Components of Information Technology

Computer – Commonly Operated Machine Particularly Used for Technology Education and Research

A computer is an electronic device that can perform activities automatically that involve in mathematical, logical, and graphical. It has the ability to store, retrieve, and process data. You can use a computer to type documents, send email, play games, and browse the Web.

          On the other hand a computer is a device that accepts information (in the form of digitized data) and manipulates it for some result based on a program or sequence of instructions on how the data is to be processed. Father of computer is Henry Babbage and Charles Babbage is called the "Grand Father" of the computer. The First mechanical computer designed by Charles Babbage was called Analytical Engine.

          Computer is an advanced electronic device that takes raw data as input from the user and processes these data under the control of set of instructions (called program) and gives the result (output) and saves output on to the storage devices for the future use. It can process both numerical and non-numerical (arithmetic and logical) calculations.

Characteristic of Computer-

SPEED:-  In general, no human being can compete to solving the complex computation, faster than computer It can perform in a few seconds.

ACCURACY:-  Since Computer is programmed, so whatever input we give it gives result with accurately.

STORAGE: - Computer can store mass storage of data. A computer can store and recall any amount of information because of its secondary storage capability.

Automatic:-  computers are automatic machines because once started on a job, they carry on until the job is finished, normally without any human assistance.

Multi programming or Versatility:- The computer can do many different things. It can accept information through various input-output devices, perform arithmetic and logic operations, and generate a variety of outputs.

Reliability:- The output generated by the computer is very reliable as long as the data is reliable.

Diligence:- A computer will never fail to perform its task due to hard work or laziness. 

Automation:- Once the instructions are fed into computer it works automatically without any human intervention.

No IQ : A  computers not a magical device. It possesses no intelligence of its own. Its IQ is zero. A computer can not take its own decision in this regard. 

No feeling: Computers have no feelings and no emotions because they are machines.

Limitations of computer-

• ·       Programmed by Human (No Self Intelligence)
• ·       No thinking capacity
• ·       Can’t self care
• ·       Can’t feel
• ·       No Decision-Making power
• ·       Need expertise
• ·        No learning power

Types of Computer on the Basis of function-

Analog Computer: - A device that processes infinitely varying signals, such as voltage or frequencies. Analog ( रेखीय ) computers are used to process analog data. Analog data is of continuous nature and which is not discrete or separate. Such type of data includes temperature, pressure, speed weight, voltage, depth etc. These quantities are continuous and having an infinite variety of values.

Ex-The Speedometer of a car measures speed, the change of temperature is measured by a Thermometer, the weight is measured by Weights machine.

Digital Computer:- A Digital Computer, works with digits to represent numerals, letters or other special symbols. In digital computer data flow in discrete from. Digital computer uses binary bit 0, 1 to represent the data. It can perform arithmetic operations as well as logical operations. The results of digital computers are more accurate than the results of analog computers.

Ex- Digital watch, Calculator

* Analog computers are faster than digital.

*Analog computers lack memory whereas digital computers store information.

* We can say that digital computers count and analog computers measures.

Hybrid Computer: - A hybrid computer is a combination of digital and analog computers. It combines the best features of both types of computers, i.e. It has the speed of analog computer and the memory and accuracy of digital computer. For example a petrol pump contains a processor that converts fuel flow measurements into quantity and price values. In hospital Intensive Care Unit (ICU), an analog device is used which measures patient's blood pressure and temperature etc, which are then converted and displayed in the form of digits. Hybrid computers for example are used for scientific calculations, in defense and radar systems.

 

Types of Computer on the Basis of Purpose: -

1- General Purpose Computer- PC, Laptop etc.

2- Special Purpose Computer- Designed to meet the need of some specific task. Ex- traffic lights control system, navigational system in an aircraft, weather forecasting, satellite launch / tracking, oil exploration, and in automotive industries, keeping time in a digital watch, or Robot helicopter.

