Technology in Information Systems

Technology in Information Systems

Technology in Information Systems

Ekaaksh Deshpande

Technology in Information Systems

Ekaaksh Deshpande

ISBN - 9789361521751

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Preface

Information Technology (IT) is the use of computers to store, retrieve, transmit, and manipulate data or information. IT is typically used within the context of business operations as opposed to personal or entertainment technologies. IT is considered to be a subset of Information and Communications Technology (ICT). An Information Technology system is generally an information system, a communications system or, more specifically speaking, a computer system – including all hardware, software and peripheral equipment, operated by a limited group of users.

Humans have been storing, retrieving, manipulating, and communicating information since the Sumerians in Mesopotamia developed writing in about 3000 BC, but the term Information Technology in its modern sense first appeared in a 1958 article published in the Harvard Business Review; authors Harold J. Leavitt and Thomas L. Whisler commented that the new technology does not yet have a single established name. We shall call it information technology (IT). Their definition consists of three categories: techniques for processing, the application of statistical and mathematical methods to decision-making, and the simulation of higher-order thinking through computer programs.

This book aims to help you with the concept of Information Technology. The text tells you the basics of all the things about IT and what it has to offer. Students will find this book very easy to comprehend, and it is ideal for everyone who has an interest in Information Technology. This book is here to serve as a guiding light and helps you to bring the best out of you. We hope you enjoy reading it as much as we enjoyed writing it.

