COMPUTING SCIENCE

CLIENT/SERVER

Client/Server

Client/Server is a network where there are two levels of computers: servers and clients.


The server stores and manages access to files and data on a file server which means that multiple computers can connect together and sharte specific information and files. There may also be a print server which manages printing on the network by storing a queue of files to be printed.

Servers

•Stores programs and data files that can be accessed by the client stations.

•Users log on to the network with a user name and password.

•A list of users and passwords is kept on the server along with the user’s files.

•When the user loads a file from their user area the file will be sent from the server’s hard drive to the client station.

•After the user has edited the file and saves it to their user area, the file is sent back to the server and stored on the hard drive.

•Software on the server will ensure that only the user has access to their files and they are kept secure.

Client

•The client station runs programs with its own processor but has to contact the server for access to any files or shared resources.

•Shared resources can include printers, CD-ROMs, a database or access to the Internet.

Browsers

•To access the information on the www you need a client browser application.

•A browser is a program that allows a user to

read and navigate web pages.

•The browser has forwards and backwards buttons that allow the user to navigate ahead, or back to pages that were previously viewed.

•Two of the most common browsers are Chrome and Internet Explorer.

Search Engines

•Websites such as Yahoo and Google include a search engine that regularly runs programs called web crawlers to gather information about what pages are on the internet. When the web crawler comes across a document it sends the URL along with extracts of the content back to the site, where it is stored on a database.

•Searches the database for words that match your entry.

•Advanced searches can include operators such as AND and OR to help narrow the search.

•The results of the search are placed on a web page that is composed of hyperlinks and brief extracts from the original web page.

•To visit the actual page all you have to do is click on the hyperlink.

Economic factors leading to the development of computer networks

•Falling cost of telecommunication technologies and services

•Shared access to expensive equipment

•Geographic spread of organisation

•Demand for up-to-date information