, network servers, and other computer systems. This requires a
variety of system software for network management, including network operating
systems, network performance monitors, telecommunications monitors, and so on. These
programs are used by network servers and other computers in network to manage
network performance. Network management programs perform such functions as
automatically checking client PCs and video terminals for input/output
activity, as signing priorities to data communications requests from clients
and terminals, and detecting and correcting transmission errors and other
network problems. In addition, some network management programs function as
middleware to help diverse networks communicate with each other.
Examples of network
management programs include Novell NetWare, the most widely used network
operating system for complex interconnected local area networks. Microsoft’s
Windows NT Server and IBM’s OS/2 Warp Server are two other popular network operating
systems. IBM’s telecommunication monitor CICS (Customer Identification and
Control System) is an example of a widely used telecommunications monitor for
mainframe-based wide area networks. IBM’s NetView and Hewlett-Packard’s Open
View are examples of network management programs for managing several
mainframe-based or midrange-based computer networks.
Database
Management Systems.
A DBMS program helps
organization use their integrated collections of data records and files known
as databases. It allows different user application programs to easily access
the same database. For example, a DBMS makes it easy for an employee database
to be accessed by payroll, employee benefits, and other human resource
programs. A DBMS also simplifies the process of retrieving information from
databases in the form of displays and reports. Instead of having to write
computer programs to extract information, end users can ask simple questions in
a query language. Thus, many DBMS packages provide fourth-generation language
(4GLs) and other application development features. Examples of popular
mainframe and midrange packages are DB2 by IBM and Oracle 8 by Oracle
Corporation.
Other
System Management Programs.
Several other types of
system management software are marketed as separate programs or are included as
part of an operating system. Utility programs, or utilities, are an important
example. Programs like Norton Utilities perform miscellaneous housekeeping and
file conversion functions. Examples include data backup, data recovery, virus
protection, data compression, and file defragmentation. Most operating systems
also provide many utilities that perform a variety of helpful chores for
computer users.
Other examples of system
support programs include performance monitors and security monitors.
Performance monitors are programs that monitor and adjust the performance and
usage of one or more computer systems to keep them running efficiently,
Security monitors are packages that monitor and control the use of computer
systems and provide warning messages and record evidence of unauthorized use of
computer resources. A recent trand is to merge both types of programs into
operating systems like Microsoft’s Windows NT Server, or into system management
software like Computer Associates’ CA-Unicenter, that can manage both mainframe
systems and servers in a data centre.
PROGRAMMING
LANGUAGES.
A programming language
allows a programmer to develop the sets of instructions that constitute a
computer program. Many different programming languages have been developed,
each with its own unique vocabulary; grammar, and use.
Machine
Languages:
Machine Languages (or
first-generation languages) are the most basic level of programming languages.
In the early stages of computer development, all program instructions had to be
written using binary codes unique to each computer. This type of programming
involves the difficult task of writing instructions in the form of strings of
binary digits (ones and zeros) or other number systems. Programmers must have a
detailed knowledge of the internal operations of the specific type of CPU they
are using. They must write long series of detailed instructions to accomplish
even simple processing tasks. Programming in machine language requires
specifying the storage locations for every instruction and item of data used.
Instructions must be included for every switch and indicator used by the
program. These requirements make machine language programming a difficult and
error-prone task.
Assembler
Languages.
Assembler languages (or
second-generation languages) are the next level of programming languages. They
were developed to reduce the difficulties in writing machine language programs.
The use of assembler languages requires language translator programs called assemblers that allow a computer to convert the instructions of such
languages into machine instructions. Assembler languages are frequently called
symbolic languages because symbols are used to represent operation codes and
storage locations. Convenient alphabetic abbreviations called mnemonics (memory
aids) and other symbols represent operation codes, storage locations, and data
elements.
Advantages and
Disadvantages. An assembler language uses alphabetic abbreviations
that are easier to remember in place of the actual numeric addresses of the
data. This greatly simplifies programming, since the programmer does not need
to know the exact storage locations of data and instructions. However,
assembler language is still machine oriented, because assembler language
instructions correspond closely to the machine language instructions of the
particular computer model being used. Also, note that each assembler
instruction corresponds to a single machine instruction, and that the same
number of instructions are required in both illustrations.
