Wireless Networking

Wireless network refers to any type of computer network that is wireless, and is commonly associated with a telecommunications network whose interconnections between nodes are implemented without the use of wires. Wireless telecommunications networks are generally implemented with some type of remote information transmission system that uses electromagnetic waves, such as radio waves, for the carrier and this implementation usually takes place at the physical level or "layer" of the network.

Contents

1.    Types of wireless connections

·       Wireless PAN

·       Wireless LAN

·       Wireless MAN

·       Wireless WAN

·       Mobile Devices networks

2.    Uses

3.    Environmental concerns and health hazard

4.    See also

5.    References

6.    Further reading

7.    External links

Wireless LAN

          A wireless local area network (WLAN) links two or more devices using a wireless distribution method (typically spread-spectrum or OFDM radio), and usually providing a connection through an access point to the wider internet. This gives users the mobility to move around within a local coverage area and still be connected to the network.

Wireless WAN

          Wireless wide area   networks are wireless networks that typically cover large outdoor areas. These networks can be used to connect branch offices of business or as a public internet access system. They are usually deployed on the 2.4 GHz band. A typical system contains base station gateways, access points and wireless bridging relays. Other configurations are mesh systems where each access point acts as a relay also. When combined with renewable energy systems such as photo-voltaic solar panels or wind systems they can be stand alone systems.

Types of Networking

One way to categorize the different types of computer network designs is by their scope or scale. For historical reasons, the networking industry refers to nearly every type of design as some kind of area network. Common examples of area network types are:

1.    LAN - Local Area Network

2.    WLAN - Wireless Local Area Network

3.    WAN - Wide Area Network

4.    MAN - Metropolitan Area Network

5.    SAN - Storage Area Network, System Area Network, Server Area Network, or sometimes Small Area Network

6.    CAN - Campus Area Network, Controller Area Network, or sometimes Cluster Area Network

7.    PAN - Personal Area Network

8.    DAN - Desk Area Network

LAN and WAN merged over many years of technology evolution

LAN - Local Area Network

A LAN connects network devices over a relatively short distance. A networked office building, school, or home usually contains a single LAN, though sometimes one building will contain a few small LANs (perhaps one per room), and occasionally a LAN will span a group of nearby buildings. In TCP/IP networking, a LAN is often but not always implemented as a single IP subnet

 

WAN - Wide Area Network

A WAN differs from a LAN in several important ways. Most WANs (like the Internet) are not owned by any one organization but rather exist under collective or distributed ownership and management. WANs tend to use technology like ATM, Frame Relay and X.25 for connectivity over the longer distances.

Defination of Computer Networking

A computer network is a system in which computers are connected to share information and resources. The connection can be done as peer-to-peer or client/server. This web site reviews the techniques you can use to set up and possibly manage a network for home or a small business.

A computer network is a collection of computers and a device interconnected by communications channels that facilitate communications among users and allows users to share resources. Networks may be classified according to a wide variety of characteristics. A computer network allows sharing of resources and information among interconnected devices.

Computer networks are interconnections of many computers. They share resources such as electronic mail, bulletin boards, and access to unique databases. Think of them as information highways for data. Networks are changing the computing paradigm from "number-crunching" to communicating. They have spawned industries such as the online industry, a collection of organizations providing information and communication services to remote customers via dial-up modems. In a computer network the individual stations, called "nodes," may be computers, terminals, or communication units of various kinds. Networks that are contained within a building or small geographical area are called local-area networks, or LANs. Below are articles on computer networking and guides to help in networking computers.

Computer Hardware, Software and Memory

Computer Hardware, Software and Memory

Computer Hardware and Software

          Computer system is generally divided into two parts: Hardware and Software.

1.    Hardware: - Hardware refers to the physical parts of the computer like CPU, Monitor, Printer etc. which can be touched and felt.

2.    Software: - Software is a group of programs which make computers work. The software tells the computer what to do and how to do.

          The Software are further divided into three major groups.

a)    Application Software: - It is a group of programs designed to solve particular problem e.g. word processing, spreadsheet, multimedia and presentation, database etc.

b)    System Software: - It is a set of programs which helps user to communicate with hardware e.g. Operating System, Assembler, Compiler, Interpreter etc.

c)    Utility Software: - It provides services for developing and debugging computer programs. e.g. Norton utilities, PC Tools etc.

Computer Memory

          The memory is the storage space in the computer system. It is the capacity of computer to store data and information. There are two types of memory: Primary memory and Secondary memory.

Primary memory

          It is also called Internal or Main Memory. RAM and ROM are the type of Primary memory.

RAM: -      Ram stands for Random Access Memory. It is the most commonly used memory. But, it is volatile memory. So, it needs regular supply of power to hold its content.

ROM: -      ROM stands for Read Only Memory. It is only for reading. It is the permanent memory. So, it holds the data even after the computer is switched off.

Secondary memory

          The secondary memory is used to store data and information for later use. They are also called Mass Storage or Auxiliary Memory because they can store huge data and information for longer duration of time.

          Secondary memory is installed in the computer from magnetic disks such as Hard disk, Floppy disk etc., Optical Disks such as CD-ROM, DVDs, etc. or electronic storage device like pen drive.

Output Device

Output Devices

          The output devices are the hardwares which accept result from the primary memory and supply it to the users or store it to secondary storage device for future use. They are mainly used for the output of the processed information.