Types of Computer on the Basis of Configuration/Size: -

Super Computer- Supercomputers are the most powerful computers in terms of performance and data processing. These are specialized and task specific computers used by large organizations. These computers are used for research and exploration purposes, like NASA uses supercomputers for launching space shuttles, controlling them and for space exploration purpose.

• The supercomputers are very expensive and very large in size. It can be accommodated in large air-conditioned rooms or entire building.
• The fastest Supercomputer in the world is Tihane-2A (China). And first supercomputer of India is PARAM 8000.
• India’s fastest super computer is PARAM YUVA 2(Old) latest Cray XC40(Supercomputer Education and Research Centre (SERC)).

Mainframe computer- Mainframes are not as powerful as supercomputers, but certainly they are quite expensive. Many large firms & government organizations uses Mainframes to run their business operations. Banks educational institutions & insurance companies, Airlines Companies, Railway etc use Mainframe Computer.

Ex - Fujitsu’s ICL VME, Hitachi’s Z800

Minicomputer- Minicomputers are used by small businesses & firms, Universities, Research Labs. Minicomputers are also called as “Midrange or Midsize Computers”.  It is capable of running programs in a higher level language, such as FORTRAN or BASIC. These computers are not designed for a single user i.e. minicomputer is multiuser computer on a single time. Individual departments of a large company or organizations use Mini-computers for specific purposes. For example, a production department can use Mini-computers for monitoring certain production process.

Ex- K-202, TI-990, SDS-92

Microcomputer- The micro-computers are widely used & the fastest growing computers. These computers are the cheapest among the other three types of computers. The Micro-computers are specially designed for general usage like entertainment, education and work purposes. Desktop computers, laptops, personal digital assistant (PDA), tablets & smart phones, Calculator are all types of microcomputers.

Information Technology-

Information Technology (IT) is a new technology applied to the creation, storage, selection, transformation and distribution of information of many kinds. It has been defined differently by different people. “It deals with the use of electronic computers and computer software to convert, store, protect, process, transmit and retrieve information, securely.

Components of IT- 

Impact of IT-

Block Diagram of Computer:- 

Input Unit/Device: This is the process of entering data and programs in to the computer system. An input device is any hardware device that sends data to a computer, allowing you to interact with the computer.

Example-

Keyboard, Mouse, Touch screen, Scanner, Light Pen, Microphone, Barcode Reader, Joystick, Biometric Device, OCR, OMR(Optical Mark Reader), MICR, Remote, Webcam, Touch Screen, Digital Camera.

Keyboard-   Keyboard is the most common and very popular input device which helps in inputting data to the computer. The layout of the keyboard is like that of traditional typewriter, although there are some additional keys provided for performing additional functions.

Mouse- Mouse is most popular pointing device. It is a very famous cursor-control device having a small palm size box with a round ball at its base which senses the movement of mouse and sends corresponding signals to CPU when the mouse buttons are pressed.

     Generally it has two buttons called left and right button and a wheel is present between the buttons. Mouse can be used to control the position of cursor on screen, but it cannot be used to enter text into the computer. 

Joystick- Joystick is also a pointing device which is used to move cursor position on a monitor screen. It is mainly used in Computer Aided Designing (CAD) and playing computer games. 

Scanner- Scanner is an input device which works more like a photocopy machine. It is used when some information is available on a paper and it is to be transferred to the hard disc of the computer for further manipulation. Scanner captures images from the source which are then converted into the digital form that can be stored on the disc. These images can be edited before they are printed. 

Microphone- Microphone is an input device to input sound that is then stored in digital form. The microphone is used for various applications like adding sound to a multimedia presentation or for mixing music.

Magnetic-Ink Character Recognition (MICR)- MICR input device is generally used in banks. 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). 

Bar Code Readers- 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 labeling goods, numbering the books etc. It may be a hand held scanner or may. 

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.

