The most widely used service on the Internet is electronic mail. A user can send a message to a person on the other side of the world in a matter of minutes using this facility. In order to use e-mail, a user requires a mailing program and an address e.g. J.Smith@man.ac.uk. The text prior to @ identifies the user (user name), the portion of text after @ specifies the address of the site of the computer system where the mail account is held. An e-mail address is provided by a network supervisor or an Internet service provider.
The applications of e-mail, are, perhaps underestimated. A facility which e-mail provides is the ability to send a file with a message in the form of an attachment. For example, two groups working on a single project proposal may send copies of their work as the original wordprocessed file attached to an e-mail message. The message will be automatically sent with the e-mail message and the recipient will receive a copy of the file with the e-mail message. The recipient may then open and work on the file just as if it had been received on a floppy disc. This paper was sent to the FIP office as an attachment to an e-mail message. This is a powerful facility and any type of file (text, graphic, sound etc.) may be sent as an attachment.
Messages may be sent either to a single person or a group of people. A list of e-mail addresses may be constructed enabling a message to be sent to hundreds or even thousands of users. Modern e-mail programs will operate continuously and in the background and instantly alert the user when a message arrives. Commonly used e-mail programs include Pegasus Mail and Eudora, both of which are available for Macintosh and Windowsbased computer systems.
E-mail may also be used to form a discussion group in the form of a mailing list. A mailing list may be considered as a special e-mail address which forwards a copy of any messages it receives to those people who have chosen to 'subscribe' to the mailing list. If a subscriber sends a message to that particular e-mail address it will be forwarded to everyone who has subscribed to the list. It is, therefore, a useful means of disseminating information to a particular group of people. Mailing lists are often moderated. In these cases messages are checked for suitability before distribution to the subscribers of the mailing list.
Using the Internet it is possible to use another computer (remote computer), on the other side of the world, as if it was located in the next room. Provided a user has an account on the remote computer, a service known as telnet may be used to access and work on the computer. A user connects to the remote computer by calling its address. Once connected to the remote computer a user will be asked for identification by entering a username (called a userid), and to confirm the username with a password. The local computer effectively becomes a terminal (the remote computer does all the work and the user's computer becomes just a monitor and keyboard). A program such as NCSA Telnet is required on the host computer to be able to utilise this service. Many public services may be accessed via telnet e.g. the Electronic Yellow Pages.
One of the most powerful services on the network is the ability to transfer files to and from a remote computer using FTP (file transfer protocol). It is the main way in which software is distributed on the Internet. The service enables a user to connect to many servers around the world and to download (transfer files to the host computer) and upload (send files to the remote computer). There is an abundance of software available from several sites around the world, much of it excellent and free. Any conceivable type of file is available including information files, graphics files, word processing programs, graphic programs, and database programs.
Some FTP servers require the entry of a username and password, however the majority are anonymous FTP servers and allow access to the general public. There are thousands of FTP servers on the Internet. To connect to an anonymous FTP server the username 'anonymous' is used and the user's e-mail address is entered as a password. Once connected to the remote computer, a listing of directories and files is presented. There are several free client programs available to enable FTP file transfers e.g. Fetch, Xferit, and Anarchie for the Macintosh. The process of file transfer is, again, simple and transparent on Macintosh and Microsoft Windowsbased systems where the downloading of a file is usually a simple matter of double clicking on a particular file using the mouse.
Usenet is one of the most popular facilities on the network. It is not actually a network but a collection of discussion groups, usually called newsgroups. There are literally thousands of newsgroups specialising in virtually any subject and including areas such as pharmacy, medicine and specialised areas of science. Messages are sent to newsgroups in the form of an e-mail message, each message being referred to as an article or posting. In order to read newsgroups a user must first connect to a news server (the address of which is provided by a network supervisor or an Internet service provider) using a special type of client program called a newsreader. Usenet is a powerful forum for communicating with special interest groups. For example, a researcher may have a specific question on polymer science. A question may be sent to the newsgroup sci.polymers. This message will then be circulated world-wide to that particular newsgroup so that a question or comment posted in the UK may be read by a researcher in Australia. If a person reading an article wishes to respond then this is usually done by sending a response to the newsgroup, or, alternatively, an e-mail message may be sent to the sender of the original question. There are several programs that enable computers to access newsgroups, and these include Nuntius and NewsWatcher for the Macintosh.
