CSCI intenet and web

access provider (ISP)

A company that provides its clients with a point of presence on the Internet so that they can take advantage of its resources. Typically, these companies charge a monthly usage fee and provide last-mile connections that will bring Internet access to the home. For example, Comcast serves as an access provider that gives cable Internet service to its patrons.

domain name server

A computer on a network that hosts a large database of domain names and their associated IP addresses and enables other computers on its' network to resolve domain names into IP addresses for transmission across the Internet

spider

A program that a search engine uses to scan the web and find new sites to index. The spider "crawls" the web following links from page to page adding them to the search engine database.

search engine

A program that takes a search query and uses it to return web pages in its database that meet the criteria spelled out in the query. What makes search engines unique is that their database is built by computer programs and not by people. Thus, the sites you receive from a search engine like google have not been evaluated by humans in any way. However, computers can index sites must faster than humans and thus google has approximately 6 billion pages in its database.

directory

A search tool that allows users to find web pages by browsing through categories that start out general and become more and more specific. The pages in a directory have been categorized and loosely evaluated by people and tend to be a bit better than random search engine hits. However, people are slower to index things than computers, and thus, directories have far fewer pages in their index.

virtual library

A search tool that makes use of a database of web sites that have been evaluated by experts. Thus, the results of a virtual library tend to be of better quality than those returned by most other tools. However, expert evaluation of pages takes a long time and virtual libraries correspondingly index fewer pages than other search tools.

web page

A single electronic document on the Internet. Typically, web pages are encoded in HTML and are designed to be downloaded and viewed in a web browser

packet

A small collection of data that has been packaged for transmission across the Internet. A packet has a header that indicates the source and destination addresses for the packet as well as information that allows data spread over multiple packets, such as a file, to be reassembled at the destination.

router

A special purpose computer whose sole function is to look at the IP addresses of incoming packets and to direct those packets along the correct output wire leading to the packet's destination. A router continually updates its' input and output tables to adjust for changing network conditions and is never guaranteed to send two packets along exactly the same route or to use the most efficient route.

search query

A string consisting of keywords that a user wants to find on the web. A search engine takes a search query and uses its internal rules to return a list of web pages that fit the keywords and other criteria in the query. Each page that satisfies the query is called a hit.

internet

A worldwide collection of computer networks that agree to communicate using specific protocols, the most basic being Internet Protocol and Transmission Control Protocol (TCP-IP), and the services provided by those networks.

plug in

Browser programmers found it difficult to keep up to date with all the different types of media people wanted to offer on their web path, and thus, decided to create a general interface (API) through which developers can add functionality to the browser. A Plug-In is a small program that interfaces with this API and tells the browser how to deal with new media types.

URL

The address of a page on the web. A URL or Uniform Resource Locator consists of a protocol (typically http://) followed by the domain name and file location (path and file name) of the actual page.

ip address

The numerical address of a computer on the Internet ad defined by the Internet Protocol(IP). An IP address takes the form of a dotted quad: four numbers between 0 and 255 separated by periods. For example, 210.15.96.5 is a valid IP address whereas 10.288.4.111 is not.

domain name

This is the human readable form of an IP address and provides a convenient way of accessing computers on the Internet. The domain name is actually translated to an IP address that computers can understand by a domain name server.

spam

Unsolicited commercial email that is sent in bulk to a collection of addresses culled from the Internet and company databases. It gets its name from the well know meat product courtesy of a connection drawn by a skit from the british comedy troupe Monty Python.

WAN (wide area network)

any network that connects geographically distant computers. For example, a WAN could connect all the LANs together across a college campus or connect a large company's computers around the world.

LAN (local area network)

any network that is geographically limited in scope. Initially LANs were limited by the maximum distance an ethernet cable could run without excessive signal degradation, but now they are usually limited to buildings, building floors, or single rooms.

web browser

computer program that fetches and then renders a web page for viewing by a computer user. This can be a complicated process as many browsers can support different types of media and allow for pages rich in content. However, because it is the browser that renders a web page, a page may look drastically different in different browsers. Some browsers are even designed to render pages in a handicapped accessible format.

meta search engine

searches through the results returned by several other search engines and returns a composite list of recommended pages. For example, a search for sharks on a meta-search engine might return the first 10hits from google, the first 10 from bing, and the top five from ask.

modem

short for modulator-demodulator and is device that allows computer information to travel across different types of telecommunication lines. For example, a cable modem will provide broad band Internet through one's television cable and a phone modem will provide dial-up access.