UNIT –I : INFORMATION TECHNOLOGY AND COMPUTERS

What is data?

Data can be defined as a representation of facts, concepts or instructions in a formalized manner which should

be suitable for communication, interpretation, or processing by human or electronic machine.

Data is represented with the help of characters like alphabets (A-Z,a-z), digits (0-9) or special characters(+,-

,/,*,<,>,= etc.).

What is Information?

Information is organised or classified data which has some meaningful values for the receiver.

Information is the processed data on which decisions and actions are based.

For the decision to be meaningful, the processed data must qualify for the following characteristics

Timely - Information should be available when required.

Accuracy - Information should be accurate.

Completeness - Information should be complete.

What is Information technology?

Set of tools, processes, and methodologies (such as coding/programming, data

communications, data conversion, storage and retrieval, systems analysis anddesign, systems control)

and associated equipment employed to collect,process, and present information. In broad terms, IT also

includes office automation, multimedia, and telecommunications.

What does Computer System mean?

Computer is an electronic machine which processes raw data to give meaningful information. It accepts

information(in the form of digitalized data) and manipulates it for some result based on a program.

A computer system is a basic, complete and functional computer, including all the hardware and software

required to make it functional for any user.

A computer system allows users to input, manipulate and store data. Computer systems typically include a

computer, monitor, keyboard, mouse and other optional components. All of these components also can be

integrated into all-in-one units, such as laptop computers.

During the data processing stage, instruction sets, known as programs, are provided to let the system know

what to do with the entered system data. Without these programs, the computer would not know how to

process data that enters the system, and the data might be discarded. Known as a stored program computer,

this type of computer is the most common in use today. It is very flexible, as it can process any task by loading

a program from storage. Computer systems can work by themselves or access other devices that are external

or connected with other computer systems.

Characteristics of computer 1. SPEED : Computer is very fast calculating device. It can execute basic operations like subtraction, addition, multiplication and division at a few microseconds. It can move and copy data at a speed in the order of billion instruction per second.

2. ACCURACY : Computer always gives accurate results. The accuracy of Computer does not go down when they are used continuously for hours together. It always gives accurate results. 3. STORAGE CAPACITY : Computer have a very large storage capacity. A large volume of information can be stored in the memory of computer and information can be retrieved correctly when desired. 4. VERSATILITY : The working of computer with different types of data is known as versatility. That means computer can perform different types of job efficiently. Computer can works with different type of data and information such as visuals, text, graphics & video etc. So, versatility is a most important characteristic of computer. 5. DILLIGENCE : A Computer can work for long hours with the same accuracy and speed because it is free from problems of boredom or lack of concentration. 6. NO THOUGHTS : Computers have no thoughts because they are machine and they are devoid of emotions. They have no feelings. Since, computers have no thoughts and feelings so they can't make judgment based on thoughts and feelings.

Evolution of Computers

Evolution in computer terminology is a change in technology a computer is/was being used. Initially, the generation term was used to distinguish between varying hardware technologies. But nowadays, generation includes both hardware and software, which together make up an entire computer system. There are totally five computer generations known till date. Each generation has been discussed in detail along with their time period and characteristics. Here approximate dates against each generations have been mentioned which are normally accepted. Following are the main five generations of computers

First Generation The period of first generation was 1946-1959. The computers of first generation used vacuum tubes as the basic components for memory and circuitry for CPU (Central Processing Unit). These tubes, like electric bulbs, produced a lot of heat and were prone to frequent fusing of the installations, therefore, were very expensive and could be afforded only by very large organizations. In this generation mainly batch processing operating system were used. Punched cards, paper tape, and magnetic tape were used as input and output devices. The computers in this generation used machine code as programming language. The main features of first generation are: -portable Some computers of this generation were:

-701

-650

Second Generation

The period of second generation was 1959-1965. In this generation transistors were used that were cheaper, consumed less power, more compact in size, more reliable and faster than the first generation machines made of vacuum tubes. In this generation, magnetic cores were used as primary memory and magnetic tape and magnetic disks as secondary storage devices. In this generation assembly language and high-level programming languages like FORTRAN, COBOL were used. The computers used batch processing and multiprogramming operating system.

The main features of second generation are: Some computers of this generation were:

Third Generation

The period of third generation was 1965-1971. The computers of third generation used integrated circuits (IC's) in place of transistors. A single IC has many transistors, resistors and capacitors along with the associated circuitry. The IC was invented by Jack Kilby. This development made computers smaller in size, reliable and efficient. In this generation remote processing, time-sharing, multi-programming operating system were used. High-level languages (FORTRAN-II TO IV, COBOL, PASCAL PL/1, BASIC, ALGOL-68 etc.) were used during this generation.

The main features of third generation are: ed -level language Some computers of this generation were: -360 series -6000 series

-370/168 TDC-316

Fourth Generation

The period of fourth generation was 1971-1980. The computers of fourth generation used Very Large Scale Integrated (VLSI) circuits. VLSI circuits having about 5000 transistors and other circuit elements and their associated circuits on a single chip made it possible to have microcomputers of fourth generation. Fourth generation computers became more powerful, compact, reliable, and affordable. As a result, it gave rise to personal computer (PC) revolution. In this generation time sharing, real time, networks, distributed operating system were used. All the high-level languages like C, C++, DBASE etc. were used in this generation.

The main features of fourth generation are: ry small size Some computers of this generation were: - PDP 11 -1(Super Computer) -X-MP(Super Computer)

Fifth Generation The period of fifth generation is 1980-till date. In the fifth generation, the VLSI technology became ULSI (Ultra Large Scale Integration) technology, resulting in the production of microprocessor chips having ten million electronic components. This generation is based on parallel processing hardware and AI (Artificial Intelligence) software. AI is an emerging branch in computer science, which interprets means and method of making computers think like human beings. All the high-level languages like C and C++, Java, .Net etc. are used in this generation.

AI includes: The main features of fifth generation are: - Development of true artificial intelligence

Some computer types of this generation are:

Classification of computers Computers can be broadly classified by their speed and computing power. Sr. No.

Type Specifications

1 PC (Personal Computer)

It is a single user computer system having moderately powerful microprocessor

2 WorkStation It is also a single user computer system which is similar to personal computer but have more powerful microprocessor.

3 Mini Computer It is a multi-user computer system which is capable of supporting hundreds of users simultaneously.

4 Main Frame It is a multi-user computer system which is capable of supporting hundreds of users simultaneously. Software technology is different from minicomputer.

5 Supercomputer It is an extremely fast computer which can execute hundreds of millions of instructions per second.

PC (Personal Computer)

A PC can be defined as a small, relatively inexpensive computer designed for an individual user. PCs are based on the microprocessor technology that enables manufacturers to put an entire CPU on one chip. Businesses use personal computers for word processing, accounting, desktop publishing, and for running spreadsheet and database management applications. At home, the most popular use for personal computers is playing games and surfing Internet. Although personal computers are designed as single-user systems, these systems are normally linked together to form a network. In terms of power, now-a-days High-end models of the Macintosh and PC offer the same computing power and graphics capability as low-end workstations by Sun Microsystems, Hewlett-Packard, and Dell.

Workstations

Workstation is a computer used for engineering applications (CAD/CAM), desktop publishing, software development, and other such types of applications which require a moderate amount of computing power and relatively high quality graphics capabilities. Workstations generally come with a large, high-resolution graphics screen, large amount of RAM, inbuilt network support, and a graphical user interface. Most workstations also have a mass storage device such as a disk drive, but a special type of workstation, called a diskless workstation, comes without a disk drive. Common operating systems for workstations are UNIX and Windows NT. Like PC, Workstations are also single-user computers like PC but are typically linked together to form a local-area network, although they can also be used as stand-alone systems.

Minicomputer It is a midsize multi-processing system capable of supporting up to 250 users simultaneously.

Mainframe Mainframe is very large in size and is an expensive computer capable of supporting hundreds or even thousands of users simultaneously. Mainframe executes many programs concurrently and supports many simultaneous execution of programs.

Supercomputer Supercomputers are one of the fastest computers currently available. Supercomputers are very expensive and are employed for specialized applications that require immense amount of mathematical calculations (number crunching). For example, weather forecasting, scientific simulations, (animated) graphics, fluid dynamic calculations, nuclear energy research, electronic design, and analysis of geological data (e.g. in petrochemical prospecting).