Table of Contents

1 Introduction to Information Technology 1

1.1 What is Information Technology? 1

1.2 Who Studies IT? 11

1.3 IT Infrastructure 16

1.4 Exercise 20

2 Binary Numbering System 21

2.1 Numbering Systems 21

2.2 Binary Numbering System 22

2.2.1 Character Representations 26

2.2.2 Binary Operations 27

2.3 Exercise 34

3 Introduction to Operating System Concepts 35

3.1 What Is an Operating System? 35

3.2 Types of operating systems: 36

3.2.1 Single-Tasking and Multi-Tasking 36

3.2.2 Single- and Multi-User 36

3.2.3 Distributed 37

3.2.4 Templated 37

3.2.5 Embedded 37

3.2.6 Real-Time 37

3.2.7 Library 38

3.3 OS Tasks 52

3.3.1 Security 52

3.3.2 Control Over System Performance 53

3.3.3 Job Accounting 54

3.3.4 Error Detecting Aids 54

3.3.5 Memory Management 55

3.3.6 Processor Management 58

3.3.7 Device Management 60

3.3.8 File Management 61

3.4 Booting 65

3.5 Exercise 66

4 History of Computers 68

4.1 Evolution of Computer Hardware 68

4.2 Evolution of Computer Software 100

4.3 Exercise 109

5 Operating Systems History 110

5.1 A History of Unix 110

5.2 A History of Linux 124

5.3 A History of Windows 132

5.4 Exercise 135

6 Networks, Network Software, and the Internet 136

6.1 Networks 136

6.2 Wired technologies 139

6.2.1 Atm Network Interfaces 141

6.2.2 Ethernet Networks 143

6.2.3 Nanoscale Communication Network 150

6.2.4 Personal Area Network 151

6.2.5 Local Area Network 152

6.2.6 Home Area Network 153

6.2.7 Storage Area Network ١٥٤

6.2.8 Campus Area Network 155

6.2.9 Backbone Network 155

6.2.10 Metropolitan Area Network 157

6.2.11 Wide Area Network 157

6.2.12 Enterprise Private Network 158

6.2.13 Virtual Private Network 159

6.2.14 Global Area Network 160

6.3 Network Software 164

6.4 The Internet 166

6.5 Exercise 184

7 Software 185

7.1 Introduction 185

7.2 Types of Software 186

7.2.1 Free Software 186

7.2.2 Open-Source Software 187

7.2.3 Copylefted Software 187

7.2.4 Non Copylefted Free Software 187

7.2.5 Shareware 188

7.2.6 Freeware 188

7.3 Software Management 189

7.4 Services and Servers 192

7.5 Exercise 197

8 Programming 198

8.1 Introduction 198

8.2 Types of Languages 200

8.2.1 Procedural Programming Language 200

8.2.2 Functional Programming 200

8.2.3 Object-Oriented Programming Language 200

8.2.4 Scripting Programming Languages 201

8.2.5 Logic Programming 201

8.2.6 C++ Language 201

8.2.7 C Language 202

8.2.8 Pascal Language 202

8.2.9 Fortran Language 202

8.2.10 Java Language 203

8.2.11 Perl Language 203

8.2.12 Php Language 203

8.2.13 Lisp Language 204

8.2.14 Scheme Language 204

8.3 Scripting Languages 204

8.4 Exercise 208

9 Information 209

9.1 What Is Information? 209

9.2 Data and Databases 216

9.3 Information Assurance and Security 218

9.4 Cryptography 228

9.4.1 Classic Cryptography 232

9.5 Exercise 247

10 Careers in Information Technology 248

10.1 IT Careers 249

10.1.1 Network Administration 249

10.1.2 Systems Administration 251

10.1.3 Web Administration 252

10.1.4 Database Administration 253

10.1.5 Computer Support Specialist 254

10.1.6 IT Management 255

10.2 Exercise 257

Appendix 258

Glossary 260

Index 265

Chapter

1 Introduction to Information Technology

1.1 What is Information Technology?

Information technology (IT) covers any form of technology, that is, any equipment or technique used by a company, institution, or any other organization which handles information. It incorporates computing, telecommunication technologies, and includes consumer electronics and broadcasting as it is getting more and more digitized. Spearheaded by the computer, the decades since the mid-1960s have been characterized by extreme development. Since the late 1970s, cheap microelectronics have permitted the diffusion of these technologies into almost all aspects of daily life and have furthermore almost inextricably cross-fertilized and intermingled their multiple application branches, which include industry, commerce, administration, education, medicine, scientific and professional work, entertainment, and domestic work.

Nations with advanced IT-industries have realized that developing competence in information technologies, including new media, is essential, expensive, and difficult; large-scale IT systems are gaining economic feasibility, and various national research and education programs for stimulating these developments are underway. The fundamental capabilities that usually are perceived as being essential are chip design, production facilities, and a common network infrastructure like the Internet for the storage and transmission of digital multimedia information (including video, audio, and other continuous media data in addition to conventional data and text).

The term information technology was coined by the Harvard Business Review, to make a distinction between purpose-built machines designed to perform a limited scope of functions and general-purpose computing machines that could be programmed for various tasks. As the IT industry evolved from the mid-20th century, computing capability advanced while device cost and energy consumption fell lower, a cycle that continues today when new technologies emerge.

Our lives are awash in information. From the moment we arise each morning, we are surrounded by a seemingly endless array of sources that produce, store, or dispense information. Our alarm clocks are tuned to any one of hundreds of radio broadcast stations that greet us with news, weather, and entertainment. Television offers an equally wide assortment of similar broadcast and cable transmissions. At the breakfast table, for example, we can dine while consulting a single screen for the latest international news, current weather for the U.S. and stock market quotes from Wall Street or the foreign markets. Our telephones—wired or wireless—connect us to any point anywhere on the globe. Millions of conversations like ours flood the channels and airwaves. From our home computers, we can pay our bills and balance our checkbooks, send and receive correspondence, purchase goods and services, and read online magazines and newspapers. Even the appliances in our home keep track of things; in fact, they can be organized to send radio transmissions to exchange information and coordinate their activities.

Overhead silent satellites gather data about the weather, population concentrations, and a host of other subjects. Our own identities are traced by an electronic trail of school transcripts, credit histories, medical records, employment files, and so on. Should these records all disappear in an instant, we would have an unbelievably difficult time persuading others who we are. If you are not convinced of this: Think about the annoyances of merely completing a credit transaction without proper identification. Business is information, and information is business too. At most of our jobs, we spend a significant portion of the workday tending to communications, sifting through reports and records, deciding on what is important and what is not.