Assembler languages are
still widely used as a method of programming a computer in a machine oriented
language. Most computer manufactures provide an assembler language that
reflects the unique machine language instruction set of a particular line of
computers. This feature is particularly desirable to system programmers, who
program system software (as opposed to application programmers, who program
application software), since it provides them with greater control and flexibility
in designing a program for a particular computer. They can then produce more
efficient software, that is, programs that require a minimum of instructions,
storage, and CPU time to perform a specific processing assignment.
High-level
Languages.
High-level Languages (or
third-generation languages) use instructions, which are called statements, that
use brief statements or arithmetic expressions. Individual high-level language
statements are actually macroinstructions; that is,
each individual statement generates several machine instructions when
translated into machine language by high-level language translator programs
called compiler or interpreters.
High-level language statements resemble the phrases or mathematical
expressions required to express the problem or procedure being programmed. The syntax (vocabulary, punctuation, and grammatical rules) and the
semantics (meanings) of such statements do not reflect the internal code of any
particular computer. For example, the computation
X= Y + Z would be programmed in the high-level languages of BASIC and COBOL.
X= Y + Z would be programmed in the high-level languages of BASIC and COBOL.
Advantages and
Disadvantages. A high-level language is obviously easier to learn and
understand than an assembler language. Also, high-level languages have
less-rigid rules, forms, and syntaxes, so the potential for errors is reduced.
However, high-level languages programs are usually less efficient than
assembler language programs and require a greater amount of computer time for
translation into machine instructions. Since most high-level languages are
machine independent, programs written in a high-level language do not have to
be reprogrammed when a new computer is installed, and computer programmers do
not have to learn a new language for each computer they program.
Fourth
Generation Languages.
The term
fourth-generation language describes a variety of programming languages that
are more nonprocedural and conversational than prior languages. These languages
are called fourth generation languages (4GLs) to differentiate them from
machine languages (first generation), assembler languages (second generation),
and high-level languages (third generation).
Most
fourth-generation languages are nonprocedural languages that encourage users
and programmers to specify the results they want, while the computer determines
the sequence of instructions that will accomplish those results. Users and
programmers no longer have to spend a lot of time developing the sequence of
instructions the computer must follow to achieve a result. Thus,
fourth-generation languages have helped simplify the programming process.
Natural languages are 4GLs that are very close to English or other human
languages.
Advantages &
Disadvantages. There are major difference sin the case of use and technical
sophistication of 4GL products, INTELLECT and English Wizard are examples of
natural query languages that impose no rigid grammatical rules, while a query
language like SQL requires concise structured statements. However, the ease of
use of 4GLs is gained at the expense of some loss in flexibility. It is
frequently difficult for an end user to override some of the pre-specified
formats or procedures of 4GLs. Also, the machine language code generated by a
program developed by a 4GL is frequently much less efficient (in terms of
processing speed and amount of storage capacity needed) than a program written
in a language like COBOL. Major failures have occurred in some large
transactions processing applications programmed in a 4GL. These applications
were unable to provide reasonable response times when faced with a large amount
of realtime transaction processing and end user inquiries. However, 4GLs have
shown great success in business applications that do not have a high volume of
transaction processing.
Object-Oriented
Languages.
Object Oriented
programming (OOP) languages have been around since Xerox developed Smalltalk in
the 1960s. However, object-oriented languages like Visual Baisc, C++, and Java
have become major tools of software development. Briefly, while most other
programming languages separate data elements from the procedures or actions
that will be performed upon them, OOP languages tie them together into objects.
Thus, and object consists of data and the actions that can be performed on the
data. For example, an object could be a set of data about a bank customer’s
saving account, and the operations (such as interest calculations) that might
be performed upon the data. Or an object could be data in graphic form such as a video display window, plus the
display actions that might be used upon it.