Optical character recognition (OCR)- OCR is the recognition of printed or written text characters by a computer.  It is widely used as a form of data entry from printed paper data records, whether passport documents, invoices, bank statements, computerized receipts, business cards, mail.  It is a common method of digitizing printed texts so that it can be electronically edited, searched, stored more compactly, displayed on-line, and used in machine processes such as machine translation, text-to-speech. 

Biometrics Device- Biometrics device is a technology of measuring and analyzing biological data.  It refers to technologies that measure and analyze human body characteristics, such as DNA, fingerprints, eye retinas and irises, voice patterns, facial patterns and hand measurements, vein of hand for authentication purposes.

 

Control Unit

This unit controls and coordinates the operations of all parts of computer.

Functions of this unit are:

• ·        It is responsible for controlling the transfer of data and instructions among other units of a computer.
• ·        It manages and coordinates all the units of the computer.
• ·        It obtains the instructions from the memory, interprets them, and directs the operation of the computer.
• ·        It communicates with Input/output devices for transfer of data or results from storage.
• ·        It does not store data.

ALU (Arithmetic Logic Unit)

This unit consists of two subsections namely

• Arithmetic section
• Logic Section

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.

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.

Functions of memory unit are:

• ·        It stores all the data and the instructions required for processing.
• ·        It stores intermediate results of processing.
• ·        It stores final results of processing before these results are released to an output device.
• ·        All inputs and outputs are transmitted through main memory.

Types of Storage:-

Primary Storage: - A Primary storage device (Main Memory or Internal Memory) is a medium that holds memory for short periods of time while a computer is running.  It has a much lower access time and faster performance. Random Access Memory (RAM) and cache are both examples of a primary storage device.

Main memory is connected to the central processing unit via a memory bus. It is actually two buses an address bus and a data bus. The CPU firstly sends a number through an address bus, a number called memory address that indicates the desired location of data. Then it reads or writes the data in the memory cells using the data bus.

ROM: - In computers, it is useful to have instructions that are used often, permanently stored inside the computer. ROM enables us to do this without losing the programs and data when the computer is powered down. Only the computer manufacturer can provide these programs income; once done, you cannot change it.

RAM: -RAM is another type of memory found inside computers. RAM is a volatile memory and requires power to keep the data accessible; if power is lost all data contained in memory lost. In the computer, RAM is the working memory.  Data can be read (retrieved) or written (stored) in RAM.

Cache Memory: - Cache is a type of memory that is relatively small, but can be accessed very quickly. The basic purpose of cache memory is to store program instructions that are frequently used by software during operation. Fast access to these instructions increases the overall speed of the software program.

Secondary Memory: - It is used for storing data and instructions permanently.  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. It is also used for carrying data from one computer to another. Secondary memory is not directly accessible to CPU. It is usually slower for read/write, cheaper and used in larger storage capacity.

Example: Hard disk, CD, DVD, Pen drive, etc.

Types of Secondary memory are:

·         Magnetic memory

·         Optical memory

Magnetic Memory

Magnetic memory uses the property of magnet for storing data. It is in use since first generations of computer. It contains data storing surface coated by magnetic oxide. Magnetic memory is further divided as: 

Magnetic Drum

Magnetic drum contains a metallic drum coated by magnetic oxide on the outer surface of the drum; data is stored in this surface. It was in use in first and second generations of computer.

Magnetic tape

Magnetic tape contains thin plastic ribbon; both side of the ribbon is used for storing data. The data storing side is coated by magnetic oxide. It is a sequential access memory. So, the data read/write speed is slower. It is mainly used for storing audio, video and back-up data.

Magnetic disk

Magnetic disk contains a circular disc made of metal or plastic. Both side of the disc is usually used for storing data. The disc is coated by magnetic oxide. The disc is divided into multiple concentric circles known as track. Tracks are further divided into small area known as sectors. Data are stored in sectors.

Example: Hard disk, 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 and can be 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.

