Technology Principles PDF

SYLLABI PRINCIPLES OF INFORMATION TECHNOLOGY Syllabi Page Number Unit I : 1-15 Information Technology: Introduction Information systems Definitio...

SYLLABI PRINCIPLES OF INFORMATION TECHNOLOGY Syllabi Page Number Unit I : 1-15 Information Technology: Introduction Information systems Definition of computer and system Software and Data - IT in business and Industry IT in the Home and at Play It in Education and Training IT in Entertainment and the Arts IT in Science, Engineering, and Mathematics Global Positioning System(GPS). Unit II: 16-42 Introduction to Computers, History of computers, Types of computers, Characteristics of computers, Basic Anatomy of a computer, Applications of computer Memory Memory types. Unit III: 43-62 Software- Kinds of Software - The five types of Applications software - Word processing Spreadsheets - Database software, Presentation graphics software - Communications software- System Software Operating system - functions. Unit IV : 63-82 Computer Networks: Introduction Definition Computer Networks - Types of Networks Local Area Network Metropolitan Area Network - Wide Area Network Personal Area Network - internet Intranet firewalls - Network Topology Bus Ring Hybrid Star. Unit V: 83- 116 Basic Internet Concepts: Analog and Digital Signals - modems and communication Software, ISDN lines, and Cable Modems - Definition of Internet - The World Wide Web - Connecting to the Internet Browsing the web Web browser Uniform Resource Locator (URL) E-mail communication. Unit VI : 117-130 Internet address - Domain Name System (DNS) Locating information on the net Internet Search Engines Chatting and conferencing on the Internet Online Chatting Messaging Usenet Newsgroup.  UNIT I INTRODUCTION TO INFORMATION TECHNOLOGY Structure 1.1Introduction 1.2 Information systems 1.3 Definition of computer and system 1.4 Software and Data 1.5 IT in business and Industry 1.6 IT in the Home and at Play 1.7 IT in Education and Training 1.8 IT in Entertainment and the Arts 1.9 IT in Science, Engineering, and Mathematics 1.10 Global Positioning System. 1. INFORMATION TECHNOLOGY 1.1 INTRODUCTION: 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). 1.2 Information System An information system is a set of interrelated components that collect, manipulate, store data and disseminate information and provide a feedback mechanism to monitor performance. An Information system (IS) is a formal, sociotechnical, organizational system designed to collect, process, store, and distribute information. 1 In a sociotechnical perspective, information systems are composed by four components: task, people, structure (or roles), and technology. 1.3 Computer and System A computer system is a set of integrated devices that input, output, process, and store data and information. Computer systems are currently built around at least one digital processing device. There are five main hardware components in a computer system: Input, Processing, Storage, Output and Communication devices. 1.4 Software and Data Software Software is a set of instructions, data or programs used to operate computers and execute specific tasks. Opposite of hardware, which describes the physical aspects of a computer, software is a generic term used to refer to applications, scripts and programs that run on a device. 2 Data Data is a set of values of subjects with respect to qualitative or quantitative variables. Data is raw, unorganized facts that need to be processed. When data is processed, organized, structured or presented in a given context so as to make it useful, it is called information. 1.5 IT IN BUSINESS & INDUSTRY Information technology fosters innovation in business. Innovation results in smarter apps, improved data storage, faster processing, and wider information distribution. Innovation makes businesses run more efficiently. And innovation increases value, enhances quality, and boosts productivity. IT in banking Information technology in banking sector refers to the use of sophisticated information and communication technologies together with computer science to enable banks to offer better services to its customers in a secure, reliable and affordable manner and sustain competitive advantage over other banks. Banking without computers can't be imagined. A lot of work is done in the computers from transactions to maintaining records. Recurring deposits (e-RD), Fixed deposits (e-FD), money transfer from one account to another (NEFT, RTGS), online transactions are done using the Internet. IT in insurance 3  Insurance companies use a computer to store data of their clients. It manages their data and gives them timely notifications for their premium. It allows the user to get a good knowledge over their policy. IT in marketing The computer is very much needed in marketing. The computer is used to create sell advertisements. It is used to monitor the performance of the product in the market. different illustrations can be made to present the product in an effective and decorative way. Advertising - With computers, advertising professionals create art and graphics, write and revise copy, and print and disseminate ads with the goal of selling more products. Home Shopping - Home shopping has been made possible through use of computerized catalogues that provide access to product information and permit direct entry of orders to be filled by the customers. IT in BPO services Business Process Outsourcing (BPO) services mean those business operations which are performed by an outside service provider. In other words, you can say that some industries take help from other service providers to facilitate their work. They heir some outsourcing companies for that work and those outsourcing companies is called BPO (Business Process Outsourcing). 4 Some of the BPO services are as follows: (a) Financial and Accounting Services (b) Taxation and Insurance Services (c) E-Publishing and Web Promotion (d) Legal Services and Content Writing (e) Multimedia and Design Services (f) Document Management Services (g) Software Testing Services (h) Health Care Services 1.6 IT IN HOME & AT PLAY: Information technologies aid us in doing chores at home in three principal ways: (1) by controlling the appliances we use for housework, (2) by establishing local networks for home communications and control, and (3) by directly providing electronic information and transaction services from the home. Using the right kind of technology/games/activities can support the development of your child's learning and skills, including fine motor skills, letter/ number/ shape/ colour recognition, eye-hand co-ordination, reading, writing, planning, problem solving etc. 5 IT in home computing: We use a PC (personal computer) at our home. The computer is used in our homes for surfing the internet, making presentations, video, games, etc. IT in everyday life: In our daily life, most of the equipment we are using is embedded with software. Microwave has its own software to maintain the temperature and also washing machines, the set-top box has software to interact with us and give us a good experience. 1.7 IT IN EDUCATION, WORKPLACE AND TRAINING: Using information technology in education has made it possible for students to keep on learning, irrespective of where they are. Teachers and professors can send assignments to students and they can complete and submit them even without physically stepping into the classrooms and so learning never has to stop. IT in library Nowadays managing books in the library is not such tough work. Libraries are now computerised. To manage a lot of books barcodes can be associated with books which make the process easy to keep track of the list of available books and many more. IT in education Information technology IT is very much used in education for teaching-learning processes. The software and Hardware made 6 the process of learning very easy. We can see a lot of animations in educational videos which made studying very interesting. Various methods of illustrations are now brought to visualize what we are reading in the real world. a) IT in the classroom IT can be used in various ways in schools to handle online classes. -learning classrooms; -board presentations; (b) Education anywhere anytime A lot of books and educational content are now digitalized. We can get the content whenever we want. Our government is also providing websites to access NCERT books online. (c) Teaching aids and media IT is used mostly as a teaching aid in schools to use pictures, animations and audio-visuals to explain subjects that are difficult to explain, make the lessons interesting using presentations and organize lessons using the computer. (d) Learning Management System (LMS) 7  A Learning Management System (LMS) is being used by many schools to manage their school system. This system is very useful for managing attendance and result. Is well designed to record students' data in an effective way. IT at workplace All the offices are equipped with computers for office automation using various softwares like Microsoft word, Excel and Powerpoint. Most of the work is now done on computers. in offices computers and software makes their work very easy and fast. IT play an important role in e-governance. Some major fields in this category are: Budgets Sales tax department Income tax department Male/Female ratio Computerization of voters lists Computerization of driving licensing system Computerization of PAN card Weather forecasting 1.8 IT IN ENTERTAINMENT & ARTS: Entertainment technology helps us relax and enjoy some free time. The latest technology has been revolutionized daily entertainment. Old ways such as recording on records, tapes, and 8 CDs, have made music across the world. Movies are brought into living rooms through photography, film, and video. IT has substantially changed the field of Graphics Arts. IT provides a variety of new media for many different artists. Digital still photography and video are now becoming commonplace. Computers provide powerful tools for editing such photographs and video. IT in Entertainment One can now download movies, play games, chat, video calls using mobiles and computers. Digital broadcasting has opened a door to the world. It changed the television experience. digital programs are now more interactive and use very much graphics designing. IT in Communication In communication, IT has a significant role. One can easily chat through various platforms. Video calling has now become easier. IT has really changed the way of communication. 9 1.9 IT IN SCIENCE, ENGINEERING AND MATHEMATICS To use the technology correlatively, for example, data processing, simulation techniques, mathematical model and database etc. Through the process of establishing the mechanism model, using a computer data analysis process in materials science, the model predicts the optimal design to achieve. One of major areas is CAD Computer aided design. That provides creation and modification of images To do complex scientific calculations, Computer-Aided Design (CAD) or Computer-Aided Manufacturing (CAM) Scientists and engineers use software applications. It made their work easy. drawing and calculation became very easy. Some fields of engineering and mathematics are: Structural Engineering - Requires stress and strain analysis for design of Ships, Buildings, Budgets, Airplanes etc. Industrial Engineering - Computers deal with design, implementation and improvement of integrated systems of people, materials and equipment. Architectural Engineering - Computers help in planning towns, designing buildings, determining a range of buildings on a site using both 2D and 3D drawings Discrete mathematics provides an important foundation for all areas of computer science. Discrete math is used in various areas including computer architecture, algorithms, computer systems, databases, functional programming, distributed systems, machine learning, operating systems, computer security, and networks. There are also many mathematical and statistical software are used to solve the problems. 