In procedural languages,
a program consists of procedures to perform actions on each data element.
However, in object-oriented systems, objects tell other objects to perform
actions on themselves. For example, to open a window on a computer video
display, a beginning menu object could send a window object a message to open
and a window will appear on the screen. That’s because the window object
contains the programs code for opening itself.
Object-oriented
languages are easier to use and more efficient for programming the
graphics-oriented user interfaces required by many applications. Also, once
objects are programmed, they are reusable. Therefore, reusability of objects is
a major benefit of object-oriented programming. For example, programmers can
construct a user interface for a new program by assembling standard objects
such as windows, bars, boxes, buttons, and icons. Therefore, most
object-oriented programming packages provide a GUI that supports a “point and
click”, “drag and drop” visual assembly of objects known as visual programming.
HTML and
Java
HTML and Java are two
relatively new programming languages that have become vital tools for building
multimedia Web pages, Web sites, and Web-based applications.
HTML (Hypertext Markup
Language) is a page description language that creates hypertext or hypermedia
documents. HTML inserts control codes within a document at points you can
specify that create links (hyperlinks) to other parts of the document or to
other documents anywhere on the World Wide Web. HTML embeds control codes in
the ASCII text of a document that designate titles, headings, graphics, and
multimedia components, as well as hyperlinks within the document.
Several of the programs
in the top software suites will automatically convert documents into HTML
formats. These include Web browsers, word processing and spreadsheet programs,
database managers, and presentation graphics packages. These and other
specialized HTML editor programs provide a range of features to help you design
and create multimedia Web pages without formal HTML programming.
Java is an
object-oriented programming language created by Sun Microsystems that is
revolutionizing the programming of applications for the World Wide Web and
corporate intranets and extranets. Java is related to the C++ and Objective C
programming languages, but is much simpler and secure, and is computing
platform independent. Java is also specifically designed for real-time,
interactive, Web-based network applications. So Java applications consisting of
small application programs, called applets, can be executed by any computer and
any operating system anywhere in a network.
The case of creating
Java apples and distributing them from network servers to client PCs and
network computers is a major reason for Java’s popularity. Apples can be small
special purpose application programs or small modules of larger application
programs. Applets can reside at Web sites on a network server until needed by
client systems, and are easy to distribute over the Internet or intranets and
extranets. Applets are platform independent too—they can run on Windows, OS/2,
UNIX, and Macintosh systems without modification. So Java is becoming the
programming language alternative to Microsoft’s Active X language for many
organizations internet on capitalizing on the business potential of the
Internet, as well as their own intranets and extranets.
PROGRAMMING
PACKAGES
A variety of software
packages are available to help programmers develop computer programs. For
example, programming language translators are programs that translate other
programs into machine language instruction codes that computers can execute.
Other software packages, such as programming language editors, are called
programming tools because they help programmers write programs by providing a
variety of program creation and editing capabilities.
Language
Translator Programs.
Computer programs
consist of sets of instructions written in programming languages that must be
translated by a language translator into the computer’s own machine language
before they can be processed, or executed, by the CPU. Programming language
translator programs (or language processors) are known by a variety of names.
An assembler translates the symbolic instruction codes of programs written in
an assembler language into machine language instructions, while a compiler
translates high-level language statements.
An interpreter is a
special type of compiler that translates and executes each statement in a
program one at a time, instead of first producing a complete machine language
program, like compilers and assemblers do. Java is an example of an interpreted
language. Thus, the program instruction in Java applets are interpreted and
executed on-the-fly as the applet is being executed by a client PC.
Programming
Tools.
Many language translator
programs are enhanced by a graphical programming interface and a variety of
built-in capabilities or add-on packages. Language translators have always
provided some editing and diagnostic capabilities to identify programming
errors or bugs. However, many language translator programs now include powerful
graphics-oriented programming editors and debuggers. These programs help
programmers identify and minimize errors while they are programming. Such
programming tools provide a computer-aided programming environment or
workbench. Their goal is to decrease the drudgery of programming while
increasing the efficiency and productivity of programmers. Other programming
tools include diagramming packages, code generators, libraries or reusable
objects and program code, and prototyping tools. Many of these same tools are
part of the toolkit provided by computer-aided software engineering (CASE)
packages.