A facility that may occasionally prove useful is the 'Talk' facility. A user on a host computer enters the address of a user on a remote computer who is subsequently notified that someone is trying to 'talk'. If there is a user on the remote computer and that person wishes to communicate, then an appropriate 'Talk' program is launched and the users may communicate over the Internet. Both monitors will split into two halves so that whatever the host user types on the top part of the screen appears on the remote users lower half of the screen. Thus two Internet users on the opposite sides of the world may communicate in real time. Problems may occur when the Internet is busy when there may be a delay of a few seconds before text is transmitted. 'Talk' software is available for most personal computers.
Gophers are servers that enable access to many of the information resources on the Internet using a user friendly interface. When running a Gopher client program on a host computer a user is presented with a menu. The user selects a file using the computer mouse and the Gopher will then obtain the selected file and display it on the monitor. A menu item may be a piece of software, in which case it is copied to the host's computer. A menu item may also lead to the menu of another Gopher server. Items on a Gopher menu may refer to files on several different computers, however, the process of file retrieval is transparent to the user. Gopher servers are accessed using client software such as Turbogopher on the Macintosh. Gopher servers are found in many universities, companies and organisations though they are likely to be superseded by Web servers in the future.
The World Wide Web (usually referred to simply as the Web or W3) is probably the most powerful and simplest method of providing and retrieving information on the Internet. The Web was designed to offer a user friendly and consistent interface to the vast resources on the Internet. Information from a Web server is retrieved using a program called a browser (client program). The browser provides a very simple user interface. Information is downloaded in the form of a file which is known as a page. A page can be of any length, with different parts of the document being accessed by scrolling (using a mouse to move to different parts of the page). Within a document there is usually text, however other forms of data may also be present such as high resolution graphics, sound clips, and even movie clips. The Web is often described as a hypermedia system because of the capabilities of displaying these different forms of data.
The main feature of the Web that makes it such a powerful tool for accessing information is the use of hypertext links. Certain words and phrases (often keywords) are highlighted within a Web page. These are known as hypertext links. Clicking a mouse on one of these highlighted pieces of text will result in another page being downloaded (Fig. 1). In this way information can be retrieved following logical hypertext links. Moving around the Web in this fashion is often termed 'navigating'. For example an article on Pharmacy in the UK may contain a list of the schools of pharmacy which are highlighted in the text. To obtain further information on any school the highlighted text would be clicked and a new file would be downloaded with the appropriate information on that school. A series of Web pages has been set up at the University of Manchester, called PharmWeb, which provides a starting point for accessing other pharmacy resources on the Internet.
One of the advantages of using a Web browser is that these programs usually allow a user to easily access other Internet resources such as Usenet newsgroups, FTP, and gopher servers in addition to Web servers. The Web is thus designed to organise and integrate all the information on the Internet as a set of hypertext links. Information may be retrieved and displayed using keyword searches.
Fig. 1 Schematic diagram indicating how information is retrieved using hypertext link on the World Wide Web. Each page of information is linked to another page by clicking the computer mouse on a highlighted hypertext link. A page of information may be of any length. If the length is greater the size of the computer monitor then different parts of the page my be accessed by scrolling. A page may contain a mixture of text, sound, images, and video clips.
The starting point on the Web is usually a home page. A home page is typically an index to other resources (pages) and is usually configured to be useful to the people who wrote the particular Web browser, however home pages can easily be changed by a user. Moving around the Web is intuitive and a desired resource may be found by clicking on several hypertext links. However, occasionally a user may be given the address of a page to download. The address of a resource on the Web is known as its URL (uniform resource locator). URL's look daunting, but in fact provide information to enable the browser to find a particular resource (it should be noted that URL's are case sensitive). An example of a URL is 'http://www.mcc.ac.uk/pharmweb/'. URLs are rarely used since information is usually relatively easy to find using hypertext links. Web browsers such as NCSA Mosaic and Mosaic Netscape are available for both the Macintosh and Microsoft Windows computer systems.Top of Page