We have put in long hours, but very few of us have manufactured goods or products to show for it. What we produce is just as important, though more ephemeral. The financial world of banking is more about the electronic transfer of credits than moving money or gold. Commerce still offers goods and services, but its survival and well-being are no longer measured solely by these material goods and services. Every purchase we make at home or on the road is logged and stored in retail databases. Seasons, cycles, and trends are endlessly plotted and analyzed. Margins of profits and loss are no longer based on inventories, but less tangible things like supply chains. The stock market itself will continue more likely to rise and fall due to reports, indicators, rumors, and predictions than traditional measures like company profits, capital investment, and debt. Everywhere information is the legal tender.

We are living in the Information Age. Our lives, work, and the world are all about information. Computers and digital technology have contributed to this flood of information, and they are the best means by which we can cope with it. In this book, we offer insight and skills for managing information. The key is learning how information is captured, preserved, processed, and exchanged in the digital domain. And, though digital information technology has significant advantages and promise, it also has distinct limitations and liabilities. Mastering the digital domain also means balancing these costs and benefits.

Information, in most instances, is useless unless it is transmitted or communicated. As a species, we have developed natural forms of representing and communicating information: signals and natural languages. But, signs and speech are ephemeral; the present binds them. Perhaps the defining characteristic of our species is that we have developed technologies to extend these and other powers.

Technologies are artificial instruments, processes, or systems that extend our natural capabilities. The wheel, for example, is an extension of the foot as a mode of transportation. Agriculture is an extension of our social institution for gathering food. The microscope and the electric light bulb extend our power of vision into unseen worlds. Technologies also alter and modify our environments. The influences of technologies on society and individuals are sometimes immense and obvious, but these changes can also be subtle and indirect. For example, the invention of the printing press had enormously significant and well-documented effects on the development of the modern world. But, on the other hand, as technologist Marshall McLuhan argued, the invention of the lowly stirrup contributed indirectly to the rise of feudalism in Western Europe.

Of all forms of technology, information technologies are perhaps the most important. From the beginning, humans have extended natural forms of representing and communicating information to incorporate artificial or external forms. Writing, for example, is an artificial form of transmitting and storing the spoken word. As such, writing is a form of information technology. Writing preserves and stores the spoken word externally to the speaker. Thus, it can go beyond the presence of the speaker in both space and time. Indeed, written language can preserve our knowledge and experience beyond our mortality.

Certainly, most of what we have achieved as a civilization would not have been possible without our inheritance of the knowledge of generations that have preceded us. This fact alone, perhaps, makes written language the most significant information technology developed by our species. Yet, information technologies can have shortcomings, liabilities, and even ill consequences. The written word, for example, loses some of the richness of meaning conveyed by the spoken word. (Think of an experience of listening to a talented storyteller.) The written word has saved many but, unfortunately, has also helped condemn many men and women to their deaths unjustly. The bottom line is that technologies can yield both good and bad.

Figure 1.1 Information Technology. Source: (https://blnk.in/Fc0DHb)

Electronic digital information technology is the latest generation of information technologies. But, it represents a different brand of information technology. Previously, new information technologies have often competed with and replaced existing ones. The telephone replaced the telegraph for obvious reasons. Television has relegated radio to a subordinate niche. Digital information technology is different because it is a form of technology that extends other technologies. In short, digital information technology can imitate other technologies. Electronic printed documents mimic conventional typeset ones. Digital audio recordings reproduce sounds like their analog counterparts. To the listener, wireless digital telephony works like a normal (wired) telephone service. But its imitation is not mere replication.

Digital information technologies offer value-added features. Electronic documents, for example, can be automatically scaled for different media. The same content can be printed on paper, posted on the World Wide Web, transmitted to handheld personal digital assistants (PDAs) and cell phone screens with no extra formatting or fuss. Electronic databases—unlike conventional ones—can be searched and queried automatically revealing facts that would be difficult to find otherwise. Finally, digital information technology can extend the technologies that it imitates by merging them in new and interesting ways. The Web, for example, merges text, numeric data, images, sounds, and video into a seamless medium for posting and sharing content-rich documents. In support of what we are arguing, consider the rapid acceptance of digital information technologies in so many different areas and enterprises. As a species, we are a conservative lot. Only a few of us are automatically attracted to new things just because of their novelty. Most of us feel more comfortable with the familiar.

