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4.2 Other access methods

More efficient access services are becoming very popular today. Among them are gopher, WWW, mosaic, and WAIS. We give an overview to clarify terms, but for exact usage, see your local user's guide.

ARCHIE

Archie is a tool for finding the location of documents on ftp servers. It is designed for use when one knows only the file name or a part of it, but not the machine it resides on. You need to login to an Archie Server, usually the username is archie. A list of contents from different servers, usually quite large, is scanned for the specified file name. The server and directories, where the file(s) can be found, are the results of this search. Therefore, this search may take some time. The search is not online, the data bases are regularly updated, but very new entries may not be found.

GOPHER

Gopher can be regarded as a network of machines. In the so--called gopherspace, the machines can create pointers or links to other machines, such that an entry can be on any other machine in the net. This saves space on local machines and avoids unnecessary, duplicate copies. With Gopher, the access service VERONICA makes it easier to find documents, similar to Archie for ftp.

WAIS (Wide Area Information Servers) is another access tool. The main advantage of WAIS is that it can search in different data bases (with different access methods) with a single command language. Another of its features is contents--oriented search.

WWW

World Wide Web creates online connections to source documents in the net. It enables one to exchange multimedia documents like pictures and sounds and has a hypertext format, where one can jump to other topics by selecting keywords of the current text (like in the Windows help system). WWW needs so--called URLs (Universal Resource Locators) to find the host machines and document paths. A typical URL is, for example, HTTP://LIB.STAT.CMU.EDU/. The first part shows the type of connection (http -- hyper text, telnet, gopher, ftp, etc.). The second part specifies the site (the Internet address) of the server, and the third part shows the path or file name. The files are stored in HTML (Hypertext Markup Language) format.

For accessing WWW, the most popular pieces of access software are MOSAIC and NETSCAPE. For textmode, LYNX is a commonly used WWW terminal software.



next up previous
Next: 4.3 WWW and ftp Up: 4 Archives and access Previous: 4.1 ftp



Andreas Krause
Mon May 15 19:18:23 MET DST 1995