Optical Memory

Optical memory uses light beam for its operation. It is developed in fourth generation of computer. It is mainly used for storing audio/video, backup as well as for carrying data. It requires optical drive for its operation. Its read/write speed is slower compared to hard disk and flash memories.

Example: CD, DVD

CD

It stands for Compact Disk. It has storage capacity of 700 MB or approximately 90 minutes of standard audio. CD contains hard circular plastic, single side of this plastic is coated by aluminum alloy. This alloy stores data. It is protected by additional thin plastic covering. CD required CD drive for its operation. Types of CD are:

CD-R- It is a blank CD in which data can be stored once. After storing data it is converted into CD-ROM.

CD-ROM- It cannot be erased or updated

CD-RW (Compact Disk-Rewritable)- It can be erased and used for multiple times.

DVD

It stands for Digital Versatile Disk. It has the storage capacity of 4.7GB to 17GB. Its shape and size is similar to CD but the difference in storage capacity is due to different chemical component and data is compressed before storing. It requires DVD drive for its operation. Read/write speed of DVD is slower than that of CD. Types of DVD are:

Ø     DVD-R

Ø     DVD-ROM

Ø     DVD-RW

Output Devices:-

Monitors-

Monitors, commonly called as Visual Display Unit (VDU) or Visual Display Terminal (Last Place), are the main output device of a computer. It forms images from tiny dots, called pixels that are arranged in a rectangular form. The sharpness of the image depends upon the number of pixels.

There are two kinds of viewing screen used for monitors.

• Cathode-Ray Tube (CRT)
• Flat- Panel Display

 Cathode-Ray Tube (CRT) Monitor

This technology used in most televisions and computer display screens. This monitor is large in size and its weight is also greater.CRT monitor has a issue that there are many dead pixels. Almost every CRT has a better viewing angle.

Flat-Panel Display Monitor

The flat-panel display refers to devices that have reduced volume, weight and power requirement in comparison to the CRT. You can hang them on walls or wear them on your wrists. Current uses of flat-panel displays include calculators, video games, monitors, laptop computer, graphics display.

LCD (Liquid-Crystal Device) - LCD is a flat display technology used in laptops, cell phones, calculators, digital cameras, and flat screen displays. The LCD is made of two glass sheets of a flexible polarizing material and a layer of liquid crystal solution between the two.

An electric current passed through the liquid causes the crystals to align so that light cannot pass through them. Each crystal, therefore, is like a shutter, either allowing light to pass through or blocking the light. This shutter along with the others provides the color which you want.

The LCD TV uses fluorescent lamps, and the LED TV uses LED (Light Emitting Diodes).

Contrast and Black level of the LED screen is better than the LCD screens because the liquid crystals cannot stop 100% of the backlight 

 LED displays consume less power. It is reported that they consume up to 40% less power than the LCD displays.

 LED displays do not use mercury (used in cathode lamps in LCD backlight) so they are environment friendly.

The size of Edge and RGB monitors is slight thinner than the LCD monitors while prices are slight higher.

Basically LED monitors are the LCD monitors with a LED backlight to power up the LCD panel. It means that LEDs are placed behind or around the LCD panel to enhance the luminosity and video definition of the monitor screen.

Printers

Printer is an output device, which is used to print information on paper.

There are two types of printers:

• Impact Printers
• Non-Impact Printers

Impact Printers

The impact printers print the characters by striking them on the ribbon which is then pressed on the paper.

Characteristics of Impact Printers are the following:

• Very low consumable costs
• Very noisy
• Useful for bulk printing due to low cost
• There is physical contact with the paper to produce an image

These printers are of two types

• Character printers
• Line printers

Character Printers

Character printers are the printers which print one character at a time.

These are further divided into two types:

• Dot Matrix Printer(DMP)
• Daisy Wheel

DOT MATRIX PRINTER

In the market one of the most popular printers is Dot Matrix Printer. These printers are popular because of their ease of printing and economical price. Each character printed is in form of pattern of dots and head consists of a Matrix of Pins of size (5*7, 7*9, 9*7 or 9*9) which come out to form a character that is why it is called Dot Matrix Printer.