10 IT in health care Our hospitals are now computerised a lot of healthcare activities are now monitored by computers. Some of the high-level gadgets are made to serve in hospitals. (i) Computerised Axial Tomography Machine (CAT): Using this machine three-dimensional (3D) images of different parts of the body can be made. These images are helpful in the diagnosis of diseases. (ii) MRI (Magnetic Resonance Imaging Machine): MRI machines are used to provide an image of the internal organs of the body by using strong magnetic fields and radio waves. The digital images are very helpful in the detection of the disease. (iii) Electrocardiogram (ECG) Machine: This machine is used to monitor the heartbeat of a person. This machine records the electrical impulse. (iv) Cardiac Screening Machine: This machine is used to detect the problems related to the heart. It monitors the internal working of the heart. (v) EEG (Electro encephalography) Machine: The Electro encephalography machine is used to record the activities of the brain. This machine works both in the patient is sleeping of awake. Blood Sugar Testing Machine is used to check the sugar level in blood and Blood Pressure can be checked digitally by the blood pressure measuring machine. 11 1.10 GLOBAL POSITIONING SYSTEM: 1.10.1 Introduction to Global Positioning Systems The Global Positioning System (GPS) is a worldwide radio- navigation system formed from a constellation of 24 satellites and their ground stations. Global Positioning System (GPS) is a navigation system using satellites, a receiver and algorithms to synchronize location, velocity and time data for air, sea and land travel. A GPS system consists of a network of 24 orbiting satellites, called NAVSTAR (Navigation System with Time and Ranging), and placed in space in six different orbital paths with four satellites in each orbital plane and covering the entire earth under their signal beams. Fig Global positioning system 1. The orbital period of these satellites is twelve hours. 2. The satellite signals can be received anywhere and at any time in the world. 3. The spacing of the satellites is arranged such that a minimum of five satellites are in view from every point on the globe. 12  4. The first GPS satellite was launched in February 1978. 5. Each satellite is expected to last approx 7.5 years, and replacements are constantly being built and launched into orbit. 6. Each satellite is placed at an altitude of about 10,900 nautical miles and weights about 862 kg. 7. The satellites extend to about 5.2m (17ft) in space including the solar panels. Each satellite transmits on three frequencies. 8. The GPS is based on well known concept called the triangulation technique. History of the Global Positioning System (GPS) 1957 - Soviet Union launched Sputnik I satellite. 1960s - U.S. Navy tracked U.S. submarines with satellite navigation. 1978 - NAVSTAR Block I GPS satellite was launched. 1983 - U.S. announced that it will make GPS available for civilian use after Korean Air flight 007 shot down. 1989 - Magellan introduced NAV 1000, the first hand-held GPS device. First Block II satellite is launched. 1993 - Constellation of 24 satellite system became operational. 1995 - Full Operational Capability (FOC) declared. 2000 - Selective Availability discontinued by the U.S. Government. 2004 - Qualcomm successfully completed test of live assisted GPS on a mobile phone. 2008 - Block II satellite launched. 2016 - GPS IIF satellite launched. 13 Beneficiaries of GPS At the start, more than 1000 portable commercial GPS receivers were purchased for military use. They were carried by soldiers and attached to vehicles, helicopters, and aircraft instrument panels. GPS receivers were used in several aircrafts, including B-2 bombers and F-16 fighters etc. Navy ships used them for rendezvous, minesweeping, and aircraft operations. GPS has become important for all military operations and weapons systems. In additions, GPS benefits non-military operations. GPS is used on satellites to obtain highly accurate orbit data and to control spacecraft orientation. What is WASS? Wide Area Augmentation System (WAAS) is a system of satellites and ground stations that provide GPS signal corrections, giving you even better position accuracy. How much better? Try an average of up to five times better. A WAAS-capable receiver can give you a position accuracy of better than three meters, 95 percent of the time. As long as your GPS system is WAAS enabled you do not need any additional equipment or pay any service fees. 14 Three Components to GPS 1. Space Segment the satellites orbiting the earth and transmitting timing and ranging messages. 2. User Segment - the handheld or other receivers used to interpret the messages broadcast from the Satellites 3. Control Segment - monitors the health and position of the satellites in the space segment and transmits correction information back up to the satellite. Books for Reference: 1. Dennis P.Curtin, Kim dolwy, KunL AWN, Xrhleen morin, Information Technology, the breaking wave, TMH 2000. 2. Stacey C Sawyer, Brain K Williams, Sarah E Hutchinson Using Information Technology Brief Version A Practical Introduction to Computer and Communications Third Edition, McGraw Hill Companies 2011. 3. Introduction to Information systems. 16th edition, 2005. 15  UNIT II FUNDAMENTALS OF COMPUTERS Structure 2.1 Introduction to Computers 2.2 History of computers 2.2.1 Generations of Computers 2.3 Types of computers 2.4 Characteristics of computers 2.5 Basic Anatomy of a computer 2.6 Applications of computer 2.7 Computer Memory and its types 2.1 INTRODUCTION TO COMPUTERS: A computer is an electronic device, operating under the control of instructions stored in its own memory that can accept data (input), process the data according to specified rules, produce information (output), and store the information for future use1. Any kind of computers consists of Hardware and Software. What is a computer? A computer is an electronic device that manipulates information, or data. It has the ability to store, retrieve, and process data. You may already know that you can use a computer to type documents, send email, play games, and browse the Web. You can also use it to edit or create spreadsheets, presentations, and even videos. A computer is designed to execute applications and provides a variety of solutions through integrated hardware and software components. It works with the help of programs and represents the decimal numbers through a string of binary digits. It also has a 16 memory that stores the data, programs, and result of processing. The components of a computer such as machinery that includes wires, transistors, circuits, hard disk are called hardware. Whereas, the programs and data are called software. It is believed that the Analytical Engine was the first computer which was invented by Charles Babbage in 1837. It used punch cards as read-only memory. Charles Babbage is also known as the father of the computer. The basic parts without which a computer cannot work are as follows: 1. Processor: It executes instructions from software and hardware. 2. Memory: It is the primary memory for data transfer between the CPU and storage. 3. Motherboard: It is the part that connects all other parts or components of a computer. 4. Storage Device: It permanently stores the data, e.g., hard drive. 5. Input Device: It allows you to communicate with the computer or to input data, e.g., a keyboard. 6. Output Device: It enables you to see the output, e.g., monitor. Processor Output Mother Device Board Computer Parts Storage Memory Device Input Device 17 2.2 History of Computers: Charles Babbage, an English mechanical engineer and polymath, originated the concept of a programmable computer. Considered the "father of the computer", he conceptualized and invented the first mechanical computer in the early 19th century.... The machine was about a century ahead of its time. Abacus The history of computer begins with the birth of abacus which is believed to be the first computer. It is said that Chinese invented Abacus around 4,000 years ago. It was a wooden rack which has metal rods with beads mounted on them. The beads were moved by the abacus operator according to some rules to perform arithmetic calculations. Fig 2.1 Abacus Napier's bones It was a manually-operated calculating device which was invented by John Napier (1550-1617) of Merchiston. In this calculating tool, he used 9 different ivory strips or bones marked 18 with numbers to multiply and divide. So, the tool became known as "Napier's Bones. It was also the first machine to use the decimal point. Difference Engine In the early 1820s, it was designed by Charles Babbage who is known as "Father of Modern Computer". It was a mechanical computer which could perform simple calculations. It was a steam driven calculating machine designed to solve tables of numbers like logarithm tables. Fig 2.2 Difference Engine 2.2.1 GENERATIONS OF COMPUTERS A generation of computers refers to the specific improvements in computer technology with time. In 1946, electronic pathways called circuits were developed to perform the counting. It replaced the gears and other mechanical parts used for counting in previous computing machines. In each new generation, the circuits became smaller and more advanced than the previous generation circuits. The 19 miniaturization helped increase the speed, memory and power of computers. There are five generations of computers which are described below; First Generation Computers The first generation (1946-1959) computers were slow, huge and expensive. In these computers, vacuum tubes were used as the basic components of CPU and memory. These computers were mainly depended on batch operating system and punch cards. Magnetic tape and paper tape were used as output and input devices in this generation.Some of the popular first generation computers are; ENIAC (Electronic Numerical Integrator and Computer) EDVAC (Electronic Discrete Variable Automatic Computer) UNIVACI (Universal Automatic Computer) IBM-701 IBM-650 Second Generation Computers The second generation (1959-1965) was the era of the transistor computers. These computers used transistors which were cheap, compact and consuming less power; it made transistor computers faster than the first generation computers. In this generation, magnetic cores were used as the primary memory and magnetic disc and tapes were used as the secondary storage. Assembly language and programming languages like COBOL and FORTRAN, and Batch processing and multiprogramming operating systems were used in these computers. Some of the popular second generation computers are; IBM 1620 20  IBM 7094 CDC 1604 CDC 3600 UNIVAC 1108 Third Generation Computers The third generation computers used integrated circuits (ICs) instead of transistors. A single IC can pack huge number of transistors which increased the power of a computer and reduced the cost. The computers also became more reliable, efficient and smaller in size. These generation computers used remote processing, time- sharing, multi programming as operating system. Also, the high- level programming languages like FORTRON-II TO IV, COBOL, PASCAL PL/1, ALGOL-68 were used in this generation. Some of the popular third generation computers are; IBM-360 series Honeywell-6000 series PDP(Personal Data Processor) IBM-370/168 TDC-316 Fourth Generation Computers The fourth generation (1971-1980) computers used very large scale integrated (VLSI) circuits; a chip containing millions of transistors and other circuit elements. These chips made this generation computers more compact, powerful, fast and affordable. These generation computers used real time, time sharing and distributed operating system. The programming languages like C, C++, and DBASE were also used in this generation. 