Applications of computers Following list demonstrates various applications of computers in today's arena.

Business

A computer has high speed of calculation, diligence, accuracy, reliability, or versatility which made it an integrated part in all business organisations. Computer is used in business organisations for:

Banking Today banking is almost totally dependent on computer. Banks provide following facilities: overdrafts, interest charges, shares, and trustee records.

Insurance Insurance companies are keeping all records up-to-date with the help of computers. The insurance companies, finance houses and stock broking firms are widely using computers for their concerns. Insurance companies are maintaining a database of all clients with information showing

Education

The computer has provided a lot of facilities in the education system.

Based Education). f number of computer students. educate the students. carried out on this basis.

Marketing In marketing, uses of computer are following: 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. At 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. Health Care Computers have become important part in hospitals, labs, and dispensaries. The computers are being used in hospitals to keep the record of patients and medicines. It is also used in scanning and diagnosing different diseases. ECG, EEG, Ultrasounds and CT Scans etc. are also done by computerised machines. Some major fields of health care in which computers are used are: Diagnostic System - Computers are used to collect data and identify cause of illness. Lab-diagnostic System - All tests can be done and reports are prepared by

computer. Patient Monitoring System - These are used to check patient's signs for abnormality such as in Cardiac Arrest, ECG etc. Pharma Information System - Computer checks Drug-Labels, Expiry dates, harmful

drug’s side effects etc. Surgery: Nowadays, computers are also used in performing surgery.

Engineering Design

Computers are widely used in Engineering purpose. One of major areas is CAD (Computer aided design).that provides creation and modification of images. Some fields 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 equipments. Architectural Engineering - Computers help in planning towns, designing buildings,

determining a range of buildings on a site using both 2D and 3D drawings.

Military Computers are largely used in defence. modern tanks, missiles, weapons etc. Military also employs computerised control systems. Some military areas where a computer has been used are:

Communication Communication means to convey a message, an idea, a picture or speech that is received and understood clearly and correctly by the person for whom it is meant for. Some main areas in this category are: -mail -conferencing

Government Computers play an important role in government. Some major fields in this category are: n of driving licensing system Computer Hardware

Hardware represents the physical and tangible components of a computer i.e. the components that can be seen and touched. Examples of Hardware are following: Input devices -- keyboard, mouse etc. Output devices -- printer, monitor etc. Secondary storage devices -- Hard disk, CD, DVD etc. Internal components -- CPU, motherboard, RAM etc.

Input Devices

Input devices accept data and instructions from the user.

Following are the examples of various input devices, which are connected to the computer for this purpose. 1. Keyboard 2. Mouse 3. Light Pen 4. Scanner

5. Touch Screen 6. Microphone 7. Track Ball 8. Digitizing Tablet 9. MICR 10.OCR

11.OMR 12.Barcode reader 13.Webcam 14. Digital camera 15.Point of scale

16.Touch pad 17.smart card Keyboard A keyboard is the most common input device. Several kinds of keyboards are available, but they resemble each other with minor variations. The keyboard in most common use is the QWERTY board. Generally standard keyboard has 104 keys. In these keyboards, the cursor control keys are duplicated to allow easier use of the numeric pad. Mouse

A mouse is an electro-mechanical, hand-held. It is used as a pointer. It can perform functions like selecting menu commands, moving icons, resizing windows, starting programs, and choosing options.

The most common mouse uses an internal, magnetically coated ball, to detect the movement of the mouse across a flat surface, usually a desktop. Now a days Optical or laser mouse is used to detect the movement. All windows based applications today are designed to work with a mouse. A mouse is used to replace hard -to-remember key combinations with easier "Point and Click" actions. However, it cannot substitute all keyboard operations. It can be alternative for commands based operations.

Light pen An input device that utilizes a light-sensitive detector to select objects on a display screen. A light pen is similar to a mouse except that with a light pen you can move the pointer and select objects on the display screen by directly pointing to the objects with the pen. Scanner These devices are used for automatic data collection. The devices of this category completely eliminate manual input of data. For example, the bar-code reader is actually just a special type of image scanner. An image scanner translates printed images into an electronic format that can be stored in a computer’s memory, and with the right kind of software, one can alter a stored image. Another example of scanner is optical character recognition (OCR) device, used by banks to convert the scanned image of a typed or printed page into text that can be edited on the computer.

Touch Screen Touch panel displays and pads are now being offered as alternatives to keyboard. Here the input can be given through the computer screen, that accepts the input through monitor; users touch electronic buttons displayed on the screen or they may use light pen.

Microphone Microphone is an input device, which takes voice as input. The voice communication is more error-prone than information through keyboard. There are two types of microphones available 1. Desktop Microphone 2. Hand held Microphone

Track Ball

Trackball, a pointing device, is a mouse lying on its back to move the pointer; you rotate the ball with your thumb, your fingers, or the palm of your hand. There are usually one to three buttons next to the ball, which you use just like mouse buttons. The advantage of trackballs over mouse is that the trackball is stationary so it does not require much space to use it. In addition, you can place a trackball on any type of surface, including your lap. For both these

reasons, trackballs are popular pointing devices for portable computers.

Digitizing tablet An input device that enables you to enter drawings and sketches into a computer. A digitizing tablet consists of an electronic tablet and a cursor or pen. A cursor (also called a puck) is similar to a mouse, except that it has a window with cross hairs for pinpoint placement, and it can have as many as 16 buttons. A pen (also called a stylus) looks like a simple ballpoint pen but uses an electronic head instead of ink. The tablet contains electronics that enable it to detect movement of the cursor or pen and translate the movements into digital signals that it sends to the computer. For digitizing tablets, each point on the tablet represents a point on the display screen in a fixed manner. This differs from mice, in which all movement is relative to the current cursor position. The static nature of digitizing tablets makes them particularly effective for tracing drawings. Most modern digitizing tablets also support a mouse emulation mode , in which the pen or cursor acts like a mouse. Digitizing tablets are also called digitizers, graphics tablets, touch tablets, or simply tablets.

MICR(Magnetic ink character reader) MICR input device is generally used in banks because of a large number of cheques to be processed every day. The bank's code number and cheque number are printed on the cheques with a special type of ink that contains particles of magnetic material that are machine readable. This reading process is called Magnetic Ink Character Recognition (MICR). The main advantages of MICR is that it is fast and less error prone.

OCR (Optical Character reader) OCR is an input device used to read a printed text. OCR scans text optically character by character, converts them into a machine readable code and stores the text on the system memory.

OMR (Optical mark reader) OMR is a special type of optical scanner used to recognize the type of mark made by pen or pencil. It is used where one out of a few alternatives is to be selected and marked. It is specially used for checking the answer sheets of examinations having multiple choice questions.

Barcode Reader Bar Code Reader is a device used for reading bar coded data (data in form of light and dark lines). Bar coded data is generally used in labelling goods, numbering the books etc. It may be a hand held scanner or may be embedded in a stationary scanner. Bar Code Reader scans a bar code image, converts it into an alphanumeric value which is then fed to the computer to which bar code reader is connected.

Webcam A webcam is a video camera that feeds or streams its image in real time to or through

a computer to computer network. When "captured" by the computer, the video stream may be saved, viewed or sent on to other networks via systems such as the internet, and email as an attachment. When sent to a remote location, the video stream may be saved, viewed or on sent there. Unlike an IP camera(which connects using Ethernet or Wi-Fi), a webcam is generally connected by a USB cable, or similar cable, or built into computer hardware, such as laptops.

Digital camera

A digital camera or digicam is a camera that encodes digital images and videos digitally and

stores them for later reproduction.[1] Most cameras sold today are digital,[2] and digital cameras are incorporated into many devices ranging from PDAs and mobile phones (called camera phones) to vehicles.

Digital and movie cameras share an optical system, typically using a lens with a variable diaphragm to focus light onto an image pickup device. The diaphragm and shutter admit the correct amount of light to the imager, just as with film but the image pickup

device is electronic rather than chemical. However, unlike film cameras, digital cameras can display images on a screen immediately after being recorded, and store and delete images from memory. Many digital cameras can also record moving videos with sound. Some digital cameras can crop and stitch pictures and perform other elementary image editing.