Business
Applications of Telecommunications.
Telecommunications is
the sending of information in any form (e.g., voice, data, text, and images)
from one place to another using electronic or light-emitting media. Data
communications is a more specific term that describes the transmitting and
receiving of data over communication links between one or more computer systems
and a variety of input/output terminals. The terms teleprocessing, telematics,
and telephony may also be used since they reflect the integration of
computer-based information processing with telecommunications and telephone
technology. However, all forms of telecommunications now rely heavily on
computers and computerized devices. For this reason, the broader term
telecommunications can be used as a synonym for data communications activities.
Figure 6.2 illustrates
some of the many possible business applications of telecommunications. It
groups telecommunications applications into the major categories of enterprise
collaboration systems, electronic commerce systems, and internal business
systems. Figure 6.2 also emphasized that these applications rely on the
telecommunications capabilities of the Internet, intranets, extranets, and
other types of enterprise and inter organizational networks.
Internal business
applications of telecommunications depend on a variety of compute networks to
support a company’s business operations. For example, employees may use an
intranet to access benefits information on a human resource department server.
Or a company may link wide area and local area networks so managers can make
inquiries and generate reports from corporate databases stored on network
servers and mainframe systems.
Figure 6.2
Some of the business
Applications
of
tlecommunications. Note
|
|
|
|
electronic commerce,
and internal business
operations.
 |
|
|
|
The Business
Value of Telecommunications.
What business value is
created by the business applications of telecommunications shown in Figure 6.2?
That’s what you need to know as a manager, entrepreneur, or business
professional. A good way to answer this question is shown in Figure 6.3.
Information technology, especially in telecommunications-based business
applications, helps a company overcome geographic, time, cost, and structural
barriers to business success. Figure 6.3 outlines examples of the business value
of these four strategic capabilities of telecommunications and other
information technologies. This figure emphasizes how several applications of
electronic commerce can help a firm capture and provide information quickly to
end users at remote geographic locations at reduced cost, as well as supporting
its strategic organizational objectives.
For example, traveling
salespeople and those at regional sales offices can use the internet,
extranets, and other networks to transmit customer orders from their laptop or
desktop PCs, thus breaking geographic barriers. Point-of-sale terminals and an
online sale transaction processing network can break time barriers by
supporting immediate credit authorization and sales processing.
Teleconferencing can be used to cut costs by reducing the need for expensive
business trips since it allows customers, suppliers, and employees to
participate in meetings and collaborate on joint projects. Finally, electronic
data interchange systems are used by the business to establish strategic
relationships with their customers and suppliers by making the exchange of
electronic business documents fast, convenient, and tailored to the needs of
the business partners involved. We will discuss the strategic business value of
telecommunications applications in Chapter12, for electronic commerce in
Chapter 8, and for enterprise collaboration in Chapter 9.
Trends in
Telecommunications.
Major trends occurring
in the field of telecommunications have a significant impact on management
decisions in this area. You should thus be aware of major trends in
telecommunications industries, technologies, and applications that
significantly increase the decision alternatives confronting the managers of
business organizations. See Figure 6.4.
Industry
Trends.
The
competitive arena for the telecommunications service has changed dramatically
in the United States United
States
Figure 6.4
Major trends in telecommunications.
Industry trends Toward a greater number of competitive
vendors, carriers, alliance, and network services, accelerated by deregulation
and the growth of the Internet.
and
accelerated with the passage of the Telecommunications Act of 1996, and the
tidal wave of Internet users and uses in the 1990s. Now telecommunications
networks and services are available from numerous large and small
telecommunications companies. Thousands of companies offer businesses and
consumers a choice of everything from local and global telephone services to
communications satellite channels, mobile radio, cable TV, cellular phone
servers, and Internet access. See Figure 6.5.