21 Some of the popular fourth generation computers are; DEC 10 STAR 1000 PDP 11 CRAY-1(Super Computer) CRAY-X-MP(Super Computer) Fifth Generation Computers In fifth generation (1980-till date) computers, the VLSI technology was replaced with ULSI (Ultra Large Scale Integration). It made possible the production of microprocessor chips with ten million electronic components. This generation computers used parallel processing hardware and AI (Artificial Intelligence) software. The programming languages used in this generation were C, C++, Java,.Net, etc. Some of the popular fifth generation computers are; Desktop Laptop Notebook Ultra Book Chrome Book 2.3 Types of Computers: Computers are divided into different types based on different criteria. Based on the size, a computer can be divided into five types: 1. Micro Computer 2. Mini Computer 3. Mainframe Computer 22  4. Super Computer 5. Workstations 1. Micro Computer: It is a single-user computer which has less speed and storage capacity than the other types. It uses a microprocessor as a CPU. The first microcomputer was built with 8-bit microprocessor chips. The common examples of microcomputers include laptops, desktop computers, personal digital assistant (PDA), tablets, and Smartphone. Microcomputers are generally designed and developed for general usage like browsing, searching for information, internet, MS Office, social media, etc. 2. Mini Computer Mini-computers are also known as "Midrange Computers." They are not designed for a single. They are multi-user computers designed to support multiple users simultaneously. So, they are generally used by small businesses and firms. Individual departments of a company use these computers for specific purposes. For example, the admission department of a University can use a Mini-computer for monitoring the admission process. 3. Mainframe Computer: It is also a multi-user computer capable of supporting thousands of users simultaneously. They are used by large firms and government organizations to run their business operations as they can store and process large amounts of data. For example, Banks, universities, and insurance companies use mainframe computers to store the data of their customers, students, and policyholders, respectively. 23  Fig. Main Frame computer 4. Super Computer: Super-computers are the fastest and most expensive computers among all types of computers. They have huge storage capacities and computing speeds and thus can perform millions of instructions per second. The super-computers are task-specific and thus used for specialized applications such as large-scale numerical problems in scientific and engineering disciplines including applications in electronics, petroleum engineering, weather forecasting, medicine, space research and more. For example, NASA uses supercomputers for launching space satellites and monitoring and controlling them for space exploration. 5. Work stations: It is a single-user computer. Although it is like a personal computer, it has a more powerful microprocessor and a higher- quality monitor than a microcomputer. In terms of storage capacity and speed, it comes between a personal computer and minicomputer. Work stations are generally used for specialized applications such as desktop publishing, software development, and engineering designs. 24 2.4 Characteristics of computers The characteristics of computers include the following; Speed. Accuracy. Diligence Versatility Reliability Automation Memory Speed A computer works with much higher speed and accuracy compared to humans while performing mathematical calculations. Computers can process millions (1,000,000) of instructions per second. The time taken by computers for their operations is microseconds and nanoseconds. Accuracy Computers perform calculations with 100% accuracy. Errors may occur due to data inconsistency or inaccuracy. 25 Diligence A computer can perform millions of tasks or calculations with the same cons or lack of concentration. Its memory also makes it superior to that of human beings. Versatility Versatility refers to the capability of a computer to perform different kinds of works with same accuracy and efficiency. Reliability A computer is reliable as it gives consistent result for similar set of data i.e., if we give same set of input any number of times, we will get the same result. Automation Computer performs all the tasks automatically i.e. it performs tasks without manual intervention. Memory A computer has built-in memory called primary memory where it stores data. Secondary storage are removable devices such as CDs, pen drives, etc., which are also used to store data. 2.5 Basic Anatomy of Computer: Anatomy of digital computer is basically related to the fundamental functioning of the digital computer system.... A digital computer is a combination of certain vital components like hardware, software Central processing unit, Arithmetic, and logic unit, Memory, Registers, Microprocessor, and some addresses. 26  Fig. Anatomy of Computer 2.6 Applications of Computer Computers play a role in every field of life. They are used in homes, business, educational institutions, research organizations, medical field, government offices, entertainment, etc. Education Computers are used in education sector through online classes, online examinations, referring e-books, online tutoring, etc. They help in increased use of audio- visual aids in the education field. At Home. Computers are used at homes for several purposes like online bill payment, watching movies or shows at home, home tutoring, social media access, playing games, internet access, etc. They provide communication through electronic mail. They help to avail work from home facility for corporate employees. Computers help the student community to avail online educational support. Business and Marketing Nowadays, computers are totally integrated into business. The main objective of business is transaction 27 processing, which involves transactions with suppliers, employees or customers. Computers can make these transactions easy and accurate. People can analyze investments, sales, expenses, markets and other aspects of business using computers. Banking Sector In the banking sector, computers are used to store details of customers and conduct transactions, such as withdrawal and deposit of money through ATMs. Banks have reduced manual errors and expenses to a great extent through extensive use of computers. Entertainment Computers help to watch movies online, play games online; act as a virtual entertainer in playing games, listening to music, etc. MIDI instruments greatly help people in the entertainment industry in recording music with artificial instruments. Videos can be fed from computers to full screen televisions. Photo editors are available with fabulous features. Medical Hospital Computers are used in hospitals to maintain a -rays, live monitoring of patients, etc. Surgeons nowadays use robotic surgical devices to perform delicate operations, and conduct surgeries remotely. Virtual reality technologies are also used for training purposes. It also helps to monitor the fetus inside Science and Research and Government Computers with high performance are used to stimulate dynamic process in Science and Engineering. Supercomputers have numerous applications in area of 28  Research and Development (R&D). Topographic images can be created through computers. Scientists use computers to plot and analyze data to have a better understanding of earthquakes. In government sectors, computers are used in data processing, maintaining a database of citizens and organizations have greatly benefitted from computers in their use for missile development, satellites, rocket launches, etc., 2.7 COMPUTER MEMORY AND ITS TYPES The computer memory holds the data and instructions needed to process raw data and produce output. The computer memory is divided into large number of small parts known as cells. Each cell has a unique address which varies from 0 to memory size minus one. Computer memory is of two types: Volatile (RAM) and Non-volatile (ROM). The secondary memory (hard disk) is referred as storage not memory. Fig. Memory types But, if we categorize memory on behalf of space or location, it is of four types: Primary memory 29  Secondary memory Register memory Cache memory Primary Memory Primary memory, often called main memory, constitutes that device, or group of devices, that holds instructions and data for rapid and direct access by the computer's central processing unit (CPU). Primary memory is synonymous with random-access memory (RAM). Primary Memory is of two types: RAM and ROM. Random Access Memory RAM (Volatile Memory) It is a volatile memory. It means it does not store data or instructions permanently. When you switch on the computer the data and instructions from the hard disk are stored in RAM. CPU utilizes this data to perform the required tasks. As soon as you shut down the computer the RAM loses all the data. Read Only Memory ROM (Non-volatile Memory) It is a non-volatile memory. It means it does not lose its data or programs that are written on it at the time of manufacture. So it is a permanent memory that contains all important data and instructions needed to perform important tasks like the boot process. SECONDARY MEMORY Secondary memory storage is generally a storage medium for noncritical data that does not need to be frequently accessed. It is initially referred to the class of media that is used to store the data. While secondary storage on the one hand does not need to be accessed as frequently as primary data, but its recovery of can prove crucial while replacing the information and applications that a 30 business need. With the increase in corporate data growth, storage managers are also adopting more secondary storage in order to reclaim capacity on primary storage arrays. The ability to maintain older data copies in an easily accessible form that satisfies business and also meets all regulatory compliance requirements. Secondary storage devices are rated on the basis of: Performance Data migration Speed Cloud service provider Volume manager The secondary storage devices which are built into the computer or connected to the computer are known as a secondary memory of the computer. It is also known as external memory or auxiliary storage. It is accessed indirectly via input/output operations. It is non- volatile, so permanently stores the data even when the computer is turned off or until this data is overwritten or deleted. The CPU can't directly access the secondary memory. First, the secondary memory data is transferred to primary memory then the CPU can access it. It is also called auxiliary memory or mass storage, consists of devices not directly accessible by the CPU. Hard drives, floppy disks, tapes, and optical disks are widely used for secondary storage. First, most secondary storage devices are capable of containing much more information than is feasible for primary memory (hence the use of the term "mass storage" as a synonym for secondary memory). A second, and essential, feature of secondary memory is that it is non-volatile. This means that data is stored with or without electrical power being supplied to the device, as opposed to RAM, which can retain its data only so long as electrical power is present. 