Advantages

• Inexpensive
• Widely Used
• Other language characters can be printed

Disadvantages

• Slow Speed
• Poor Quality

DAISY WHEEL

Head is lying on a wheel and pins corresponding to characters are like petals of Daisy (flower name) that is why it is called Daisy Wheel Printer. These printers are generally used for word-processing in offices which require a few letters to be sent here and there with very nice quality.

Advantages

• More reliable than DMP
• Better quality
• The fonts of character can be easily changed

Disadvantages

• Slower than DMP
• Noisy
• More expensive than DMP

Line Printers

Line printers are the printers which print one line at a time..

Non-impact Printers

Non-impact printers print the characters without using ribbon. These printers print a complete page at a time so they are also called as Page Printers.

These printers are of two types

• Laser Printers
• Inkjet Printers

Characteristics of Non-impact Printers

• Faster than impact printers.
• They are not noisy.
• High quality.
• Support many fonts and different character size.

Laser Printers

These are non-impact page printers. They use laser lights to produce the dots needed to form the characters to be printed on a page.

ADVANTAGES

• Very high speed
• Very high quality output
• Give good graphics quality
• Support many fonts and different character size

DISADVANTAGES

·        Expensive.

·        Cannot be used to produce multiple copies of a document in a single printing.

Inkjet Printers

Inkjet printers are non-impact character printers based on a relatively new technology. They print characters by spraying small drops of ink onto paper. Inkjet printers produce high quality output with presentable features.

They make less noise because no hammering is done and these have many styles of printing modes available. Colour printing is also possible. Some models of Inkjet printers can produce multiple copies of printing also.

ADVANTAGES

• High quality printing
• More reliable

DISADVANTAGES

• Expensive as cost per page is high
• Slow as compared to laser printer

Software-

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. Software is a collection of instructions that enable the user to interact with a computer, its hardware, or perform tasks. Without software, computers would be useless.

There are two types of software

• System Software
• Application Software

System Software

The system software is collection of programs designed to operate, control, and extend the processing capabilities of the computer itself. These software products comprise (Bane Hue)of programs written in low-level languages which interact with the hardware at a very basic level. System software serves as the interface between hardware and the end users. Some examples of system software are Operating System, Compilers.

Features of system software are as follows:

• Close to system
• Fast in speed
• Difficult to design
• Difficult to understand
• Less interactive
• Difficult to manipulate
• Generally written in low-level language

DIFFERENT TYPES OF SYSTEM SOFTWARE 

1.           Operating System Software

2.           Language Translator 

3.           Utility Software

Operating system software

An Operating System is a program designed to run other programs on a computer. It provide interaction between user, hardware and other software of the computer. Operating systems are responsible for each and everything from the control and allocation of memory to input from external devices and output to computer display.

There various types of operating system are -

• ·                     General Purpose O.S
• ·                     Special Purpose O.S
• ·                     Single Use O.S
• ·                     Multi-User O.S
• ·                     Multi-Programming O.S
• ·                     Real Time O.S

Language Translator 

It is system software which convert the high level language to machine level language for the purpose of machine understanding.

The Machine can only understand the machine level language or binary language 0's & 1's. The language translator rectifies the errors within the program through different ways.

There are 3 types of language translator, they are as follows:-

·                     Compiler.- converts 3rd generation languages such as C++ into machine code all at once

·                     Interpreter. converts 3rd generation languages such as javascript into machine code one line at a time

·                     Assembler. converts assembly code into machine code

Utility Software: Utility Software is a kind of system software designed to help, analyze, configure, optimize and maintain the computer. A single piece of utility software is usually called a utility or tool.

If we are having any problem related to system then we can solve it through utility software.

For example - Antivirus: - Utility scan for computer virus.