The explosive growth of
the Internet and the World Wide Web has spawned a host of new
telecommunications products, services, and providers. Driving and responding to
this growth, business firms have dramatically increased their use of the
Internet and the Web for electronic commerce and collaboration. Thus, the
service and vendor options available to meet a company’s telecommunications
needs have increased significantly, as have a business manager’s decision-making
alternatives.
The U.S.
Telecommunications Deregulation and Reform Act of 1996 has promoted few
exceptions, the law overturns virtually all U.S. federal regulations that governed which companies could enter which
communications businesses. This encourages the creation of even more
telecommunications companies, telecommunications mergers and alliances, and
telecommunications services. Key changes in the law include:
·
Local telephone companies, including the regional Bell
·
Long-distance telephone companies can enter local
telephone service markets.
·
Local and long-distance telephone companies can expand
into the cable TV business.
·
Cable TV companies can provide local telephone
services.
Technology
Trends.
Open systems with
unrestricted connectivity, using Internet networking technologies as their
technology platform, are the primary telecommunications technology drivers of
the late 1990s. This trend is self-evident in the rapid and continually
changing development of thousands of hardware, software, and networking
products and services. Their primary goal is to promote easy and secure access
by business end users and consumers to the resources of the Internet,
especially the World Wide Web, and corporate intranets and extranets. Web
browser suites, HTML Web page editors, Internet and intranet servers and
network management software, TCP/IP Internet networking products, and network
security fire walls are just a few examples. These technologies are being
applied in many types of business networks and applications, especially those
for electronic commerce and collaboration. This trend has reinforced previous
industry and technical moves toward building client/server networks based on an
open systems architecture.
Open systems are
information systems that use common standards for hardware, software,
applications, and networking. Open systems, like the Internet and corporate
intranets and extranets, create a computing environment that is open to easy
access by end users and their networked computer systems. Open systems provide
great connectivity, that is, the ability of networked computers and other
devices to easily access and communicate with each other and share information.
Any open systems architecture also provides a high degree of network
interoperability. That is, open systems enable the many different applications
of end users to be accomplished using the different varieties of computer
systems, software packages, and databases provided by a variety of
interconnected networks. Frequently, software known as middleware may be used
to help diverse systems work together. Network architectures like the Open
Systems Interconnection (OSI) model of the International Standards Organization
and the Internet’s TCP/IP protocol suite promote open, flexible, and efficient
standards for the development of open telecommunications networks.
Telecommunications is
also being revolutionized by a change from analog to digital network
technologies. Telecommunications has always depended on voice-oriented analog
transmission systems designed to transmit the variable electrical frequencies
generated by the sound waves of the human voice. However, local and global
telecommunications networks are rapidly converting to digital transmission
technologies that transmit information in the form of discrete pulses, as
computers do. This provides (1) significantly higher transmission speeds, (2)
the movement of larger amount of information, (3) greater economy, and (4) much
lower error rates than analog systems. In types of communications (data, voice,
video) on the same circuits.
Another major trend in
telecommunications technology is a change in communications media. Many
telecommunications networks are switching from reliance on copper wire-based
media (such as coaxial cable) and land-based microwave relay systems to fiber optic lines and
communications satellite transmissions. Fiber optic transmission, which user
pulses of laser-generated light, offers significant advantages in terms of
reduced size and installation effort, vastly greater communication capacity,
much faster transmission speeds, and freedom from electrical interference,
Satellite transmission offers significant advantages for organizations that
need to transmit massive quantities of data, audio, and video over global
networks, especially to isolated areas. These trends in technology give
organizations more alternatives in overcoming the limitations of their present
telecommunications systems.
Application
Trends.
The changes in
telecommunications industries and technologies just mentioned are causing a
significant change in the business use of telecommunications. The trend toward
more vendors, services, Internet technologies, and open systems, and the rapid
growth of the Internet, the World Wide Web, and corporate intranets and
extranets, dramatically increases the number of feasible telecommunications
applications. Thus, telecommunications networks are now playing vital and
pervasive roles in electronic commerce, enterprise collaboration, and internal
business applications that support the operations, management, and strategic
objectives of both large and small companies.