31  Like primary memory, many secondary memory devices are capable of storing information, as well as retrieving it. Magnetic technology devices (such as hard drives, floppy disks, and tape) have this read-write capability, as do magnetooptical drives. However, some mass storage devices can only read data, as in the case of CD- ROM (Compact Disk-Read Only Memory) drives. CD-ROMs utilize optical technology; however, newer optical technologies, such as CD-RW (compact disk-rewriteable), can both read and write information like magnetic storage devices. The hard disk is the main, and usually largest, data storage device in a computer. The operating system, software titles and most other files are stored in the hard disk. MAGNETIC DISK Magnetic disks are circular metal plates coated with a magnetized material on both sides. Several disks are stacked on a spindle one below the other with read/ write heads to make a disk pack. The disk drive consists of a motor and all the disks rotate together at very high speed. Information is stored on the surface of a disk along a concentric set of rings called tracks. These tracks are divided into sections called sectors. A cylinder is a pair of corresponding tracks in every surface of a disk pack. Disk drives are connected to a disk controller. Thus, if a disk pack has n plates, there will be 2n surfaces; hence, the number of tracks per cylinder is 2n. The minimum quantity of information which can be stored, is a sector. If the number of bytes to be stored in a sector is less than the capacity of the sector, the rest of the sector is padded with the last type recorded. The following figure shows a magnetic disk memory. 32  Fig. Magnetic Disk Memory FLOPPY DISK A floppy disk, also known as a diskette, is a very convenient bulk storage device and can be taken out of the computer. It is of 5.25" or 3.5" size, the latter size being more common. It is contained in a rigid plastic case. The read/write hea ds of the disk drive can write or read information from both sides of the disk. The storage of data is in magnetic form, similar to that of the hard disk. The 3.5" floppy disk has a capacity of storage up to 1.44 Mbytes. It has a hole in the centre for mounting it on the drive. Data on the floppy disk is organized during the formatting process. The disk is also organized into sectors and tracks. The 3.5" high density disk has 80 concentric circles called tracks and each track is divided into 18 sectors. Tracks and circles exist on both sides of the disk. Each sector can hold 512 bytes of data plus other information like address, etc. It is a cheap read/write bulk storage device. 33  Fig. Floppy Disk MAGNETIC TAPE A magnetic disk is used by almost all computer systems as a permanent storage device. It is still the accepted low-cost magnetic storage medium, and is primarily used for backup storage purposes. The digital audio tape (DAT) is the normal backup magnetic tape tool used these days. A standard cartridge-size cassette tape offers about 1.2 GB of storage. These magnetic tape memories are similar to that of audio tape recorders. Fig. Magnetic Tape A magnetic tape drive consists of two spools on which the tape is wound. Between the two spools, there is a set of nine magnetic heads to write and read information on the tape. The nine 34 heads operate independently and record information on nine parallel tracks, all parallel to the edge of the tape. Eight tracks are used to record a byte of data and the ninth track is used to record a parity bit for each byte. The standard width of the tape is half an inch. The number of bits per inch (bpi) is known as recording density. Normally, when data is recorded on to a tape, a block of data is recorded and then a gap is left and then another block is recorded, and so on. This gap is known as Inter-Block Gap (IBG). The blocks are normally 10 times as long as IBG. The Beginning Of the Tape (BOT) is indicated through a metal foil known as marker, and the end of the tape (EOT) is also indicated through a metal foil known as end of tape marker. The data on the tape is arranged as blocks and cannot be addressed. It can only be retrieved sequentially in the same order in which it is written. Thus, if a desired record is at the end of the tape, earlier records have to be read before it is reached and hence the access time is very high as compared to magnetic disks. Optical Disk This (optical disk) storage technology has the benefit of high-volume economical storage coupled with slower times than magnetic disk storage. Compact Disk-Read Only Memory (CD-ROM) The CD-ROM optical drives are employed for storage of data that is circulated for read-only use. A single CD-ROM has the capacity to hold around 800 MB of data. This media can be used when software and huge reports are to be circulated to a large number of users. As compared to floppy disks or tapes, CD-ROM is more dependable for circulation. Nowadays, almost all software and documentations are circulated only on CD-ROM. 35  In a CD-ROM, data is stored uniformly across the disk in parts made of equal size. So, as you go towards the outer surface of the disk, the data stored on a track increases. Thus, CD-ROMs are rotated at changing speeds for reading. Fig. CD-ROM Information in a CD-ROM is written by creating pits on the disk surface by shining a laser beam. As the disk rotates, the laser beam traces out a continuous spiral. When 1 is to be written on the disk, a circular pit of around 0.8-micrometer diameter is created by the sharply focussed beam and no pit is created if a zero is to be written. The pre-recorded information on a CD-ROM is read with the help of a CD-ROM reader, which uses a laser beam for reading. For this, the CD- ROM disk is inserted into a slot of CD drive. Then, a motor rotates the disk. A laser head moves in and out of the specified position. As the disk rotates, the head senses pits and converted to 1s and 0s by the electronic interface and sent to the computer. The following figure depicts a CD-ROM. 36  The speed of the disk is indicated by nx, where n is an integer indicating the factor by which the original nominal speed of 150 KB/S is multiplied. Thus, a 52X CD-ROM disk speed will be 52 × 150 = 7800 KB/S. The CD-ROM has a buffer size of 256 Kilobytes to keep data temporarily. A Small Computer System Interface (SCSI) adapter connects it to the computer system. The following are the major benefits of CD-ROM: It has the capacity to store large amounts of data/information. Its mass replication is fast and inexpensive. It has removable disks. The following are the demerits of CD-ROM: It is read-only and hence cannot be updated. Access time is longer than that of a magnetic disk. Erasable Optical Disk A recent development in optical disk technology is the erasable optical disk. The erasable optical disk can be a substitute for the standard magnetic disk, subject to the condition that the speed of access is not essential and the quantity of data stored is large. The optical disk is used for multimedia, image and high-volume, low- activity backup storage. Data in these disks can be changed repeatedly as in a magnetic disk. The erasable optical disk is portable, 37 highly reliable and has a longer life. It uses a format that makes semi- random access feasible. Digital Versatile Disc (DVDs): A DVD is a type of optical media used for storing digital data. It is the same size as a CD, but has a larger storage capacity. Some DVDs are formatted specifically for video playback, while others may contain different types of data, such as software programs and computer files. DVDs can be divided into three main categories which are as follows: DVD-ROM (Read-Only): These types of DVDs come with media already recorded on them, such as movie dvds. As the name suggests, data on these discs cannot be erased or added, so these discs are known as a read-only or non-writable DVD. DVD-R (Writable): It allows you to record or write information to the DVD. However, you can write information only once as it becomes a read- only DVD once it is full. DVD-RW (Rewritable or Erasable): This type of discs can be erased, written, or recorded multiple times. Register Memory Register memory is the smallest and fastest memory in a computer. It is not a part of the main memory and is located in the CPU in the form of registers, which are the smallest data holding 38 elements. A register temporarily holds frequently used data, instructions, and memory address that are to be used by CPU. They hold instructions that are currently processed by the CPU. All data is required to pass through registers before it can be processed. So, they are used by CPU to process the data entered by the users. Registers hold a small amount of data around 32 bits to 64 bits. The speed of a CPU depends on the number and size (no. of bits) of registers that are built into the CPU. Registers can be of different types based on their uses. Some of the widely used Registers include Accumulator or AC, Data Register or DR, the Address Register or AR, Program Counter (PC), I/O Address Register, and more. Computer Registers: Data Register: It is a 16-bit register, which is used to store operands (variables) to be operated by the processor. It temporarily stores data, which is being transmitted to or received from a peripheral device. Program Counter (PC): It holds the address of the memory location of the next instruction, which is to be fetched after the current instruction is completed. So, it is used to maintain the path of execution of the different programs and thus executes the programs one by one, when the previous instruction gets completed. Instructor Register: It is a 16-bit register. It stores the instruction which is fetched from the main memory. So, it is used to hold instruction codes, 39 which are to be executed. The Control Unit takes instruction from Instructor Register, then decodes and executes it. Accumulator Register: It is a 16-bit register, which is used to store the results produced by the