                     

The following are the activities those are coming under the utility software are -

• ·                     Back-Up Recovery.
• ·                     Registry Cleaners.
• ·                     Disk Partitions. Etc
• ·                     Driver 

Application Software

Application software products are designed to satisfy a particular need of a particular environment. All software applications prepared in the computer lab can come under the category of Application software.

Application software may consist of a single program, such as a Microsoft's notepad for writing and editing simple text. It may also consist of a collection of programs, often called a software package, which work together to accomplish a task, such as a spreadsheet package.

Examples of Application software are following:

• Payroll Software
• Student Record Software
• Inventory Management Software
• Income Tax Software
• Railways Reservation Software
• Microsoft Office Suite Software
• Microsoft Word
• Microsoft Excel
• Microsoft Powerpoint

Features of application software are as follows:

• Close to user
• Easy to design
• More interactive
• Slow in speed
• Generally written in high-level language
• Easy to understand
• Easy to manipulate and use
• Bigger in size and requires large storage space

Form of Software:-

Shareware or trial software

Freeware

Open source software

BCD CODE-

In computing and electronics, it is a way to express each of decimal digits with a binary code.

EBCDIC (Extended Binary Coded Decimal Interchange Code)- In an EBCDIC code, each alphabetic or numeric character is represented with an 8-bit binary number (a string of eight 0's or 1's). It is an IBM code for representing character as number. It is widely used on large IBM computers. 256 possible characters (letters of the alphabet, numerals, and special characters) are defined as EBCDIC. 92 approx has been identified.

decimal value	hex value	Character
075	4B	.
076	4C	<
077	4D	(
078	4E	+
079	4F	|
090	5A	!
091	5B	$
092	5C	*
093	5D	)
094	5E	;
095	5F	¬
096	60	-
097	61	/
106	6A	¦
107	6B	,
108	6C	%
109	6D	_
110	6E	>
111	6F	?
121	79	`
122	7A	:
123	7B	#
124	7C	@
125	7D	'
126	7E	=
127	7F	"
129	81	a
130	82	B
131	83	C
132	84	D
133	85	E
134	86	F
135	87	G
136	88	H
137	89	I
145	91	J
146	92	K
147	93	L
148	94	M
149	95	N
150	96	O
151	97	P
152	98	Q
153	99	R
161	A1	~
162	A2	S
163	A3	T
164	A4	U
165	A5	V
166	A6	W
167	A7	X
168	A8	Y
169	A9	Z
192	C0	{
193	C1	A
194	C2	B
195	C3	C
196	C4	D
197	C5	E
198	C6	F
199	C7	G
200	C8	H
201	C9	I
208	D0	}
209	D1	J
210	D2	K
211	D3	L
212	D4	M
213	D5	N
214	D6	O
215	D7	P
216	D8	Q
217	D9	R
224	E0	\
226	E2	S
227	E3	T
228	E4	U
229	E5	V
230	E6	W
231	E7	X
232	E8	Y
233	E9	Z
240	F0	0
241	F1	1
242	F2	2
243	F3	3
244	F4	4
245	F5	5
246	F6	6
247	F7	7
248	F8	8
249	F9	9

ASCII CODE-

ASCII stands for American Standard Code for Information Interchange. Computers can only understand numbers, so an ASCII code is the numerical representation of a character such as 'a' or '@' . ASCII was developed a long time ago and now the non-printing characters are rarely used for their original purpose.

Personal Area Network-

A personal area network, or PAN, is a computer network organized around an individual person within a single building. This could be inside a small office or residence. A typical PAN would include one or more computers, telephones, peripheral devices, video game consoles and other personal entertainment devices.

This type of network provides great flexibility. For example, it allows you to:

• Send a document to the printer in the office upstairs while you are sitting on the couch with your laptop.
• Upload the photo from your cell phone to your desktop computer.
• Watch movies from an online streaming service to your TV.