Point of Scale

POS or PoS is an abbreviation for Point of Sale (or Point-of-Sale, or Point of Service). The term

is applicable to a retail shop or store, the checkout/cashier counter in the store, or a location

where such transactions can occur in this type of environment. It can also apply to the actual

Point of Sale (POS) Hardware & Software including but not limited to electronic cash register

systems, touch-screen display, barcode scanners, receipt printers, scales and pole displays.

Point of Sale Systems are utilized in many different industries, ranging from restaurants, hotels

& hospitality businesses, nail/beauty salons, casinos, stadiums, and let's not forget - the retail

environments. In the most basic sense, if something can be exchanged for monetary value - a

Point of Sale System can be used.

Touchpad

A touchpad is a pointing device featuring a tactile sensor, a specialized surface that can

translate the motion and position of a user's fingers to a relative position on the operating system that is outputted to the screen. Touchpads are a common feature of laptop computers, and are also used as a substitute for a mouse where desk space is scarce. Because they vary in size, they can also be found on personal digital assistants (PDAs) and some portable media players. Wireless touchpads are also available as detached accessories.

Smart card A smart card, chip card, or integrated circuit card (ICC) is any pocket-sized card that has embedded integrated circuits.[1] Smart cards are made of plastic, generally polyvinyl chloride, but sometimes polyethylene terephthalate based polyesters, acrylonitrile butadiene styrene or polycarbonate. Since April 2009, a Japanese company has manufactured reusable financial smart cards made from paper.

Smart cards can be either contact or contactless smart card. Smart cards can provide personal

identification, authentication, data storage, and application processing.[3] Smart cards may

provide strong security authentication for single sign-on (SSO) within large organizations.

Output Devices

Output devices return processed data that is information, back to the user. Some of the commonly used output devices are: 1. Monitor (Visual Display Unit) 2. Printers 3. Plotter 4. Speakers

Monitor Out of all the output devices, monitor is perhaps the most important output device because people interact with this device most intensively than others. Computer information is displayed, visually with a video adapter card and monitor. Information processed within the CPU, that needs to be visually displayed, is sent to video adapter. The video adapter converts information from the format used, in the same manner as a television displays information sent to it by a cable service.

Two basic types of monitors are used with microcomputers, which are as follows: 1. CRT 2. LCD

Cathode Ray Tube (CRT): CRT or Cathode Ray Tube Monitor is the typical monitor that you

see on a desktop computer. It looks a lot like a television screen, and works the same way. This type uses a large vacuum tube, called cathode ray tube (CRT). Liquid Crystal Displays (LCD): This type of monitors are also known as flat panel monitor.

Most of these employ liquid crystal displays (LCDs) to render images. These days LCD monitor are very popular.

Printer After a document is created on the computer, it can be sent to a printer for a hard copy (printout). Some printers offer special features such as colored and large page formats. Some of the most commonly used printers are: 1. Laser Printer 2. Ink Jet Printer 3. Dot Matrix Printer 4. Line Printer

Laser Printer: A laser printer produces high quality print that one normally finds in publishing. It

is extremely fast and quiet. Moreover, the operation of a laser printer is easy with automatic paper loading and no smudging or messing up of ink ribbons. The fastest laser printer can print up to 200 pages per minute in monochrome (black and white) and up to 100 pages per minute in color.

Ink-Jet Printer: An ink-jet printer creates an image directly on paper by spraying ink through as

many as 64 tiny nozzles. Although the image it produces is not generally quite as sharp as the output of a laser printer, the quality of ink-jet images is still high. Dot Matrix Printer: The dot matrix printer was very popular at one point of time. It is a very

versatile and inexpensive output device. In dot matrix printer the print head physically "hits" the paper through the ribbon and produces text (or images) by combinations of dots; hence the name dot matrix printer. Its speed is measured in characters per second (CPS). Although it is less expensive, it is louder, slower and produces lower print quality. Plotter A plotter is a special kind of output device that, like a printer, produces images on paper, but does so in a different way. Plotters are designed to produce large drawings or images, such as construction plans for buildings or blueprints for mechanical objects. A plotter can be connected to the port normally used by a printer. An array of different colored pens in a clip rack and a robotic arm is part of plotter. The instructions that a plotter receives from a computer consist of a color, and beginning and ending coordinates for a line. With that information, the plotter picks up the appropriate pen through its arm, positions it at the beginning coordinates drops the pen down to the surface of the paper and draws to the ending coordinates. Plotters draw curves by creating a sequence of very short straight lines. Speaker

Speakers are another type of output device, which allow you to listen to voice like music and conversation with people.

Memory

Primary memory

Primary storage unit is used for four activities – Input/output operations; Manipulations of text

and calculation operation; Logic/Comparison operation; Storage and retrieval operations.

Primary memory is the memory is place, which is used to store the currently running program

and the data being processed and their results. This is generally a temporary storage area. It is

used when small amount of data have to be exchanged quickly and used repeatedly. It is a very

fast memory but is of small storage capacity. Examples of Primary memory are RAM, ROM,

Cache Memory etc.

RAM (Random Access Memory)

RAM is used by the computer as a temporary storage area for the things it is using. Any data

that you are using or inputting is temporarily stored in the RAM, where it can be manipulated

and used by the computer. Its capacity is usually measured in MB (Megabyte). It is volatile and

holds data until the power is on.

ROM (Read Only Memory)

It is where your computer stores instructions that it uses when it boots (starts) up. ROM is non-

volatile memory. That is to say, any information stored in ROM remains intact even when the

computer is powered off. ROM (read-only memory): Computers almost always contain a small

amount of read-only memory that holds instructions for starting up the computer. Unlike RAM,

ROM cannot be written to.

Types of ROM

PROM (PROGRAMMABLE READ ONLY MEMORY) is read-only memory that can be modified

only once by a user. The user buys a blank PROM and enters the desired contents using a PROM program. Inside the PROM chip there are small fuses which are burnt open during programming. It can be programmed only once and is not erasable. EPROM (ERASABLE AND PROGRAMMABLE READ ONLY MEMORY)

The EPROM can be erased by exposing it to ultra-violet light for a duration of up to 40 minutes. Usually, an EPROM eraser achieves this function. During programming, an electrical charge is trapped in an insulated gate region. The charge is retained for more than ten years because the charge has no leakage path. For erasing this charge, ultra-violet light is passed through a quartz crystal window(lid). This exposure to ultra-violet light dissipates the charge. During normal use the quartz lid is sealed with a sticker. EEPROM (ELECTRICALLY ERASABLE AND PROGRAMMABLE READ ONLY MEMORY)

The EEPROM is programmed and erased electrically. It can be erased and reprogrammed about ten thousand times. Both erasing and programming take about 4 to 10 ms (milli second). In EEPROM, any location can be selectively erased and programmed. EEPROMs can be erased one byte at a time, rather than erasing the entire chip. Hence, the process of re-programming is flexible but slow.

Cache memory A buffer, smaller and faster than main storage, used to hold a copy of instructions and data in

main storage that are likely to be needed next by the processor and that have been obtained

automatically from main storage. It is pronounced cash, a special high-

speed storage mechanism. It can be either a reserved section of main memory or an

independent high-speed storage device. Two types of caching are commonly used in personal

computers: memory caching and disk caching.

A memory cache, sometimes called a cache store or RAM cache, is a portion of memory made

of high-speed static RAM (SRAM) instead of the slower and cheaper dynamic RAM (DRAM)

used for main memory. Memory caching is effective because most programs access the

same data or instructions over and over. By keeping as much of this information as possible in

SRAM, the computer avoids accessing the slower DRAM.

Secondary Memory

This is also called Mass Storage, Auxiliary Memory and External Memory. This memory is

slower than the Main memory as it involves mechanical motion techniques during storage and

retrieval of data. This memory is larger in size than Main memory but the processor is unable to

access it directly due to its offline link with the processor. This means that the data from

secondary storage must be loaded into RAM before the processor starts processing it. The main

memory links the secondary memory to the processor.