system. For example, the results generated by CPU after the processing are stored in the AC register. Address Register: It is a 12-bit register that stores the address of a memory location where instructions or data is stored in the memory. I/O Address Register: Its job is to specify the address of a particular I/O device. I/O Buffer Register: Its job is to exchange the data between an I/O module and the CPU. Cache Memory: Cache memory is a high-speed memory, which is small in size but faster than the main memory (RAM). The CPU can access it more quickly than the primary memory. So, it is used to synchronize with high-speed CPU and to improve its performance. Cache memory can only be accessed by CPU. It can be a reserved part of the main memory or a storage device outside the CPU. It holds the data and programs which are frequently used by the CPU. So, it makes sure that the data is instantly available for CPU whenever the CPU needs this data. In other words, if the CPU 40 finds the required data or instructions in the cache memory, it doesn't need to access the primary memory (RAM). Thus, by acting as a buffer between RAM and CPU, it speeds up the system performance. Types of Cache Memory: L1: It is the first level of cache memory, which is called Level 1 cache or L1 cache. In this type of cache memory, a small amount of memory is present inside the CPU itself. If a CPU has four cores (quad core cpu), then each core will have its own level 1 cache. As this memory is present in the CPU, it can work at the same speed as of the CPU. The size of this memory ranges from 2KB to 64 KB. The L1 cache further has two types of caches: Instruction cache, which stores instructions required by the CPU, and the data cache that stores the data required by the CPU. L2: This cache is known as Level 2 cache or L2 cache. This level 2 cache may be inside the CPU or outside the CPU. All the cores of a CPU can have their own separate level 2 cache, or they can share one L2 cache among themselves. In case it is outside the CPU, it is connected with the CPU with a very high-speed bus. The memory size of this cache is in the range of 256 KB to the 512 KB. In terms of speed, they are slower than the L1 cache. L3: It is known as Level 3 cache or L3 cache. This cache is not present in all the processors; some high-end processors may have this type of cache. This cache is used to enhance the performance of Level 1 and Level 2 cache. It is located outside the CPU and is shared by all the cores of a CPU. Its memory size ranges from 1 MB to 8 MB. Although it is slower than L1 and L2 cache, it is faster than Random Access Memory (RAM). 41 Memory Units Memory units are used to measure and represent data. Some of the commonly used memory units are: 1) Bit: The computer memory units start from bit. A bit is the smallest memory unit to measure data stored in main memory and storage devices? A bit can have only one binary value out of 0 and 1. 2) Byte: It is the fundamental unit to measure data. It contains 8 bits or is equal to 8 bits. Thus a byte can represent 2*8 or 256 values. 3) Kilobyte: A kilobyte contains 1024 bytes. 4) Megabyte: A megabyte contains 1024 kilobytes. 5) Gigabyte: A gigabyte contains 1024 megabyte. 6) Terabyte: A terabyte contains 1024 gigabytes. Books for Reference: 1. Dennis P.Curtin, Kim dolwy, KunL AWN, Xrhleen morin, Information Technology, the breaking wave, TMH 2000. 2. Stacey C Sawyer, Brain K Williams, Sarah E Hutchinson Using Information Technology Brief Version A Practical Introduction to Computer and Communications Third Edition, McGraw Hill Companies 2011. 3. Introduction to Information systems. 16th edition, 2005. ***** 42  UNIT III SOFTWARE FUNDAMENTALS Structure 3.1Software - Introduction 3.2 Kinds of Software 3.3 Applications software and its types 3.3.1 Word processing 3.3.2 Spreadsheets 3.3.3 Database software 3.3.4 Presentation graphics software 3.3.5 Communication software 3.4 System Software 3.4.1 Operating system 3.4.1.1 functions 3.1 SOFTWARE A computer cannot operate without any instructions and is based on a logical sequence of instructions in order to perform a constitute the computer software. The sequences of instructions are based on algorithms that provide the computer with instructions on how to perform a function. Thus, it is impossible for a computer to process without software, a term attributed to John W. Tukey in 1958. Different kinds of software designs have been developed for particular functions. Popular computer software include interpreter, assembler, compiler, operating systems, networking, word processing, accounting, presentation, graphics, computer games, etc. The computer software is responsible for converting the instructions in a program into a machine language facilitating their execution. 43  Software is a set of programs, which is designed to perform a well-defined function. A program is a sequence of instructions written to solve a particular problem. 3.2 KINDS OF SOFTWARE: Today, software is a significant aspect of almost all fields including business, education, medicine, etc. The basic requirement for software is a distinct set of procedures. Thus, software can be used in any domain that can be described in logical and related steps and every software is developed with the aim of catering to a particular objective, such as data processing, information sharing, communication, etc. Software is based on the type of applications that are as follows: System Software: This type of software is involved managing and controlling the operations of a computer system. System software is a group of programs rather than one program and is responsible for using computer resources efficiently and effectively. Operating system, for example, is system software, which controls the hardware, manages memory and multitasking functions and acts as an interface between applications programs and the computer. Real-Time Software: This is based on observing, analysing and controlling real life events as they occur. Manually, a real-time system guarantees a response to an external event within a specified period of time. The real- time software, for instance, is used for navigation in which the computer must react to a steady flow of new information without interruption. Most defence organizations all over the world use real time software to control their military hardware. 44 Business Software: This kind of software is functional in the domain of management and finance. The basic aspect of a business system comprises payroll, inventory, accounting and software that permits users to access relevant data from the database. These activities are usually performed with the help of specialized business software that facilitates efficient framework in the business operation and in management decisions. Engineering and Scientific Software: This software has developed as a significant tool used in the research and development of next generation technology. Applications, such as study of celestial bodies, study of under surface activities and programming of orbital path for space shuttle, are heavily dependent on engineering and scientific software. This software is designed to perform precise calculations on complex numerical data that are obtained during real-time environment. Artificial Intelligence (AI) Software: Certain problem solving techniques are non-algorithmic in nature and primarily require this type of software. The solutions to such problems normally cannot be arrived at using computation or straightforward analysis. Such problems need particular problem solving techniques including expert system, pattern recognition and game playing. Also, it constitutes various kinds of searching techniques, such as the application of heuristics. The function of AI is to add certain degree of intelligence into the mechanical hardware to have the desired work done in an agile manner. Web Based Software: 45  This category of software performs the function of an interface between the user and the Internet. There are various forms in which data is available online, such as text, audio or video format, linked with hyperlinks. For the retrieval of Web pages from the Internet a Web browser is used, which is a Web based software. The software incorporates executable instructions written in special scripting languages, such as Common Gateway Interface (CGI) or Active Server Page (ASP). Apart from providing navigation on the Web, this software also supports additional features that are useful while surfing the Internet. Personal Computer (PC) Software: This software is primarily designed for personal use on a daily basis. The past few years have seen a marked increase in the personal computer software market from normal text editor to word processor and from simple paintbrush to advance image editing software. This software is used mostly in almost every field, whether it is database management system, financial accounting package or a multimedia based software. It has emerged as a versatile tool for daily life applications. Software can also be classified in terms of the relationship between software users or software purchasers and software development. Commercial Off-The-Shelf (COTS): This comprises the software without any committed user before it is put up for sale. The software users have less or no contact with the vendor during development. It is sold through retail stores or distributed electronically. This software includes commonly used programs, such as word processors, spreadsheets, games, income tax 46 programs, as well as software development tools, such as software testing tools and object modelling tools. Customized or Bespoke: This software is designed for a specific user, who is bound by some kind of formal contract. Software developed for an aircraft, for example, is usually done for a particular aircraft making -the- processing software. Customized COTS: In this classification, a user can enter into a contract with the software vendor to develop a COTS product for a special purpose, that is, software can be customized according to the needs of the user. Another growing trend is the development of COTS software components the components that are purchased and used to develop new applications. The COTS software component vendors are essentially parts stores which are classified according to their application types. These types are listed as follows: Stand-Alone Software: A software that resides on a single computer and does not interact with any other software installed in a different computer. Embedded Software: A software that pertains to the part of unique application involving hardware like automobile controller. Real-Time Software: In this type of software the Operations are executed within very short time limits, often microseconds, e.g., radar software in air traffic control system. 47  Network Software: In this type of software, software and its components interact across a network. On the functional basis, software is categorized as follows: 3.2.1 Application Software: o It helps the end users to complete one or more specific tasks. The specific applications include industrial automation, business software, computer games, telecommunications, databases, educational software, medical software and military software. 