          There are two types of output devices:

       i.            Soft Copy Output Devices

    ii.            Hard Copy Output Devices

Soft Copy Output Devices:

          These types of devices produce temporary output, the output that can only be seen but cannot be touched or felt. The commonly used softcopy output devices are CRT (Cathode ray Tube) monitor and Flat Panel Display.

Monitors

          The monitor is one of the most common output devices. It displays character and graphics.

1.    CRT Monitors

CRT Monitor is named so, because it uses large vacuum tube called Cathode Ray Tube (CRT). It looks like a common Television screen.

The CRT monitors are relatively bigger in size than other monitors but it is cheaper.

2.    LCD monitors

It is a type of flat-panel monitor. LCD monitors use a special kind of Liquid Crystal for Display. LCD monitors are comparatively light weight and portable monitors but they are expensive.

Hard Copy Output Devices:

          These types of output devices produce permanent output in printed or plotted form. The output can be touched or felt.

          The most commonly used hard copy output devices are printers and plotters.

Printer

          The printer is on of the most common output devices. It provides data, programs, texts and other results in a permanent readable form i.e. sheet of paper. The output produced from a printer is also known as hard copy output.

          Depending on their speed and approach of printing, printers can be classified as character printers, line printers and page printers. But commonly printers are classified into two types Impact and Non-Impact.

1.    Impact Printers

Impact printers include all printers that printers that work by striking on ink ribbon, for example, daisy-wheel, dot-matrix, and line printers. They are nosier than Non-Impact printers. Impact printers use typewriter approach of printing where letters are printed on papers through hitting of keys against paper and inked ribbon.

2.    Non-Impact Printers

Non-Impact printers include laser printers, ink jet printers and thermal printers. They are quite printers because they don't strike on the paper to form characters.

Input Device

Input Devices

          These devices are used to input data and program to the computer. These are the parts of computer through which data or instructions are given to computer for processing purpose. Some of the popular input devices are:

1.    keyboard

A keyboard is the primary input device through which data or instructions are entered into the computer. Most keyboards use a QWERTY layout. The layout is called QWERTY because such keyboard has those keys as the first six letters on the top of alphabetic line of keyboard. The most commonly used keyboard is 101 key keyboard developed by IBM. Nowadays there are enhanced or extended keyboards with at least 103 keys.

2.    Mouse

A mouse is a small input device which is used for pointing or drawing. It is connected to the computer by a small cable. As we move the mouse across the flat surface, the mouse pointer or cursor moves across the screen. Once the mouse pointer is in the desired location, we can press the mouse buttons to perform some operation.

A mouse is one of the most important and popular input devices for graphical user interface such as Apple/Macintosh and windows in which we can perform various complex operations with simple mouse clicks.

3.    Digital Camera

A digital camera can be used to input images into the computer. It takes a still photograph, stores it and then sends that photo or image as digital input to the computer. The computer stores those images in the form of digital files.

4.    Joystick

A joystick is pointing devices, used mostly for playing games on a computer. The joystick has a rectangular plastic base which is attached to a vertical stem. Control buttons are located on the base or to the top of stem. The stem can be moved to all directions to control the movement of an object on the screen depending on the type of application software being used.

Generation of Computers

Computer Generation

          The evolution of modern digital computer is often divided into generation. Evolution of modern computer is classified into five generations based on their speed, capacity, and reliability, technology used and programming languages.

First Generation Computer (1946-1958)

          The first generation computers were developed during 1946 to 1958. They used vacuum tubes and valves as the memory devices. They were large in size, very slow in speed, had very low capacity but were very expensive. They consumed a lot of power and produced a lot of heat. They used machine language programs. This made programming extremely difficult and time consuming.

Second Generation of Computer (1959-1964)

          The second generation computers were developed during 1959-1964. They used transistors as the electronic circuits. Second generations of computers were faster, more reliable, easier to operate, less expensive, smaller, required less electricity than of the first generation computers. The used Assembly language and the high level languages such as COBOL, ALGOL, FORTRAN etc.

Third Generation of Computer (1965-1974)

          The third generation computers were developed during 1965 to 1974. They used integrated circuit (IC) as electronic circuit. IC circuit consists of a large number of electronic components placed on a single silicon chip by a photolithography process. Jack Kilby developed the IC in 1958.

         

          This new technology made the third generation computers more reliable, faster, smaller, easier to operate, high capacity, less expensive than previous generation computers. Third generation computers included the use of an operating system for automatic processing and multi programming.

Fourth Generation of Computer (1975-1990)

          The fourth generation computers were developed during 1975 to 1990. The present day computers are included in this generation. They use large scale integrated circuit (LSI) and very large scale integrated circuit (VLSI) known as microprocessor chip as electronic circuits. In this generation, the use of microprocessor made computer very fast, capable of very high memory, small in size and less expensive than previous computers. Fourth generation computer used graphical devices and language interfaces to graphics system.

Fifth Generation of Computer (1991-incomplete)

The fifth generation computers were developed after 1991 and still moving towards the advanced technologies such as Artificial intelligence, very high speed, parallel processing etc.

          Fifth generation computers combine hardware and software to produce artificial intelligence (AI). They are able to process non-numerical information such as picture and graphs and are able to understand natural languages. They incorporate Ultra Large Scale Integration (ULSI).