Types of Secondary Memory

Magnetic Disks

Speedy access to data, relatively low cost, and the ability to erase and rewrite data make

magnetic disks the most widely used storage media on today’s computers. With magnetic disk

storage systems, data are written by read/write heads magnetizing the particles a certain way

on a medium surface. The particles retain their magnetic orientation so they can be read at a

later time, and rewriting to the medium is possible. There are two main types of magnetic disks:

FLOPPY DISK:

Floppy Disk is a round, flat piece of Mylar coated with ferric oxide, rust like substance containing

tiny particles capable of holding a magnetic field, and encased in a protective plastic cover, the

disk jacket. Data is stored on a floppy disk by the disk drive's read/write head, which alters the

magnetic orientation of the particles. Orientation in one direction represents binary 1; orientation

in the other, binary 0. Typically, a floppy disk is 5.25 inches in diameter, with a large hole in the

center that fits around the spindle in the disk drive. Depending on its capacity, such a disk can

hold from a few hundred thousand to over one million bytes of data. A 3.5-inch disk encased in

rigid plastic is usually called a microfloppy disk but can also be called a floppy disk.

HARD DISK:

Hard Disk composed of one or more platters that are permanently sealed within a hard metallic

casing. These hard disks are fixed in the computer CPU and are seldom transferred from one

computer to another. For the better use of the hard disk space, a hard disk can be divided into

any number of partitions like C: D: E: etc. however making too many partitions is not a good

management practice for the memory of hard disk.

Now days up to 1000 GB hard disks are available in the market. For the better use of disk space

a hard disk can be divided into a number of partitions like C: D: E: etc.

Magnetic Tapes:

Magnetic tape and the tape drives are analogous to a home tape recorder system. It uses the same

reading and recording techniques as that of the magnetic disk as the medium used in it is a flex ible tape

that is coated with magnetic oxide.

Since sequential access device means that for n records, where n = 0, 1, 2, 3, ……… if the tape head is

positioned at record number 1 then in order to read the nth record, it is necessary to read all the

physical records from 1st to nth records one at a time. If the head position is beyond the desired record,

it is necessary to rewind the tape for a specific distance and begin reading forward.

In contrast to the magnetic disk, which is a direct access device, a tape is sequential in nature. A disk

drive doesn’t read all the sectors on a disk sequentially to get to the desired record, where as magnetic

tape drive read all the sectors b/w the starting and the desired location of data. Magnetic tape was the

first kind of secondary memory and is still widely used for its lowest cost, however it is very slow in

speed than all of the secondary storage devices.

Optical Memory

Optical memory is used for storing large volumes of data like sound, text, graphics, and videos.

An optical disk is a removable disk that uses laser to read and write data. With an optical disk,

there is no mechanical arm, as with floppy disks and hard disks. Instead a high-power laser

beam is used to write data by burning tiny pits into the surface of a hard plastic disk. To read the

data, a low-power laser light scans the disk surface: pitted areas are not reflected and are

interpreted as 0 bits; smooth areas are reflected and are interpreted as 1 bits. Because the pits

are so tiny, a great deal more data can be represented than is possible in the same amount of

space on hard disks. An optical disk can hold over 4.7 gigabytes of data, the equivalent of 1

million type-written pages.

The optical memory devices are:

Compact Disk (CD)

CD is a non-erasable disk that stores the digitized audio information. The standard system uses

12 cm disks and they can record more than 60 minutes of playing time without any interruption.

CD-ROM

Optical disk form of secondary storage that is used to hold prerecorded text, graphics and

sound. Like music CDs a CD-ROM is a read-only disk. Read Only means the disk’s content is

recorded at the time of manufacture and can not be written on or erased by the user. A CD-

ROM disk can hold up to 650 MB of data, equal to 300,000 pages of text.

CR-RW

CD-RW (Compact Disk-Rewritable) also called as Erasable Optical Disk allow users to record

and erase data so that the disk can be used over and over again. Special CD-RW drives and

software is required.

DVD (Digital Versatile Disk) : the “Digital Convergence” Disk

The DVD represents a new generation of high density CD-ROM disks, which are read by laser

and which have both write-once and rewritable capabilities. According to the various industries

sponsoring it, DVD stands for either ―Digital Video Disk‖ or ―Digital Versatile Disk‖, and it is a CD

type disk with extremely high capacity, able to store 4.7-17 GB.

DVD-R

DVD disks that allow one time recording by the consumer. Two types of reusable disks are

DVD-RW (DVD Rewritable) and DVD-RAM (DVD Random Access Memory), both of which can

be recorded on and erased more than once.

Write Once Read Many (WORM)

WORM is a disk that is more easily written than CD-ROM thus making single copy disks

commercially feasible. After performing the write operation the disk is read only. The most

popular size is 51/4 ―that can hold data from 200 to 800 MB.

Magneto-Optical Disk

There are a few other types of storage systems that use a combination of magnetic and optical

technology – the magneto-optical disk is one of them. M-O disks can store up to 5.2 GB of data.

A very common application of Optical Memory especially CD-ROM is that it can store

Multimedia Encyclopedia that contains all 21 volumes of the Academic American Encyclopedia.

This encyclopedia comprises full text of about 33000 as well as a comprehensive index of titles,

words, pictures and maps. In addition there are thousands of pictures, hundreds of sounds and

animations along with dozens of video clips.

CPU (CENTRAL PROCESSING UNIT) CPU consists of the following features: of computer. CPU itself has following three components.

Memory or Storage Unit: This unit can store instructions, data and intermediate results. This unit supplies information to the other units of the computer when needed. It is also known as internal storage unit or main memory or primary storage or Random access memory(RAM). Its size affects speed, power and capability. Primary memory and secondary memory are two types of memories in the computer. Functions of memory unit are: of processing. device.

Control Unit

This unit controls the operations of all parts of computer but does not carry out any actual data processing operations.

Functions of this unit are: of a computer. It obtains the instructions from the memory, interprets them, and directs the operation of the computer.

ALU (Arithmetic Logic Unit) This unit consists of two subsections namely Arithmetic section

Function of arithmetic section is to perform arithmetic operations like addition, subtraction, multiplication and division. All complex operations are done by making repetitive use of above operations. Logic Section

Function of logic section is to perform logic operations such as comparing, selecting, matching and merging of data.

UNIT –II OPERATING SYSTEM AND NETWORKING Operating system

An operating system is a system software with following features: the computer hardware. is an integrated set of specialized programs that are used to manage overall resources and operations of the computer. programs that reside in the computer, including application programs and other system software.

An operating system (OS) is system software that manages computer hardware and software resources and

provides common services for computer programs. All computer programs, excluding firmware, require an

operating system to function.

Types of operating system

Batch operating system

The users of a batch operating system do not interact with the computer directly. Each user

prepares his job on an off-line device like punch cards and submits it to the computer operator.

To speed up processing, jobs with similar needs are batched together and run as a group. The

programmers leave their programs with the operator and the operator then sorts the programs

with similar requirements into batches.

The problems with Batch Systems are as follows −

Lack of interaction between the user and the job.

CPU is often idle, because the speed of the mechanical I/O devices is slower than the

CPU.

Difficult to provide the desired priority.

Time-sharing operating systems

Time-sharing is a technique which enables many people, located at various terminals, to use a

particular computer system at the same time. Time-sharing or multitasking is a logical

extension of multiprogramming. Processor's time which is shared among multiple users

simultaneously is termed as time-sharing.

The main difference between Multiprogrammed Batch Systems and Time-Sharing Systems is

that in case of Multiprogrammed batch systems, the objective is to maximize processor use,

whereas in Time-Sharing Systems, the objective is to minimize response time.

Multiple jobs are executed by the CPU by switching between them, but the switches occur so

frequently. Thus, the user can receive an immediate response. For example, in a transaction

processing, the processor executes each user program in a short burst or quantum of

computation. That is, if n users are present, then each user can get a time quantum. When the

user submits the command, the response time is in few seconds at most.

The operating system uses CPU scheduling and multiprogramming to provide each user with a

small portion of a time. Computer systems that were designed primarily as batch systems have

been modified to time-sharing systems.

Advantages of Timesharing operating systems are as follows −

Provides the advantage of quick response.

Avoids duplication of software.

Reduces CPU idle time.

Disadvantages of Time-sharing operating systems are as follows −

Problem of reliability.

Question of security and integrity of user programs and data.

Problem of data communication.

Distributed operating System

Distributed systems use multiple central processors to serve multiple real-time applications and

multiple users. Data processing jobs are distributed among the processors accordingly.

The processors communicate with one another through various communication lines (such as

high-speed buses or telephone lines). These are referred as loosely coupled systems or

distributed systems. Processors in a distributed system may vary in size and function. These

processors are referred as sites, nodes, computers, and so on.

The advantages of distributed systems are as follows −

With resource sharing facility, a user at one site may be able to use the resources

available at another.