On the other hand, we will adapt to and adopt those things that we perceive as us genuinely valuable. Digital information technology must be a case in point. Consider how quickly we have adopted it in so many forms. Would you be willing to give up the Web? E-mail? Indeed the world of information is going digital. The evolution of digital forms of information has influenced the workplace, the marketplace, our schools, and our homes. In some instances, the changes have been dramatic; in others, they have been subtle—almost imperceptible. Considered together, these changes have been highly significant, helping to redefine how we think about and use the information to communicate with each other. An important goal in this book is to guide your exploration of what we call the digital domain. For the time being, consider these examples of the inroads that digital information technology has made in a few short years.

A computer system is not merely a tool but rather itself a medium for representing, storing, manipulating, and communicating different forms of information: text, numbers, graphics, images, sounds, and video. The common denominator for these different forms of information is that they all can be digitized for use by our computers. This data can be studied, combined, transformed, and transmitted with an apparent ease that belies the true complexities of these tasks. Digitized data and the systems that handle it constitute the digital domain.

We usually think of computers as tools. We use computers to do this and that. One of the goals of this book is to convince you that a computer system is a medium, not just a helper or instrument. A medium is a vehicle or agent for something. For example, the air is the medium for sound; writing is a medium for words and thoughts. The computer is a medium for ideas and information. Computers can be used not only to express but communicate these ideas as well. They can store knowledge and facts. But more importantly, computer systems can store and manipulate information in many different forms.

Informational media include text, illustrations, photographs, animation, video, sounds, voice, and music. The modern computer is an all-purpose medium for informational media. Regardless of the media, the computer system represents stores and transmits all in its native digital form. That a computer converts text and graphics, for example, to a digital format means that it can process them in a similar fashion and at the same time. Multimedia refers to the integration of various forms of information, such as text, graphics, sound, and images. A modern computer system is a multimedia machine; that is, it is capable of integrating two or more conventional forms of informational media in a single electronic document. Because we can express and combine various forms of information using a computer, we can interact, explore, and learn even more from that information. In this way, the computer becomes a vehicle for knowledge rather than just a tool that stores, distributes, and displays information.

This book describes how the computer can be used to create, express, and communicate ideas in various forms. Some of the ideas discussed in this book are new and evolving; others are as old as the advent of electronic digital computers more than fifty years ago. After all, modern computer systems are electronic digital machines; they have always had this capability for combining and transmitting informational media. However, desktop or personal computers have only recently had the power to exploit these capabilities for both multimedia and data communications over networks.

The remarkable advances in the price/performance ratio of computer hardware over the past few years, together with a new generation of computer software, are driving dramatic developments in this innovative computer use. In the early days of computing, it was recognized that the speed of computers was especially useful for processing large amounts of numeric and text information. Today, developments in software and hardware are creating opportunities to exploit the computer’s capabilities for representing and processing different, richer forms of information that enhance our intellectual abilities. Thus, the traditional model of employing computation for numbers and text is being replaced by a new paradigm. At the heart of these developments is the emergence of two primary technologies: the ability of modern desktop computer systems to collect, store, retrieve, display, and generally manage information in a variety of media and the possibilities for cooperative work using fully interconnected computers and computer networks.

Computer networks are also playing a dominant role in integrating technology into our lives. Networks connect computers in our offices and labs; they also can link us to other computers across the nation and around the world. Using networks, computer systems can share resources and information. That many forms of information can be exchanged instantaneously over long distances has changed the way we work and play. For example, employees in many corporations and other organizations rely more on electronic mail than conventional mail for communication with co-workers. Indeed, networks have created a new habitat, commonly called cyberspace. These new opportunities have a profound effect on the ways we work and interact with one another. Not only is information more readily available, but it is also