3.2.2 System Software: o It helps in the proper functioning of computer hardware. It includes device drivers, operating systems, servers and utilities. 3.3 APPLICATION SOFTWARE AND ITS TYPES Application software is a set of programs designed to perform a specific task. It does not control the working of a computer as it is designed for end-users. A computer can run without application software. Application software can be easily installed or uninstalled as required. It can be a single program or a collection of small programs. Users install specific software programs based on their requirements; for instance, accounting software (like Tally) used in business organizations and designing software used by architects. All programs, languages and utility programs constitute software. With the help of these programs, users can design their own software based on individual preferences. Software programs aid in achieving efficient application of computer hardware and other resources. Licensed Software 48  Although there is a large availability of open source or free software online, not all software available in the market is free for use. Some software falls under the category of Commercial Off-The- Shelf (COTS). COTS is a term used for software and hardware technology which is available to the general public for sale, license or lease. In other words, to use COTS software, you must pay its developer in one way or another. Most of the application software available in the market need a software license for use. Software is licensed in different categories. Some of these licenses are based on the number of unique users of the software while other licenses are based on the number of computers on which the software can be installed. A specific distinction between licenses would be an Organizational Software License, which grants an organization the right to distribute the software or application to a certain number of users or computers within the organization, and a Personal Software License which allows the purchaser of the application to use the software on his or her computer only. Free Domain Software To understand this, let us distinguish between the commonly used terms Freeware and Free Domain software. T has no clear accepted definition, but is commonly used for packages that permit redistribution but not modification. This means that their source code is not available. Free domain software is software that comes with permission for anyone to use, copy, and distribute, either verbatim or with modifications, either gratis or for a fee. In particular, this means that the source code must be available. Free domain software can be freely used, modified, and redistributed but with one restriction: the redistributed software must be distributed with the original terms of free use, modification and distribution. This is 49 Free software may be packaged and distributed for a fee. T here refers to the ability of reusing it modified or unmodified, as a part of another software package. The concept of free software is the brainchild of Richard Stallman, head of the GNU project. The best known example of free software is Linux, an operating system that is proposed as an alternative to Windows or other proprietary operating systems. Types of Application Software Word Processing Spread Sheet Presentation Database Multimedia 3.3.1 WORD PROCESSING Microsoft Word is a word processing computer application program written by Microsoft. It is mainly used to design text for presentation. It helps in arranging written text in a proper format and giving it a systematic look. This formatted look facilitates easier reading. It is an application program used for the production of any type of printable text document including composition, editing, formatting and printing. It takes the advantage of a Graphical User Interface (GUI) to present data in a required format. It can produce any arbitrary combination of images, graphics and text. Microsoft Word is the most widely used word processing system. It can be used for the simplest to the most complex word processing applications. Using Word, you can write letters and reports, prepare bills and invoices, prepare office stationery, such as 50 letterheads, envelopes and forms, design brochures, pamphlets, newsletters and magazines, etc This software allows users to create, edit, format, and manipulate the text and more. It offers lots of options for writing documents, creating images, and more. For example, MS Word, WordPad, Notepad, etc. It includes all topics of MS Word such as save the document, correct error, word count, font size, font style, apply a style, customize a style, page size, page margin, insert header and footer and more. It provides spell-check options, formatting functions like cut-copy-paste, and spots grammatical errors on a real-time basis. It also helps in saving and storing documents. Fig. Microsoft Word Document before printing it; organize the data into lists and then summarize, compare and present the data graphically. It allows the header and footer to display descriptive information, and to produce personalized letters through mail. This software is used to create, format and edit any document. It allows us to share the resources such as clip arts, drawing tools, etc. available to all office programs. 51 3.3.2 SPREAD SHEET: MS EXCEL Excel is and spread Sheet application ideal for a task that needs a number of lists, tables, financial calculations, analysis and graphs. Excel is good for organizing different kinds of data, however it is numerical data that is best suited. Thus, Excel can be used when you not only need a tool for storing and managing data, but also analysing and querying it. In addition to providing simple database capabilities, Excel also allows you to create documents for the World Wide Web (WWW). The menus, toolbars and icons of MS Excel are very similar (though not the same) to MS Word. This is in keeping with this means less time spent in learning the second package once you know the first, and almost effortless and seamless exchange of data between various components. Fig. Microsoft Excel Worksheet Spreadsheet software is used to perform calculations. In this software, data is stored in a table format. The intersecting area, called cells, are separated to define fields such as text, date, time, 52 and number. It allows users to provide formulas and functions to perform calculations. Microsoft Excel is one good example of spreadsheet software. It is one of the most suitable spreadsheet functions that help us manage data, create optically logical charts, and thought- provoking graphs. Microsoft Excel is supported by both Mac and PC platforms. Microsoft Excel can also be used to balance a check book, create an expense document, build formulas, and edit them. It mainly comprises tabs, groups of commands, and worksheets. The worksheet is made of rows and columns that intersect each other to form cells where data is entered. It is capable of performing multiple tasks like calculations, data analysis, and integrating data. Microsoft Office button, ribbon, and quick access toolbar are the three main features of excel that you need to focus on while learning excel. Microsoft Excel Features There are several features that are available in Excel to make our task more manageable. Some of the main features are; 53 Excel Interface After starting Excel, we will see two windows - one within the other. The outer window is the Application Window, and the inner window is a Workbook Window. When maximized, the Excel Workbook Window composite in with the Application Window. After completing this module, we should be able to: Identify the components of the Application Window. Identify the components of the Workbook Window. 3.3.3 PRESENTATION GRAPHIC SOFTWARE MSPOWER POINT Some very popular presentation software, such as Microsoft's Power point and Lotus's Freelance Graphics, are sold stand-alone or can come as part of office-oriented suites or packages of software. Other popular products include Adobe Persuasion, Astound, Asymetrix Compel, Corel Presentations, and Harvard Graphics. Among the most popular multimedia authoring tools are Macromedia Director and Asymetrix's Multimedia Toolbook. These authoring tools also 54 include presentation capability as well. Most if not all of these products come in both PC and Mac versions. Fig. Microsoft Power Point Recently, a new presentation tool has arrived: your Web browser and the tools for creating Web pages, such as Microsoft's FrontPage and Adobe's PageMill. The ubiquity of these tools and the browser as a playback device make this a popular approach, especially when a presentation can combine HTML pages on the hard disk with links to outside sites (if you have a live Internet connection). Fig. Windows Media Player 55  Multimedia software are developed to perform editing of video, audio, and text. It allows you to combine texts, videos, audio, and images. Thus, you can improve a tex t document by adding photos, animations, graphics, and charts through multimedia software. For example, VLC player, Window Media Player, etc. 3.3.4 DATABASE SOFTWARE: MS ACCESS Database software is used to create and manage a database. Also known as a DBMS (Database Management System), it helps you organize your data. So, when you run an application, data is fetched from the database, modified, and is stored back in the database. Oracle, MySQL, Microsoft SQL Server, PostgreSQL, MongoDB, and IBM Db2 are some popular databases. 3.3.5 COMMUNICATION SOFTWARE Communication software is an application or program designed to pass information from one system to another. Such software provides remote access to systems and transmits files in a multitude of formats between computers. Communication software forms a part of communication systems with software components classified according to functions within the Open Systems Interconnection Model (OSI Model). The best-defined examples of communication software are file transfer protocol (FTP), messaging software and email. 