An organization’s
telecommunications function is no longer relegated to office telephone systems,
long-distance calling arrangements, and a limited amount of data communications
in local area networks and with corporate mainframes. Instead, it has become an
integral part of local and global computer networks that are used to dramatically
cut costs, shorten business lead times and response time, support electronic
commerce, improve the collaboration of workgroups, develop online operational
processes, share resources, lock in customers and suppliers, and develop new
products and services. This makes telecommunications a more complex and
important decision area for businesses that must increasingly find new ways to
compete in both domestic and global markets.
The
Internet Revolution.
The explosive growth of
the Internet is the revolutionary technology phenomenon of the 1990s. The
Internet has become the largest and most important network of networks today,
and is evolving into the information superhighway of tomorrow. The Internet is
constantly expanding, as more and more businesses and other organizations and
their users, computers, and networks join its global web. Thousands of
business, educational, and research networks now connect millions of computer
systems and users in more than 200 countries to each other. The Internet has
also become a key platform for a rapidly expanding list of information and
entertainment services and business applications, including enterprise
collaboration and electronic commerce systems.
The Internet evolved
from a research and development network (ARPANET) established in 1969 by the
U.S. Defence Department to enable corporate, academic, and government
researchers to communicate with E-mail and share data and computing resources.
The Net doesn’t have a central computer system or telecommunications center.
Instead, each message sent has a unique address code so any Internet server in
the network can forward it to its destination. Also, the Internet does not have
a headquarters or governing body. The Internet Society in Reston , Virginia
The Internet is growing
rapidly. For example, the Internet is more than doubling in size each year,
growing to over 30 million host computers and more than 100million users in
early 1998. The monthly rate of growth of the Internet was estimated at between
7 to 10 percent. Some industry experts expect the Internet to eventually
interconnect more than 1 billion networks.
Internet
Applications.
The most popular
Internet applications are E-mail, browsing the sites on the World Wide Web, and
participating in special-interest newsgroups. Internet E-mail is faster than
many public networks. Messages usually arrive in seconds or a few minutes
anywhere in the world, and can take form of data, text, fax, and video files.
Internet browser software like Netscape Navigator and Microsoft Explorer
enables millions of users to surf the World Wide Web by clicking their way to
the multimedia information resources stored on the hyperlinked pages of
business, government, and other Web sites. Web sites offer information and
entertainment, and are the launch sites for electronic commerce transactions
between business and their suppliers and customers.
The Internet also
provides electronic discussion forums and bulletin board systems formed and
managed by thousands of special-interest newsgroups. Anyone can participate in
discussions or post messages on thousands of topics for other users with the
same interests to read and respond to. Other popular applications include
downloading software and information files and accessing databases provided by
thousands of business, government, and other organizations. Logging on to other
computers on the Internet and holding real time conversations with other
Internet users are also popular uses of the Internet. We will discuss business
uses of the Internet, including electronic commerce.
One of the most
important and popular uses of the Internet is gathering information. You can
make online searches for information in a variety of ways, using your Web
browser and search engines such as Alta Vista, Excite, and directories like
Yahoo! Thousands of Web sites, business and government databases, and catalogs
from university libraries to the Library of Congress are available, as are
electronic versions of numerous consumer, business, and academic publications.
You can point and click your way to thousands of Web sites and their databases,
downloading everything from the latest satellite weather photos from NASA to
world almanac excerpts from the U.S. Central Intelligence Agency.
THE INFORMATION
SUPERHIGHWAY.
The trends toward open,
high-speed, digital networks with fiber optic and satellite links and the
widespread use of the Internet and its technologies have made the concept of an
information superhighway technically feasible and captured the interest
of both business and government. In this concept, local, regional, nationwide,
and global networks will be integrated into a vast network of networks, with
more advanced interactive multimedia capabilities than the Internet. The information
superhighway system would connect individuals, households, businesses, news and
entertainment media, government agencies, libraries, universities, and all
other institutions, and would support interactive voice, data, video, and
multimedia communications.
No comments:
Post a Comment