Speedup the exchange of data with one another via electronic mail.

If one site fails in a distributed system, the remaining sites can potentially continue

operating.

Better service to the customers.

Reduction of the load on the host computer.

Reduction of delays in data processing.

Network operating System

A Network Operating System runs on a server and provides the server the capability to

manage data, users, groups, security, applications, and other networking functions. The

primary purpose of the network operating system is to allow shared file and printer access

among multiple computers in a network, typically a local area network (LAN), a private network

or to other networks.

Examples of network operating systems include Microsoft Windows Server 2003, Microsoft

Windows Server 2008, UNIX, Linux, Mac OS X, Novell NetWare, and BSD.

The advantages of network operating systems are as follows −

Centralized servers are highly stable.

Security is server managed.

Upgrades to new technologies and hardware can be easily integrated into the system.

Remote access to servers is possible from different locations and types of systems.

The disadvantages of network operating systems are as follows −

High cost of buying and running a server.

Dependency on a central location for most operations.

Regular maintenance and updates are required.

Real Time operating System

A real-time system is defined as a data processing system in which the time interval required to

process and respond to inputs is so small that it controls the environment. The time taken by

the system to respond to an input and display of required updated information is termed as

the response time. So in this method, the response time is very less as compared to online

processing.

Real-time systems are used when there are rigid time requirements on the operation of a

processor or the flow of data and real-time systems can be used as a control device in a

dedicated application. A real-time operating system must have well-defined, fixed time

constraints, otherwise the system will fail. For example, Scientific experiments, medical

imaging systems, industrial control systems, weapon systems, robots, air traffic control

systems, etc.

There are two types of real-time operating systems.

Hard real-time systems

Hard real-time systems guarantee that critical tasks complete on time. In hard real-time

systems, secondary storage is limited or missing and the data is stored in ROM. In these

systems, virtual memory is almost never found.

Soft real-time systems

Soft real-time systems are less restrictive. A critical real-time task gets priority over other tasks

and retains the priority until it completes. Soft real-time systems have limited utility than hard

real-time systems. For example, multimedia, virtual reality, Advanced Scientific Projects like

undersea exploration and planetary rovers, etc.

Evolution of Operating Systems

The evolution of operating systems is directly dependent to the development of computer systems and how users use them. Here is a quick tour of computing systems through the past fifty years in the timeline.

Early Evolution

1945: ENIAC, Moore School of Engineering, University of Pennsylvania.

1949: EDSAC and EDVAC

1949 BINAC - a successor to the ENIAC

1951: UNIVAC by Remington

1952: IBM 701

1956: The interrupt

1954-1957: FORTRAN was developed

Operating Systems by the late 1950s

By the late 1950s Operating systems were well improved and started supporting following usages :

It was able to Single stream batch processing

It could use Common, standardized, input/output routines for device access

Program transition capabilities to reduce the overhead of starting a new job was added

Error recovery to clean up after a job terminated abnormally was added.

Job control languages that allowed users to specify the job definition and resource requirements

were made possible.

Operating Systems In 1960s

1961: The dawn of minicomputers

1962 Compatible Time-Sharing System (CTSS) from MIT

1963 Burroughs Master Control Program (MCP) for the B5000 system

1964: IBM System/360

1960s: Disks become mainstream

1966: Minicomputers get cheaper, more powerful, and really useful

1967-1968: The mouse

1964 and onward: Multics

1969: The UNIX Time-Sharing System from Bell Telephone Laboratories

Supported OS Features by 1970s

Multi User and Multi tasking was introduced.

Dynamic address translation hardware and Virtual machines came into picture.

Modular architectures came into existence.

Personal, interactive systems came into existence.

Accomplishments after 1970

1971: Intel announces the microprocessor

1972: IBM comes out with VM: the Virtual Machine Operating System

1973: UNIX 4th Edition is published

1973: Ethernet

1974 The Personal Computer Age begins

1974: Gates and Allen wrote BASIC for the Altair

1976: Apple II

August 12, 1981: IBM introduces the IBM PC

1983 Microsoft begins work on MS-Windows

1984 Apple Macintosh comes out

1990 Microsoft Windows 3.0 comes out

1991 GNU/Linux

1992 The first Windows virus comes out

1993 Windows NT

2007: iOS

2008: Android OS

And the research and development work still goes on, with new operating systems being developed and existing ones being improved to enhance the overall user experience while making operating systems fast and efficient like they have never been

before.

Network types

Computer Network can be defined as a set or collection of computing devices that are linked to each

other in order to communicate and share their resources with each other. Networks on the basis of

their scale, scope and purpose,can be categorized as:

1. Local area network (LAN)

2.Wide area network (WAN) 3.Metropolitan area network (MAN)

Each one is explained in detail as follows:

1. Local Area Networks:

A LAN is a type of computer Network in which networking facility is available in a small physical

area (mostly in meters but very rarely in kilometers) probably in an office building,home,school or

places like airport,hostel etc. Each Computer or device connected to the network is called a node.A

LAN is useful for sharing resources like files, printers, games or other applications.

The distinguishing characters of LAN which separates it from other types of networks are:

1. Size of the LAN 2. Transmission technology used by LAN and 3. Network topology

LAN are restricted in size and due to this simplifies network management. LAN probably use a

transmission technology consisting of inexpensive hardware such as Ethernet cables, to which all

other devices or computers are attached. Speed of LAN ranges from 10 Mbps to 100 Mbps and thus

has an advantage of having low delay of microseconds or nanoseconds.

2. Wide Area Networks:

A wide area network (WAN) is a computer network that covers a broad area (i.e., any

network whose communications linkscross metropolitan, regional, or national boundaries). A

WAN covers a larger area by using communication channel s that include numerous telephone

lines,cables etc. A WAN can be thought of as a geographically -dispersed collection of LANs. LANS

are connected to WAN through a network device called a router. The Internet is the largest WAN

covering the Earth. WANs tend to use technology like ATM, Frame Relay and X.25 for connectivity

over the longer distances.

3. Metropolitan Area Network (MAN):

It is a type of network that covers an area larger than a LAN but smaller than a WAN e.g a city.The

best-known example of a MAN is the cable television network available in many cities. Functions of operating system Memory Management -- keeps tracks of primary memory i.e. what part of it is in use by

whom, what part is not in use etc. and allocates the memory when a process or program requests it. Processor Management -- allocates the processor(CPU) to a process and

deallocates processor when it is no longer required. Device Management -- keeps track of all devices. This is also called I/O controller

that decides which process gets the device, when, and for how much time. File Management -- allocates and de-allocates the resources and decides who gets

the resources. Security -- prevents unauthorized access to programs and data by means of

passwords and similar other techniques. Job accounting -- keeps track of time and resources used by various jobs and/or

users. Control over system performance -- records delays between request for a service

and from the system. Interaction with the operators -- The interaction may take place via the console of

the computer in the form of instructions. Operating System acknowledges the same, does the corresponding action and informs the operation by a display screen. Error-detecting aids -- Production of dumps, traces, error messages and other

debugging and error-detecting methods.

Coordination between other software and users -- Coordination and assignment of

compilers, interpreters, assemblers and other software to the various users of the computer systems. Software

As you are aware, computer cannot do anything on its own. It is the user who instructs computer; what to do, how to do and when to do. In order to perform any task, you have to give a set of instructions in a particular sequence to the computer. These sets of instructions are called Programs. Software refers to a set of programs that makes the hardware perform a particular set of tasks in particular order. Software can be classified mainly into following categories: System Software

When you switch on the computer the programs stored in ROM are executed which activates different units of your computer and makes it ready for you to work on it. This set of programs can be called system software. System software’s are sets of programs, responsible for running the computer, controlling various operations of computer systems and management of computer resources. Operating System (OS) falls under this category.

Application Software

Application software is a set of programs, which are written to perform specific tasks, for example: An application package for managing library known as library information system is used to manage information of library such as: keeping book details, account holder details, book issue details, book return details etc. Another application package for managing student details is called student’s information system, manages student’s roll no, name, parents name, address, class, section, processing of examination results etc.

What is a computer virus?

It is a program designed to replicate itself into other files or programs stored on your device. Viruses can cause programs to opperate incorrectly or corrupt a computer's momory.

Virus types

There are six broad categories that viruses fall under:

1. Boot Sector Virus - targets the boot sector of a hard drive and crucially effects the boot

process.