3.4 SYSTEM SOFTWARE System software is software designed to provide a platform for other software. Examples of system software include operating systems like macOS, GNU/Linux , Android and Microsoft Windows, 56 computational science software, game engines, industrial automation, and software as a service applications. System software constitutes all the programs, languages and documentation provided by the manufacturer in the computer. These programs provide the user with an access to the system so that he can communicate with the computer and write or develop his own programs. The software makes the machine user-friendly and makes an efficient use of the resources of the hardware. Systems software are permanent programs on a system and reduce the burden of the programmer as well as aid in maximum resource utilization. MS DOS (Microsoft Disk Operating System) was one of the most widely used systems software for IBM compatible microcomputers. Windows and its different versions are popular examples of systems software. Systems software are installed permanently on a computer system used on a daily basis. The system software is a collection of programs designed to operate, control, and extend the processing capabilities of the computer itself. System software is generally prepared by the computer manufacturers. These software products comprise of programs written in low-level languages, which interact with the hardware at a very basic level. System software serves as the interface between the hardware and the end users. Some examples of system software are Operating System, Compilers, Interpreter, Assemblers, etc. Some other examples of system software include: BIOS: It stands for basic input output system. It is a type of system software, which is stored in Read Only Memory (ROM) located on the motherboard. However, in advanced computer systems, it is stored in flash memory. BIOS is the first software that gets activated 57 when you turn on your computer system. It loads the drivers of the hard disk into memory as well as assists the operating system to load itself into the memory. Boot Program: Boot refers to starting up a computer. When you switch on the computer, the commands in the ROM are executed automatically to load the boot program into memory and execute its instructions. The BIOS program has a basic set of commands that enables the computer to perform the basic input/output instructions to start the computer. An assembler: It plays the role of a converter as it receives basic computer instructions and converts them into a pattern of bits. The processor uses these bits to perform basic operations. A device driver: This system software controls hardware devices connected to a computer. It enables the computer to use the hardware by providing an appropriate interface. The kernel of a Computer's CPU communicates with different hardware through this software. Operating systems generally come with most of the device drivers. If the operating system does not have a device driver for hardware, you have to install the device driver before using that hardware device. 3.4.1 Operating systems The computer's OS is a well-known example of system software. Widely used operating systems include Microsoft Windows, macOS and Linux. Unlike other system software types, the average computer user regularly interacts with the computer OS 58 through its graphical UI (GUI) and, with some operating systems, a less complex command-line interface (CLI).Because a GUI is a program that sits on top of the OS, it may be referred to as application software, not system software. In other words, the GUI is application software that makes it possible for the user to manipulate parts of the OS. 3.4.1.1 Functions of an operating System 1. Security The operating system uses password protection to protect user data and similar other techniques. it also prevents unauthorized access to programs and user data. 2. Control over system performance Monitors overall system health to help improve performance. records the response time between service requests and system response to have a complete view of the system health. This can help improve performance by providing important information needed to troubleshoot problems. 3. Job accounting Operating system Keeps track of time and resources used by various tasks and users, this information can be used to track resource usage for a particular user or group of user. 4. Error detecting aids Operating system constantly monitors the system to detect errors and avoid the malfunctioning of computer system. 5. Coordination between other software and users Operating systems also coordinate and assign interpreters, compilers, assemblers and other software to the various users of the computer systems. 6. Memory Management 59  The operating system manages the Primary Memory or Main Memory. Main memory is made up of a large array of bytes or words where each byte or word is assigned a certain address. Main memory is a fast storage and it can be accessed directly by the CPU. For a program to be executed, it should be first loaded in the main memory. An Operating System performs the following activities for memory management: It keeps tracks of primary memory, i.e., which bytes of memory are used by which user program. The memory addresses that have already been allocated and the memory addresses of the memory that has not yet been used. In multi programming, the OS decides the order in which process are granted access to memory, and for how long. It Allocates the memory to a process when the process requests it and deallocates the memory when the process has terminated or is performing an I/O operation. 7. Processor Management In a multi programming environment, the OS decides the order in which processes have access to the processor, and how much processing time each process has. This function of OS is called process scheduling. An Operating System performs the following activities for processor management. Keeps tracks of the status of processes. The program which perform this task is known as traffic controller. Allocates the CPU that is processor to a process. De-allocates processor when a process is no more required. 8. Device Management An OS manages device communication via their respective drivers. It performs the following activities for device management. Keeps tracks of all devices connected to system. designates a program responsible for every device known as the 60  Input/Output controller. Decides which process gets access to a certain device and for how long. Allocates devices in an effective and efficient way. Deallocates devices when they are no longer required. 9. File Management A file system is organized into directories for efficient or easy navigation and usage. These directories may contain other directories and other files. An Operating System carries out the following file management activities. It keeps track of where information is stored, user access settings and status of every file system. Summary A computer cannot operate without any instructions and is based on a logical sequence of instructions in order to perform a function. Different kinds of software designs have been developed for particular functions. Popular computer software include interpreter, assembler, compiler, operating systems, networking, word processing, accounting, presentation, graphics, computer games, etc. Today, software is a significant aspect of almost all fields including business, education, medicine, etc. Web based software performs the function of an interface between the user and the Internet. Engineering and scientific software has developed as a significant tool used in the research and development of next generation technology. 61  System software constitutes all the programs, languages and documentation provided by the manufacturer in the computer. The software makes the machine user-friendly and makes an efficient use of the resources of the hardware. Windows and its different versions are popular examples of systems software. An Operating System (OS) is the main control program for handling all other programs in a computer. The role of an OS in a computer is similar to the role of the manager in an office for the overall management of the college. A linkage editor is an editor program that establishes a single module from many modules by resolving cross references among the modules. Users install specific software programs based on their requirements; for instance, accounting software (like Tally) used in business organizations and designing software used by architects. A word processor is an application program used for the production of any type of printable text document including composition, editing, formatting and printing. Excel is ideal for a task that needs a number of lists, tables, financial calculations, analysis and graphs. Books for Reference: 1. Dennis P.Curtin, Kim dolwy, KunL AWN, Xrhleen morin, Information Technology, the breaking wave, TMH 2000. 2. Stacey C Sawyer, Brain K Williams, Sarah E Hutchinson Using Information Technology Brief Version A Practical Introduction to Computer and Communications Third Edition, McGraw Hill Companies 2011. 62  UNIT IV COMPUTER NETWORKS Structure 4.1 Introduction 4.2 Definition of Computer Networks 4.3 Types of Computer Networks 4.3.1 Local Area Network (LAN) 4.3.2 Metropolitan Area Networks (MAN) 4.3.3 Wide Area Network (WAN) 4.3.4 Personal Area Network (PAN) 4.4 Internet 4.5 Intranet 4.6 Firewalls 4.7 Network Topology 4.7.1 Bus Topology 4.7.2 Ring Topology 4.7.3 Hybrid Topology 4.7.4 Star Topology 4.1 Introduction Network is used to share information and resources. Group of computer and their peripheral are connected with each other to share information and resources is called networking. Computers are connected to communicate. 4.2 Definition of Computer Networks A computer network is a system in which multiple computers are connected to each other to share information and resources. There are some major types of network i.e. LAN (Local Area Network), MAN (Metropolitan Area Network) and WAN 63 (Wide Area Network). Some other networks are also there which can be implemented like PAN (Personal Area Network), SAN (Storage Area Network), EPN (Enterprise Private Network), VPN (Virtual Private Network). These networks have some similarities and some dissimilarities. Major difference among these networks is their geographical area they cover. LAN is implemented in a small geographical area like within a building, office etc. MAN is spread within a city or town. WAN covers the largest area like Internet which is spread all over the world. These networks can be wired (with cables) or wireless (without cables). If we talk about the similarity then all the networks are used to share information and resources. This unit will deal with communication channels Advantages of a Computer Network: Share resources from one computer to another. Create files and store them in one computer, access those files from the other computer(s) connected over the network. Connect a printer, scanner, or a fax machine to one computer within the network and let other computers of the network use the machines available over the network. Following is the list of hardware's required to set up a computer network. Network Cables Distributors Routers Internal Network Cards External Network Cards 64 4.3 Computer Network Types A computer network is a group of computers linked to each other that enables the computer to communicate with another computer and share their resources, data, and applications. A computer network can be categorized by their size. Network is of different types: LAN (Local Area Network) MAN (Metropolitan Area Network ) WAN ( Wide Area Network) PAN (Personal Area Network) SAN (Storage Area Network) EPN (Enterprise Private Network) VPN (Virtual Private Network) LAN: is used in small areas like office, building or an organisation. It is network which is spread in local area. The main purpose of LAN is to share information and resources. MAN: is used to share information within a city or town to share information. MAN is commonly used for TV cable network. WAN: is used to share information with world. It is spread all over the world. Example of WAN are Internet, Intranet, Bank ATM etc. PAN: Personal Area Network is a network which enables communication between computer devices near a person. SAN: It is a block-based storage. It is a technology by which high- speed architecture connects with servers to their logical disk units (LUNs). ALUN is a range of blocks provisioned from a pool of shared storage and presented to the server as a logical disk. 65 EPN: It is used by a business enterprise to connect its various company sites (such as production sites, offices and shops) in order to share computer resources. VPN: It is a network technology that is used to create a safe and encrypted connection over a less secure network, such as the internet. 