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Internet and Networking – Computer Awareness for Bank Exams

Internet


The Internet is a  global network  of interconnected network, enabling users  to share information along multiple channels. A computer  that  connects  to the Internet can  access information from a vast array of available servers  and other computers by moving information from them to the computer’s local memory. A majority of widely accessible information on the Internet  consists  of inter-linked  hypertext documents and other resources of the World Wide Web (WWW). Computer users typically manage sent and received information with web browsers; other software for users’ interface  with computer networks includes  specialised  programs for electronic mail, online chat,  file transfer and file sharing. The movement of information in the Internet  is achieved via  a system of interconnected computer  networks that share data by packet switching using the standardised Internet Protocol Suite (TCP/IP). It is a  “network of networks” that consists of millions of private and public, academic, business, and government networks  of local to global scope that are linked by copper  wires, fiber-optic  cables, wireless connections, and other technologies. It is really a way for computers to communicate and share informations. It is  a fast  developing net and is of outmost importance for public  sector undertakings, educational institutions, research  organisations  etc.

Services of Internet

E-mail ::
The internet enables user to exchange data/information and communicate via electronic media. E-mail messages are usually encoded in American Standard Code for Information Interchange (ASCII) text. A popular protocol for sending e-mail is Simple Mail Transfer  Protocol (SMTP) and for receiving it is  POP3.


Chat ::
It is the exchange of typed message by netizens. It enables netizens to ‘talk not vocal’ by typing and sending the messages back and forth. It has two modes—computer to telephone and computer to computer. Internet Relay Chart  (IRC) developed by  Jarkko  Oikarinen  in 1998.

Video Conferencing ::
A service that allows a group of users to exchange video information over the internet. It include an audio teleconference facility. Each participant’s computer must have a camera, microphone and earphones (or speaker).

Important Terms of  Internet

TCP/IP (Transmission Control Protocol/Internet Protocol) ::
This account is very useful in the sense that the members can have unlimited access. For membership of this account, UNIX operating system is needed which is loaded with TCP/IP software. In this account graphs, figures,  games, movies are available.


PPP (Point to Point Protocol) ::
It is a dial account which puts your computer directly on the internet. The computer will have its own host name and IP address. A modem is required for such connection which transmit the data 9600 bits per second.

WWW (World Wide Web) ::
It described as Wide Area Hypermedia Information initiative which aims to provide universal access to a large universe of documents. Mosaic programs is used to search the web. The operations of the web makes use of hypertext. It provides an integrated  view of the internet used by clients  and servers.

CNEB ::
It is one of the services communicated via the Internet. It is  a collection of inter connected documents and other  resources, linked by hyperlinks and URLs.

Gopher ::
All the available resources on the internet are shown by the Gopher in the form of menus. The concept  of Gopher  is based on the clients and servers.


WAIS ::
It is known as Wide Area Information Server. It maintains separate index for the contents of some selected documents. By pressing the name, WAIS provides a list of documents available in that index with similar keywords.

Mosaic ::
It is a program to cruise the internet. It can eliminate the needs of separate internet programs. It make the Internet available for  everyone.

Archie ::
It is a program which helps in looking for an information on the internet. It searches its database and informs about the files. It can be termed as global librarian which  automatically reaches to whole of the internet  services.

Hypertext ::
It is like a simple or regular text which can be written, edited and modified. Hypermedia is an advanced version of hypertext. It contains  several links to text, sounds, images etc.

Web Addresses (URLSs) ::
URL stands for Uniform Resource Locator. A web address start with the name of a protocol, which is called a HTTP (Hypertext Transfer Protocol). HTTP means  that  the resource in question will be found on  a web server.

Networking ::
Network is wade of communication with computers. A network means a  small group of ten-twelve personal computer  or it may also 64000  different types  of networks linked over INTERNET. The network of computers classify into LAN, MAN  and WAN.

Firewall ::
A firewall is a system  or group of systems  that  enforces an  access control policy between two networks.

Local Area Network (LAN)
It is a system in which computers are inter-connected and the geographical spread may be within a building to 1 kilometre. A number of terminals can be used in the whole building at various places with sharing means. All the terminals  are connected to a main computer called server.

Types of LAN

Star LAN :: 
A number of stations are connected to control station. The station passes information to the central station and then proceed it to the destination station. If one node of the network  fails,  it does  not affect the connectivity.

Ring LAN ::
Stations are connected by cables using point-to-point link. Network access is not under control of central station. Each station can pass data to its adjacent node. Data travels  through each node so failure in a single node cause failure of network.

Bus LAN ::
There is no repeater. Stations are common and single communication line. Data is sent in packets and related station picked up by it. Any fault diagnosis  is difficult.

Wide Area Network (WAN)
Network spread across countries. The network that brought the world on single platform. Usually use mainframe oriented systems. Use transmission channels such as co-axial cable or microwave.


Types of WAN

Public Networks ::
These networks are owned and run by Telecommunication Authorities. These are made available to an individual subscriber or an  organisation,  ie, PSTN,  PSDN, VAN,  ISDN.

Public Switched Telephone Networks (PSTN) ::
It is designed for telephone, which requires modem for data communication. It is used for FAX machine also. Its  features—low  speed transmission,  analog transmission,  less  bond width,  easy access,  cover almost every place.

Public Service Digital Network (PSDN) ::
It is  popular mode for connecting public and private mail system to have electronic mail services  with other firms. Its features—high reliable, high  quality communication, cost effective usage.

Value Added Network (VAN) ::
It provides Electronic Data Interchange (EDI) facility. The owner rent out the network to subscribers. Exchange of information like invoices, sale-purchase order, etc, is  done.

Integrated Services Digital Network (ISDN) ::
It is used for voice, video and data services. It uses digital transmission. It combines both circuit and packet switching.

Private Network ::
It provides services at various locations using private or leased circuits by using technology of its choice. It is mostly used to carry large volume of data at very high speed transmission. It uses Modem’s multiplexes and other  communication devices.

Metropolitan Area Network (MAN) ::
This type of network is spread over a city. Its main purpose is to share hardware and software resources by the various users. Its  example is cable TV network

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Mallikarjuna

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