What is wais?

Purdue Engineering Computer Network

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Wide Area Information Service (WAIS, pronounced "wayz") is another of the Internet's services. It's great for searching through indexed material and finding articles based on their contents. That is, WAIS lets you search through Internet archives looking for articles containing groups of words.

The format of the information presented doesn't matter much. It doesn't really look at the data in the process of a search, it looks at an index. If you or someone else takes the trouble to build an index, WAIS can select information and present it to you regardless of its format. It's most common to see indexes for various kinds of text (articles and so on), but you can build an index for anything.

Like Gopher, WAIS allows you to find and access resources on the network without regard for where they really reside. In Gopher, you find resource by looking through a sequence of menus until you find something appropriate. WAIS does the same thing, but it does the searching for you. A WAIS command is essentially, "find me items about this in that library". There are more than 500 free WAIS libraries on the network now.

How WAIS Works

To make a document available through a WAIS server, someone must create an index for that server to use in the search. For textual information, every word in the document is usually indexed. When you request a search from a WAIS client, it contacts the servers that handle the libraries you suggested. It asks each server, in turn, to search its index for a set of words. The server then sends you a list of documents that may be appropriate, and a "score" telling how appropriate it thinks each one is. WAIS looks in the index and counts how many times each document contains the word you are searching for. WAIS gives you the titles of the documents that received the highest scores, you can then pick which documents to view, and WAIS will display them for you. There are no special words in WAIS; every word counts in the ranking.

Getting Access

Accessing WAIS is a lot like accessing Gopher. In order to use it, you need a computer running a WAIS client program. You can install the client program on your own workstation, or you can access a computer that already has the client installed and run it there.

There are WAIS clients for most standard operating systems and computers. We will be looking at three WAIS clients for UNIX systems:

• UNIX line-oriented interfaced called swais.
• Graphical client which runs under the X Window System called xwais.

The line-oriented client is available at a number of public-access sites around the Internet. You can telnet to a particular computer and login with a special ID, like "wais", and do some simple searches. However swais is more difficult to learn because it requires several commands and keystrokes just to set up a search. Graphical clients, like xwais or the Mosaic interface WAISGATE, are easier to use.

On many of these clients you will see a directory of servers. This is a list of all known servers for the WAIS system, offered as a WAIS database. The directory of servers is usually the first database you'll search when you start a WAIS search; it's where you'll find the databases that are relevant to the topic you're researching.