4.3.1 Local Area Network (LAN) LAN or Local Area Network connects network devices in such a way that personal computer and workstations can share data, tools and programs. The group of computers and devices are connected together by a switch, or hub. It has its own addressing scheme as defined by the TCP/IP protocol. Each node is having different address. This address is obtained by PC automatically while network configuration or can be given manually to each PC. These addresses are unique in relation to other computers on the local network. Routers are placed at LAN for connecting with larger WAN. Data transmission rate very fast as the number of computers linked are limited. LAN uses be high speed and relatively inexpensive hardware (Such as hubs, network adapters and Ethernet cables). LANs cover smaller geographical area (Size is limited to a few meters) and are privately owned. One can use it for an office building, home, hospital, schools, etc. LAN is easy to design and maintain. A Communication medium used for LAN has twisted pair cables and coaxial cables. It covers a short distance, and so the error and noise are minimized. 66  The speed of LAN is normally 100 or 1000 Mbps. Propagation delay is very short in a LAN. LAN can comprise of two to many computers connected with each other. Generally wired LAN is setup with twisted pair cable of cat 3 or cat 6.Wired LAN is sued for increased speed and security, but wireless connections can also implemented known as WLAN. LAN has less network congestion and fault tolerance is more. LAN requirement are: LAN card or Ethernet card or NIC (Network Interface Card) Networking cable (twisted pair cat 3 or cat 6) Hub and Switch RJ 45 connector WAP (Wireless Access Point ) for wireless LAN Advantages of Networking 1. Efficient use of storage media: Data storage can be done at central location for east sharing and reducing duplicate data. 2. Quickest Document delivery: Document can be transferred quickly in local area network. 67  3. Sharing of hardware resources: Network hardware can be shared to work cost efficiently. Network hardware like printer, scanner can be shared. 4. Reduce redundancy: Repetition of data is reduced in networking. Information can be accessed in networking from any node. 5. Promote Multiuser environment: LAN support multiuser environment like many user can work on same workbook in Excel which is shared. It allows the editing done by multiuser. 6. Network security in LAN can be achieved by user authentication by password and by giving right access like read only, read and write access. Points to Remember: o Local Area Network is a group of computers connected to each other in a small area such as building, office. o LAN is used for connecting two or more personal computers through a communication medium such as twisted pair, coaxial cable, etc. o It is less costly as it is built with inexpensive hardware such as hubs, network adapters, and ethernet cables. o The data is transferred at an extremely faster rate in Local Area Network. o Local Area Network provides higher security. 4.3.2 Metropolitan Area Networks (MAN) A Metropolitan Area Network (MAN) is a network that covers a larger geographic area by interconnecting a different LAN to form a larger network. Government agencies use MAN to connect to the 68 citizens and private industries. In MAN, various LANs are connected to each other through a telephone exchange line. The most widely used protocols in MAN are RS-232, Frame Relay, ATM, ISDN, OC-3, ADSL, etc. It has a higher range than Local Area Network (LAN). Uses of Metropolitan Area Network: o MAN is used in communication between the banks in a city. o It can be used in an Airline Reservation. o It can be used in a college within a city. o It can also be used for communication in the military. 4.3.3 Wide Area Network (WAN) A Wide Area Network is a network that extends over a large geographical area such as states or countries. A Wide Area Network is quite bigger network than the LAN. A Wide Area Network is not limited to a single location, but it spans over a large geographical area through a telephone line, fiber optic cable or satellite links. The internet is one of the biggest WAN in the world. A Wide Area 69 Network is widely used in the field of Business, government, and education. Examples of Wide Area Network: o Mobile Broadband: A 4G network is widely used across a region or country. o Last mile: A telecom company is used to provide the internet services to the customers in hundreds of cities by connecting their home with fiber. o Private network: A bank provides a private network that connects the 44 offices. This network is made by using the telephone leased line provided by the telecom company. Advantages of Wide Area Network: o Geographical area: A Wide Area Network provides a large geographical area. Suppose if the branch of our office is in a different city then we can connect with them through WAN. The internet provides a leased line through which we can connect with another branch. 70  o Centralized data: In case of WAN network, data is centralized. Therefore, we do not need to buy the emails, files or back up servers. o Get updated files: Software companies work on the live server. Therefore, the programmers get the updated files within seconds. o Exchange messages: In a WAN network, messages are transmitted fast. The web application like Facebook, Whatsapp, Skype allows you to communicate with friends. o Sharing of software and resources: In WAN network, we can share the software and other resources like a hard drive, RAM. o Global business: We can do the business over the internet globally. o High bandwidth: If we use the leased lines for our company then this gives the high bandwidth. The high bandwidth increases the data transfer rate which in turn increases the productivity of our company. Disadvantages of Wide Area Network: o Security issue: A WAN network has more security issues as compared to LAN and MAN network as all the technologies are combined together that creates the security problem. o Needs Firewall & antivirus software: The data is transferred on the internet which can be changed or hacked by the hackers, so the firewall needs to be used. Some people can inject the virus in our system so antivirus is needed to protect from such a virus. o High Setup cost: An installation cost of the WAN network is high as it involves the purchasing of routers, switches. 71  o Troubleshooting problems: It covers a large area so fixing the problem is difficult. 4.3.4 Personal Area Networks (PAN) Thomas Zimmerman was the first research scientist to bring the idea of the Personal Area Network. Personal Area Network is a network arranged within an individual person, typically within a range of 10 meters. It is used for connecting the computer devices of personal use is known as Personal Area Network. It covers an area of 30 feet. Personal computer devices that are used to develop the personal area network are the laptop, mobile phones, media player and play stations. There are two types of Personal Area Network namely o Wired Personal Area Network o Wireless Personal Area Network Wireless Personal Area Network: Wireless Personal Area Network is developed by simply using wireless technologies such as WiFi, Bluetooth. It is a low range network. Wired Personal Area Network: Wired Personal Area Network is created by using the USB. Examples of Personal Area Network; o Body Area Network: Body Area Network is a network that moves with a person. For example, a mobile network moves with a person. Suppose a person establishes a network connection and then creates a connection with another device to share the information. 72  o Offline Network: An offline network can be created inside the home, so it is also known as a home network. A home network is designed to integrate the devices such as printers, computer, television but they are not connected to the internet. o Small Home Office: It is used to connect a variety of devices to the internet and to a corporate network using a VPN 4.4 Internet Internet is a global communication system that links together thousands of individual networks. It allows exchange of information between two or more computers on a network. Thus, internet helps in transfer of messages through mail, chat, video & audio conference. 4.5 Intranet Intranets increase communication within an organization by allowing employees to easily access important information, links, applications and forms as well as databases that can provide company records. Security can also be increased within the intranet by establishing a database that maintains all of the usernames of people who are allowed access to the network. Uses of the intranet Potential uses of an intranet include: Streamlining everyday activities by making repeated tasks more feasible. Centralizing and managing important information and company data in a single database. 73  Making collaboration easier since information can be shared across the entire network. Providing personalized content to employees based on their role within the company. Improving internal communication by making employee directories, company news and organization charts readily available. Providing fast and easy access to information about company policies, benefits and updates. 4.6 Firewall A firewall is a network security device that monitors incoming and outgoing network traffic and permits or blocks data packets based on a set of security rules. Its purpose is to establish a barrier between your internal network and incoming traffic from external sources (such as the internet) in order to block malicious traffic like viruses and hackers. 4.7 Network Topology The configuration, or topology, of a network is key to determining its performance. Network topology is the way a network is arranged, including the physical or logical description of how links and nodes are set up to relate to each other. There are numerous ways a network can be arranged, all with different pros and cons, and some are more useful in certain circumstances than others. Admins have a range of options when it comes to choosing a network topology, and this decision must account for the size and scale of their business, its goals, and budget. Several tasks go into effective network topology management, 74 including configuration management, visual mapping, and general performance monitoring. The key is to understand your objectives and requirements to create and manage the network topology in the right way for your business. Network topology refers to how various nodes, devices, and connections on your network are physically or logically arranged in relation to each other. Think of your network as a city, and the topology as the road map. Just as there are many ways to arrange and maintain a city such as making sure the avenues and boulevards can facilitate passage between the parts of town getting the most traffic there are several ways to arrange a