2. File Infection Virus - coded viruses that attach themselves to .exe files; compressed

files such as zip or drive files.

3. Multipartite Virus - cross between a file virus and a boot sector virus.

4. Network Virus - uniquely created to quickly spread throughout the local area network

and generally across the Internet as well. Typically moves within shared resources like

drives and folders.

5. Macro Virus - infects program files that use macros in the program itself, such as word

processors.

6. E-mail Virus - generally this is a macro virus which multiplies by sending itself to other

contacts in your address book, in hopes they'll activate the virus as well.

Control measures

Today, many "worm" viruses travel the internet actively seeking vulnerable computers. This

means that your computer can become infected just by connecting to the internet. Although new

viruses are being created all the time, there are some steps that you can take to protect your

computer.

Your most important defense is installing and regularly updating virus protection software.

Although anti-virus software is critical, it is no longer enough to provide maximum protection

alone. You should also run operating system updates regularly.

Windows users can install critical updates by opening Internet Explorer and then

choosing Tools and Windows Update from the menu.

Macintosh users can install updates by clicking on the Apple menu and choosing

Software Update

Flowchart

A flowchart is a type of diagram that uses an algorithm, workflow or process, showing

the steps as boxes of various kinds, and their order by connecting them with arrows.

This diagrammatic representation illustrates a solution model to a given problem.

Flowcharts are used in analysing, designing, documenting or managing a process or

program in various fields

UNIT-III NUMBER SYSTEM AND DATA INFORMATION CONCEPTS

When we type some letters or words, the computer translates them in numbers as computers can understand only numbers. A computer can understand positional number system where there are only a few symbols called digits and these symbols represent different values depending on the position they occupy in the number. A value of each digit in a number can be determined using gits available in the number system).

Decimal Number System

The number system that we use in our day-to-day life is the decimal number system. Decimal number system has base 10 as it uses 10 digits from 0 to 9. In decimal number system, the successive positions to the left of the decimal point represent units, tens, hundreds, thousands and so on.

Each position represents a specific power of the base (10). For example, the decimal number 1234 consists of the digit 4 in the units position, 3 in the tens position, 2 in the hundreds position, and 1 in the thousands position, and its value can be written as (1x1000)+ (2x100)+ (3x10)+ (4xl) (1x103)+ (2x102)+ (3x101)+ (4xl00) 1000 + 200 + 30 + 4 1234 As a computer programmer or an IT professional, you should understand the following number systems which are frequently used in computers.

1 Binary Number System

Base 2. Digits used: 0, 1 2 Octal Number System

Base 8. Digits used: 0 to 7 3 Hexa Decimal Number

System Base 16. Digits used: 0 to 9, Letters used: A- F

Binary Number System

Characteristics of binary number system are as follows Uses two digits, 0 and 1.

position in a binary number represents a 0 power of the base (2). Example 20 (2). Example 2x where x represents the last position - 1. Example: Binary Number: 101012 Calculating Decimal Equivalent: Step Binary

Number Decimal Number

Step 1

101012 ((1 x 24) + (0 x 23) + (1 x 22) + (0 x 21) + (1 x 20))10

Step 2

101012 (16 + 0 + 4 + 0 + 1)10

Step 3

101012 2110

Note: 101012 is normally written as 10101.

Octal number system Characteristics of octal number system are as follows (8). Example 80 (8). Example 8x where x represents the last position - 1. Example: Octal Number: 125708

Calculating Decimal Equivalent: Step 1 125708 ((1 x 84) + (2 x 83) + (5 x 82) + (7 x 81) + (0 x 80))10 Step 2 125708 (4096 + 1024 + 320 + 56 + 0)10 Step 3 125708 549610

Note: 125708 is normally written as 12570.

Hexa Decimal Number System Characteristics of hexadecimal number system are as follows 12, D = 13, E = 14, F = 15. base (16). Example 160 base (16). Example 16x where x represents the last position - 1. Example: Hexadecimal Number: 19FDE16 Calculating Decimal Equivalent: Step Binary

Number Decimal Number

Step 1

19FDE16 ((1 x 164) + (9 x 163) + (F x 162) + (D x 161) + (E x 160))10

Step 2

19FDE16 ((1 x 164) + (9 x 163) + (15 x 162) + (13 x 161) + (14 x 160))10

Step 3

19FDE16 (65536+ 36864 + 3840 + 208 + 14)10

Step 4

19FDE16 10646210

Note: 19FDE16 is normally written as 19FDE.

UNIT –IV ADVANCED TRENDS IN IT

MOBILE INTERNET

The mobile Web refers to the use of browser-based Internet services from

handheld mobile devices, such as smartphones or feature phones, through a

mobile or other wireless network.

Traditionally, access to the World Wide Web has been via fixed-line services

on laptops and desktop computers. However, the Web is becoming more

accessible by portable and wireless devices. An early 2010 ITU (International

Telecommunication Union) report said that with the current growth rates, web

access by people on the go — via laptops and smart mobile devices – is

likely to exceed web access from desktop computers within the next five

years.[1] In January 2014 the time of mobile access to the internet exceeded

desktop use in the USA. The shift to mobile Web access has been

accelerating with the rise since 2007 of larger multi touch smartphones, and

of multi touch tablet computers since 2010. Both platforms provide better

Internet access, screens, and mobile browsers- or application-based user

Web experiences than previous generations of mobile devices have

done. Web designers may work separately on such pages, or pages may be

automatically converted as in Mobile Wikipedia.

GPS (Global Positioning System)

The Global Positioning System (GPS) is a satellite-based navigation system

made up of a network of 24 satellites placed into orbit by the U.S. Department

of Defense. GPS was originally intended for military applications, but in the

1980s, the government made the system available for civilian use. GPS

works in any weather conditions, anywhere in the world, 24 hours a day.

There are no subscription fees or setup charges to use GPS.

How it works

GPS satellites circle the earth twice a day in a very precise orbit and transmit

signal information to earth. GPS receivers take this information and use

trilateration to calculate the user's exact location. Essentially, the GPS

receiver compares the time a signal was transmitted by a satellite with the

time it was received. The time difference tells the GPS receiver how far away

the satellite is. Now, with distance measurements from a few more satellites,

the receiver can determine the user's position and display it on the unit's

electronic map.

2G, 3G, 4G

2G technology was suitable for making calls and sending text messages while 3G makes it possible to access the internet more effectively through your mobile phone.

4G services make it much quicker to surf the web on your mobile, tablets and laptops.

Because of this, 4G is ideally suited for services which demand more capacity like video streaming, mapping and social networking sites.

For the typical user, download speeds of initial 4G networks could be around 5-7 times those for existing 3G networks.

This means a music album taking 20 minutes to download on a 3G phone and just over 3 minutes on 4G. This is based on existing 3G speeds being 1Mbit/s on average and 4G speed being 6Mbit/s (average of 5 and 7 times faster).

WIFI (WIRELESS FEDILITY)

Wi-Fi or WiFi (/ˈwaɪ faɪ/) is a technology that allows electronic devices to

connect to a wireless LAN (WLAN) network, mainly using the 2.4 gigahertz

(12 cm) UHF and 5 gigahertz (6 cm) SHF ISM radio bands. A WLAN is

usually password protected, but may be open, which allows any device within

its range to access the resources of the WLAN network.

The Wi-Fi Alliance defines Wi-Fi as any "wireless local area network" (WLAN)

product based on the Institute of Electrical and Electronics Engineers'

(IEEE)802.11 standards. "Wi-Fi" is a trademark of the Wi-Fi Alliance. The

"Wi-Fi Certified" trademark can only be used by Wi-Fi products that

successfully complete Wi-Fi Alliance interoperability certification testing.

Devices that can use Wi-Fi technology include personal computers, video-

game consoles, smartphones, digital cameras, tablet computers, digital audio

players and modern printers. Wi-Fi compatible devices can connect to the

Internet via a WLAN network and a wireless access point. Such an access

point (or hotspot) has a range of about 20 meters (66 feet) indoors and a

greater range outdoors. Hotspot coverage can be as small as a single room

with walls that block radio waves, or as large as many square kilometres

achieved by using multiple overlapping access points.