Local Area Network- Local Area Networking is used primarily in small areas such as schools, hospitals and office buildings. Local Area Networking, is one of the older types of networks. A LAN is very useful for sharing resources, such as data storage and printers. The smallest LAN may only use two computers, while larger LANs can accommodate thousands of computers. A LAN typically relies mostly on wired connections for increased speed and security, but wireless connections can also be part of a LAN. High speed and relatively low cost are the defining characteristics of LANs.

     LANs are typically used for single sites where people need to share resources among themselves but not with the rest of the outside world. If a local area network, or LAN, is entirely wireless, it is referred to as a wireless local area network, or WLAN.

Metropolitan Area Network-

A metropolitan area network, or MAN, consists of a computer network across an entire city, college campus or small region. A MAN is larger than a LAN, which is typically limited to a single building or site. is often used to connect several LANs together to form a bigger network. When this type of network is specifically designed for a college campus, it is sometimes referred to as a campus area network, or CAN.

Wide Area Network-

A wide area network, or WAN, occupies a very large area, such as an entire country or the entire world. A WAN can contain multiple smaller networks, such as LANs or MANs. The Internet is the best-known example of a public WAN. Wide Area Networks use optic fibre  as their communication medium. 

Oovoo, MegaMeeting, Click Meeting, RHUB, Adobe Connect, CISCO WEB EX, Citrix Go To Meeting, Fuze

Network Topology-

 A topology is a description of the arrangement of a network, including its nodes and connecting lines. The pattern of the interconnections between computers in a network is called network topology.

Bus Topology-  In networking a bus is the central cable,   that connects all devices on a local-area network (LAN). Bus networks are relatively inexpensive and easy to install for small networks. It transmits data only in one direction. Every device is connected to a single cable.

 

Advantages of Bus Topology

    1.  It is cost effective.

  2 Cable required is least compared to other network topology.

    3.  Used in small networks.

    4.  It is easy to understand.

            Disadvantages of Bus Topology

    1.  Cables fails then whole network fails.

   2. If network traffic is heavy or nodes are more the performance of the network decreases.

                                                                    3.  Cable has a limited length.

RING Topology- All of the nodes are connected in a closed loop. In ring topology, the computers in the network are connected in a circular fashion, and the data travels in one direction. Each computer is directly connected to the next computer.

 

Advantages of Ring Topology

  1. Transmitting network is not affected by high traffic or by adding more nodes, as only the nodes having tokens can transmit data.

   2. Cheap to install and expand

   3. If there's a problem in the network, it    is easy to find out which connection is defective.

Disadvantages of Ring Topology

1.          Troubleshooting is difficult in ring topology.

2.          Adding or deleting the computers disturbs the network activity.

3.          Failure of one computer disturbs the whole network.

STAR Topology

In star topology, each computer is connected to a central hub using a point-to-point connection. In this type of topology all the computers are connected to a single hub through a cable. The central hub can be a computer server that manages the network, or it can be a much simpler device that only makes the connections between computers over the network possible.

Advantages of Star Topology

1.   Fast performance with few nodes and low network traffic.

2.      Hub can be upgraded easily.

3.      Easy to troubleshoot.

4.    Easy to setup new node and modify.

5.    Only that node is affected which has failed rest of the nodes can work smoothly.

Disadvantages of Star Topology

1.   Cost of installation is high.

2.   Expensive to use.

3.  If the hub is affected then the whole network is stopped because all the                                                                                      nodes depend on the hub.

                                                                               4.   Performance is based on the hub that                                                                                  is it depends on its capacity.

MESH Topology

It is a point-to-point connection to other nodes or devices. Traffic is carried only between two devices or nodes to which it is connected.

Advantages of Mesh Topology

1. Each connection can carry its own data load.

2.  Fault is diagnosed easily.

3.  Provides security and privacy.

Disadvantages of Mesh Topology

1. Installation and configuration is difficult.

2.    Cabling cost is more.

3.    Bulk wiring is required.