Hello readers, welcome to the site of IndjobsPortal.in,Computer today has become an important part of our lives. infact today we are living in the age of Information Revolution which is much to be owed, to the ability of computer of desseminating information at an incredible speed. From education to entertainment and from communication to business, computers are present everywhere.
A computer network or data network is a telecommunications network that allows computers to exchange data. In computer networks, networked computing devices pass data to each other along data connections. Data is transferred in the form of packets. The connections between nodes are established using either cable media or wireless media. The best-known computer network is the Internet.In this section we are going to discuss about computer Networks, Internet and its components. which are given as below:
Computer Network Components-
* Computers and divices can be connected in different ways, the must typical topology is the star net work.
* Computers are divided into groups and connected directly to a special device called HUB.
* The network connecting components are the cables, which often determine the speed of LAN.
* Cables have a speed measure in bits per second which indicate how many bits can flow through the cable in one second.
* Eathernet cable have a speed of 10 MBPS and can thus carry 1.25 MB each second.
* A wireless network, cableless network where computers use radio signal to communicate, has usually a theoretical speed of 100 MBPS.
* When a LAN is connected to the internet, there is one, or sometime more than one, special computer called Gateway dedicated to this connection and and to keep relation with outside world.
* Firewall is a program in charge of rejecting unwanted incomming connection attempts and sometimes of forbidding unauthorised outgoing connections.
* Webserver is a program in charge of publishing web pages, the webserver offer the local web pages to users outside, answering to requests coming from external users.
- Common Termonology and Abbreviations Used In Computer
- General Awareness, Marketing And Computer awareness Questions
- General Knowledge Questions 2017
computer networks use the internet protocol (IP) address system, every network device is identified by an IP number composed of four numbers from 0 to 255 separated by dots(.) for example 126.96.36.199 is a valid IP Number. Usually LANs have private IP Numbers, using traditionally those stating with 10 (10.0.1.5), moreover every computer identified itself via the name “localhost” with address 127.0.0.1
Many incomming and outgoing connections can arive and leave a single computer at the same time. to kep corectly to track of all the connections, computer lets them in and out through different ports, according to the service they are asking or giving.
Human users often dislike numbers and prefer meaningful names, which can be more easily remembered. there fore many computers and divices have also an Internet name. these names have the special form subdomain. The domain choosen by the network’s owner to reflect the company name or to be easily remembered by web serface.The subdomain usually indicates the service offered by the computer.
Inside a computer network many communication programms are installed on Interanet computers to connect to the internet or even to the internal computers.
A web browser is a client program to navigate the WWW and retrieve web pages. It runs directly on the user’s computer and passes through the gateway at port 80 to reach outside web servers. It is one of the most vulnerable programs. since it is widely installed and often used by novice users.
A mail reader is a client program to send and retrieve e-mails. It runs directly on the user’s compueter and connect to the local mail-server, or sometimes to remote mail-servers. this is also a vulnerable programs, since it often used by novice users and since e-mail can carry attached files.
To communicate with the mailserver the mail reader uses special language, called protocols:
* Post office Protocol (POP) to retrieve e-mails at port 110.
* Simple Mail Transfer Protocol (SMTP) to send e-mails at port 25.
* Internet Mail Access Protocol (IMAP) is more modern protocol, which will become popular in next years, to retrieve and send e-mails.
Big internet proverder and large network usually have three different mail-servers, one each protocol, the POP server only for incoming e-mails, the SMTP server only for outgoing e-mail and the IMAP server for every connection using the new protocol.
World Wide Web-
the world wide web (WWW) born in mid 90s, is hudge collection of electronice documents, which are accessible from all over the inetrnet using a web browser. the two strengh of of the WWW are the hyperlinks, a system which allows the user to click on some keywords and access documents related to the chosen word, and the easy technical tools that let anybody build a set of web pages, called website.