Bluetooth

Bluetooth is a wireless technology standard for exchanging data over

short distances (using short-wavelength UHF radio waves in the ISM

band from 2.4 to 2.485 GHz[4]) from fixed and mobile devices, and

building personal area networks (PANs). Invented by telecom

vendor Ericsson in 1994,[5] it was originally conceived as a wireless

alternative to RS-232 data cables. It can connect several devices,

overcoming problems of synchronization.

Bluetooth is managed by the Bluetooth Special Interest Group (SIG),

which has more than 25,000 member companies in the areas of

telecommunication, computing, networking, and consumer

electronics.[6] The IEEE standardized Bluetooth as IEEE 802.15.1, but

no longer maintains the standard. The Bluetooth SIG oversees

development of the specification, manages the qualification program,

and protects the trademarks.[7] A manufacturer must meet Bluetooth

SIG standards to market it as a Bluetooth device.[8] A network

of patents apply to the technology, which are licensed to individual

qualifying devices.

SOCIAL NETWORKING

Social networking is the practice of expanding the number of one's

business and/or social contacts by making connections through

individuals, often through social media sites such

as Facebook, Twitter, LinkedIn and Google+.

Based on the six degrees of separation concept (the idea that any two

people on the planet could make contact through a chain of no more

than five intermediaries), social networking establishes interconnected

online communities (sometimes known as social graphs) that help

people make contacts that would be good for them to know, but that

they would be unlikely to have met otherwise.

Depending on the social media platform, members may be able to

contact any other member. In other cases, members can contact

anyone they have a connection to, and subsequently anyone that

contact has a connection to, and so on. Some services require

members to have a preexisting connection to contact other members.

While social networking has gone on almost as long as societies

themselves have existed, the unparalleled potential of the Web to

facilitate such connections has led to an exponential and ongoing

expansion of that phenomenon. In addition to social media platforms,

the capacity for social interaction and collaboration is increasingly built

into business applications.

CLOUD COMPUTING TECHNOLOGY

Cloud computing is a type of Internet-based computing that provides shared

computer processing resources and data to computers and other devices on

demand. It is a model for enabling ubiquitous, on-demand access to a shared

pool of configurable computing resources (e.g., computer networks, servers,

storage, applications and services),[1][2] which can be rapidly provisioned and

released with minimal management effort. Cloud computing and storage

solutions provide users and enterprises with various capabilities to store and

process their data in third-party data centers[3] that may be located far from

the user–ranging in distance from across a city to across the world. Cloud

computing relies on sharing of resources to achieve coherence and economy

of scale, similar to a utility (like the electricity grid) over an electricity network.

VLAN TECHNOLOGY

A virtual LAN (VLAN) is any broadcast domain that is partitioned and isolated

in a computer network at the data link layer(OSI layer 2).[1][2] LAN is an

abbreviation for local area network.

To subdivide a network into virtual LANs, one configures network equipment.

Simpler equipment can partition only per physical port (if at all), in which case

each VLAN is connected with a dedicated network cable. More sophisticated

devices can mark packets through VLAN tagging, so that a single

interconnect (trunk) may be used to transport data for multiple VLANs. Since

VLANs share bandwidth, a VLAN trunk can use link aggregation, quality-of-

service prioritization, or both to route data efficiently.

VLANs allow network administrators to group hosts together even if the hosts

are not on the same network switch. This can greatly simplify network design

and deployment, because VLAN membership can be configured through

software. Without VLANs, grouping hosts according to their resource needs

necessitates the labor of relocating nodes or rewiring data links.

FIRE WALL

A firewall is a network security device that monitors incoming and outgoing

network traffic and decides whether to allow or block specific traffic based on

a defined set of security rules.

Firewalls have been a first line of defense in network security for over 25

years. They establish a barrier between secured and controlled internal

networks that can be trusted and untrusted outside networks, such as the

Internet.

A firewall can be hardware, software, or both.

M COMMERCE

M-commerce (mobile commerce) is the buying and selling of goods and

services through wireless handheld devices such as cellular telephone and

personal digital assistants (PDAs). Known as next-generation e-commerce,

m-commerce enables users to access the Internet without needing to find a

place to plug in. The emerging technology behind m-commerce, which is

based on the Wireless Application Protocol (WAP), has made far greater

strides in Europe, where mobile devices equipped with Web-ready micro-

browsers are much more common than in the United States.

NANOTECHNOLOGY

Nanotechnology, or, as it is sometimes called, molecular manufacturing , is a

branch of engineering that deals with the design and manufacture of

extremely small electronic circuits and mechanical devices built at the

molecular level of matter. The Institute of Nanotechnology in the U.K.

expresses it as "science and technology where dimensions and tolerances in

the range of 0.1 nanometer (nm) to 100 nm play a critical role."

Nanotechnology is often discussed together with micro-electromechanical

systems ( MEMS), a subject that usually includes nanotechnology but may

also include technologies higher than the molecular level.

There is a limit to the number of components that can be fabricated onto

a semiconductor wafer or "chip.". Traditionally, circuits have been etched

onto chips by removing material in small regions. However, it is also possible

in theory to build chips up, one atom at a time, to obtain devices much

smaller than those that can be manufactured by etching. With this approach,

there would be no superfluous atoms; every particle would have a purpose.

Electrical conductors, called nanowire s, would be only one atom thick.

A logic gate would require only a few atoms. A data bit could be represented

by the presence or absence of a single electron .

VIRTUAL REALITY

Virtual reality (VR) typically refers to computer technologies that

use software to generate realistic images, sounds and other sensations that

replicate a real environment (or create an imaginary setting), and simulate a

user's physical presence in this environment, by enabling the user to interact

with this space and any objects depicted therein using specialized display

screens or projectors and other devices. VR has been defined as "...a

realistic and immersive simulation of a three-dimensional environment,

created using interactive software and hardware, and experienced or

controlled by movement of the body"[1] or as an "immersive, interactive

experience generated by a computer".[2] A person using virtual reality

equipment is typically able to "look around" the artificial world, move about in

it and interact with features or items that are depicted on a screen or in

goggles. Virtual realities artificially create sensory experiences, which can

include sight, touch, hearing, and, less commonly, smell. Most 2016-era

virtual realities are displayed either on a computer monitor, a projector

screen, or with a virtual reality headset (also called head-mounted display or

HMD). HMDs typically take the form of head-mounted goggles with a screen

in front of the eyes. Some simulations include additional sensory information

and provide sounds through speakers or headphones. Virtual Reality actually

brings the user into the digital world by cutting off outside stimuli. In this way

user is solely focusing on the digital content.

What is BPO?

Business Process Outsourcing or BPO is outsourcing of some of the

business functions to a third party in order to save money. It usually consists

of the back office or front office operations. While front office services are

related to client interaction and customer support, back office services are

related to finance and HR. If outsourcing is done to a company situated

outside the parent company's country, it is known as offshore outsourcing.

What is KPO?

Knowledge Process Outsourcing or KPO is a subset of BPO. KPO involves

outsourcing of core functions which may or may not give cost benefit to the

parent company but surely helps in value addition. The processes which are

outsourced to KPOs are usually more specialized and knowledge based as

compared to BPOs. Services included in KPO are related to R&D, Capital

and insurance market services, legal services, biotechnology, animation and

design, etc. are the usual activities that are outsourced to KPOs. LPO or

Legal Process Outsourcing is special type of KPO dealing with legal services.

YOUTUBE

YouTube is an American video-sharing website headquartered in San Bruno,

California, United States. The service was created by three former

PayPal employees in February 2005. In November 2006, it was bought by

Google for US$1.65 billion.[4] YouTube now operates as one of Google's

subsidiaries The site allows users to upload, view, rate, share, and comment

on videos, and it makes use of WebM, H.264/MPEG-4 AVC, and

Adobe Flash Video technology to display a wide variety of user-generated

and corporate media videos. Available content includes video clips, TV

show clips, music videos, audio recordings, movie trailers, and other content

such as video blogging, short original videos, and educational videos.

FACEBOOK

Facebook (stylized as facebook) is an American for-profit corporation and

online social media and social networking service based in Menlo Park,

California, United States. The Facebook website was launched on February

4, 2004, by Mark Zuckerberg, along with fellow Harvard College students and

roommates, Eduardo Saverin, Andrew McCollum,Dustin Moskovitz, and Chris

Hughes.

The founders had initially limited the website's membership to Harvard

students; however, later they expanded it to higher education institutions in

the Boston area, the Ivy League schools, and Stanford University. Facebook

gradually added support for students at various other universities, and

eventually to high school students as well. Since 2006, anyone age 13 and

older has been allowed to become a registered user of Facebook, though

variations exist in the minimum age requirement, depending on applicable

local laws.[10] The Facebook name comes from the face book directories often

given to United States university students.

ORKUT

Orkut was a social networking website owned and operated by Google. The

service was designed to help users meet new and old friends and maintain

existing relationships. The website was named after its creator, Google

employee Orkut Büyükkökten.

On June 30, 2014, Google announced it would be closing Orkut on

September 30, 2014. No new accounts could be created starting from July

2014. Users can download their profile archive by Google Takeout.[3]

Orkut was one of the most visited websites in India and Brazil in 2008.[4] In

2008 Google announced that Orkut would be fully managed and operated in

Brazil, by Google Brazil, in the city of Belo Horizonte. This was decided due

to the large Brazilian user base and growth of legal issues

LINKEDIN

inkedIn (/ˌliŋkt.ˈɪn/; stylized as Linked in) is a business and employment-

oriented social networking service that operates via websites. Founded on

December 14, 2002 and launched on May 5, 2003 it is mainly used

for professional networking, including employers posting jobs and job seekers

posting their CVs. As of 2015, most of the site's revenue came

from selling access to information about its users to recruiters and sales

professionals As of March 2016, LinkedIn has more than 433 million

accounts, out of which more than 106 million are active LinkedIn allows users

(workers and employers) to create profiles and "connections" to each other in

an online social network which may represent real-world professional

relationships. Users can invite anyone (whether a site user or not) to become

a connection The site has an Alexa Internet ranking as the 14th most popular

website (October 2016)

WWW (World Wide Web)

The World Wide Web (abbreviated WWW or the Web) is aninformation

space where documents and other web resources are identified by Uniform

Resource Locators (URLs), interlinked byhypertext links, and can be

accessed via the Internet.[1] English scientist Tim Berners-Lee invented the

World Wide Web in 1989. He wrote the first web browser computer

programme in 1990 while employed at CERN in Switzerland.[2][3][page needed]

The World Wide Web has been central to the development of theInformation

Age and is the primary tool billions of people use to interact on the

Internet.[4][5][6] Web pages are primarily text documentsformatted and

annotated with Hypertext Markup Language (HTML). In addition to formatted

text, web pages may contain images, video,audio, and software components

that are rendered in the user's web browser as coherent pages

of multimedia content. Embedded hyperlinks permit users

to navigate between web pages. Multiple web pages with a common theme, a

commondomain name, or both, make up a website. Website content can

largely be provided by the publisher, or interactive where users contribute

content or the content depends upon the user or their actions. Websites may

be mostly informative, primarily for entertainment, or largely for commercial,

governmental, or non-governmental organisational purposes.

WEB BROWSER

A web browser (commonly referred to as a browser) is a software

application for retrieving, presenting, and traversing information resources on

the World Wide Web. An information resource is identified by a Uniform

Resource Identifier(URI/URL) and may be a web page, image, video or other

piece of content.[1]Hyperlinks present in resources enable users easily to

navigate their browsers to related resources.

Although browsers are primarily intended to use the World Wide Web, they

can also be used to access information provided by web servers in private

networks or files in file systems.

The major web browsers are Firefox, Google Chrome, Internet

Explorer/Microsoft Edge,[2][3][4] Opera, and Safari.

IP ADDRESS

An IP address is a fascinating product of modern computer technology

designed to allow one computer (or other digital device) to communicate with

another via the Internet. IP addresses allow the location of literally billions of

digital devices that are connected to the Internet to be pinpointed and

differentiated from other devices. In the same sense that someone needs

your mailing address to send you a letter, a remote computer needs your IP

address to communicate with your computer.

"IP" stands for Internet Protocol, so an IP address is an Internet Protocol

address. What does that mean? An Internet Protocol is a set of rules that

govern Internet activity and facilitate completion of a variety of actions on the

World Wide Web. Therefore an Internet Protocol address is part of the

systematically laid out interconnected grid that governs online communication

by identifying both initiating devices and various Internet destinations, thereby

making two-way communication possible.

An IP address consists of four numbers, each of which contains one to three

digits, with a single dot (.) separating each number or set of digits. Each of

the four numbers can range from 0 to 255. Here's an example of what an IP

address might look like: 78.125.0.209. This innocuous-looking group of four

numbers is the key that empowers you and me to send and retrieve data over

our Internet connections, ensuring that our messages, as well as our

requests for data and the data we've requested, will reach their correct

Internet destinations. Without this numeric protocol, sending and receiving

data over the World Wide Web would be impossible.

IP addresses can be either static or dynamic. Static IP addresses never

change. They serve as a permanent Internet address and provide a simple

and reliable way for remote computers to contact you. Static IP addresses

reveal such information as the continent, country, region, and city in which a

computer is located; the ISP (Internet Service Provider) that services that

particular computer; and such technical information as the precise latitude

and longitude of the country, as well as the locale, of the computer. Many

websites provide IP address look-up services to their visitors, free of charge.

If you're curious about your own IP address, you can locate these websites

by performing a Google search.

Dynamic IP addresses are temporary and are assigned each time a computer

accesses the Internet. They are, in effect, borrowed from a pool of IP

addresses that are shared among various computers. Since a limited number

of static IP addresses are available, many ISPs reserve a portion of their

assigned addresses for sharing among their subscribers in this way. This

lowers costs and allows them to service far more subscribers than they

otherwise could.

Static IP addresses are generally preferable for such uses as VOIP(Voice

over Internet Protocol), online gaming, or any other purpose where users

need to make it easy for other computers to locate and connect to them. Easy

access can also be facilitated when using a dynamic IP address through the

use of a dynamic DNS service, which enables other computers to find you

even though you may be using a temporary, one-time IP address. This often

entails an extra charge, however, so check with your ISP.

Static IP addresses are considered somewhat less secure than dynamic IP

addresses, since they are easier to track for data mining purposes. However,

following safe Internet practices can help mitigate this potential problem and

keep your computer secure no matter what type of IP address you use.

DOMAIN NAME

A domain name is an identification string that defines a realm of

administrative autonomy, authority or control within the Internet. Domain

names are formed by the rules and procedures of the Domain Name

System (DNS). Any name registered in the DNS is a domain name. Domain

names are used in various networking contexts and application-specific

naming and addressing purposes. In general, a domain name represents

an Internet Protocol (IP) resource, such as a personal computer used to

access the Internet, a server computer hosting a web site, or the web site

itself or any other service communicated via the Internet. In 2015, 294 million

domain names had been registered.

WEB SEARCHG ENGINES

Search engines are programs that search documents for

specifiedkeywords and returns a list of the documents where the keywords

were found. A search engine is really a general class of programs, however,

the term is often used to specifically describe systems like Google, Bing and

Yahoo! Search that enable users to search for documents on the World Wide

Web.

EMAIL

Short for electronic mail, email (or e-mail) is defined as the transmission of

messages over communications networks. Typically the messages are notes

entered from the keyboard or electronic files stored on disk.

Most mainframes, minicomputers, and computer networks have an

email system.

Some electronic mail systems are confined to a single computer system or

network, but others have gateways to other computer systems,

enabling users to send electronic mail anywhere in the world. Companies that

are fully computerized make extensive use of e-mail because it is fast,

flexible, and reliable.

Typical Components of an Email System

Most e-mail systems include a rudimentary text editor for composing

messages, but many allow you to edit your messages using any editor you

want. Some systems will also provide basic formatting, including bold, italics,

font color and HTML. You can use the program to send the message to a

recipient by specifying the recipient's address. You can also send the same

message to several users at once. This is called broadcasting.

VOICE MAIL

Voicemail is a method of storing voice messages electronically for later

retrieval by intended recipients. Callers leave short messages that are stored

on digital media (or, in some older systems, on analog recording tape).

Originally, voicemail was developed for telephony as a means to prevent

missed calls, and also to facilitate call screening. In recent years, voicemail

has become integrated with theInternet, allowing users to receive incoming

messages on traditional computers as well as on tablets and mobile phones.

Microsoft Exchange is a popular platform for voicemail with desktop and

notebook computers. Users can play their voicemail messages either as

audio (MP3) or as text. In order to play a voicemail or read it as text, the user

simply clicks on an inbox item, just as would be done with an ordinary e-mail

message.