W3 vs WAIS and Gopher


What's the difference betwen W3 and WAIS? What's the difference between W3 and Gopher? Why invent yet another system? Which one should I use?

The data model

W3 is comparable to both WAIS and Gopher , in that it is a client-server information system running over the internet. There is a difference in the data models. The W3 model is that everything (document, menu, index etc) is represented to the user as a hypertext (hypermedia) object. There two navigation operations are available to the user: to follow a link or to send a query to a server. Only certain documents are flagged as having a search facility, and not all documents have links, but some documents have both. That's a pretty simple model, and results in a pretty simple user interface.

Two neat things fall out of this model. One is that it turns out that almost all other information systems can be represented in terms of W3 documents. A W3 user can interrogate WAIS indexes (example) and Gopher servers (example). This comes from the flexibility of the W3 model to describe other structures. A WAIS database is a searchable document. The hit-list returned by a WAIS server (or any other query engine) is a hypertext document with links to the documents found. Gopher menus (or any other hierarchical menu system, including a file system) are represented as lists of items linked to other objects. The W3 system has an open addressing scheme allowing links to be made to any objects on W3, WAIS, Gopher, FTP, NFS, or Network News servers.

This flexibility has allowed lots of different kinds of data to be put on-line by writing a simple script to generate a hypertext "view" of the database.

The hypertext model, then, is flexible. It is also powerful as a communications medium. To author a document in hypertext is to communicate better. It allows one to put in a link whenever the reader might need background information .

WAIS without links

You miss the links in WAIS in two ways. One is when you are looking for an index. You can't follow links from an overview page to "browse" through different indexes. You can only use a master index (the directory of sources) to find indexes. The other way is that when you have retrieved something, whether part of the FORTRAN manual or part of a mail discussion, you get it in isolation. You can't follow links from that document to related documents.

Gopher without text

A Gopher menu is a dry list of items. Each line has 80 characters in which to describe an option. In practice, to communicate with the reader, one needs the full power of text formatting in a number of styles. A plain list turns out to be relatively infrequently used when the author or the program generating the document has a choice. Note that the "Panda" project adds some plain text to Gopher menus, but this is only a small step toward the flexible blending of links and text which is hypertext.

Group work

The second big difference is that W3 is designed to include collaborative authoring (CSCW) so that groups can share information, rather than simply individuals disseminate it. We only have a first stab at this on the NeXT platform, as we were overtaken by the web's success in dissemination mode.

Deployment levels

The W3 software is not (May 92) as deeply deployed as WAIS and Gopher software. This is basically because it takes more time to write a hypertext client than a menu or query client. (Also, because the initial W3 instigators are paid to work for the world of High-Energy Physics primarily).

However, the W3 world is growing very fast. There is widespread recognition that hypertext is essential for the next generation. It is planned to merge the W3 and Gopher systems, and there is no reason (apart from server simplicity and, perhaps, response time) why both of these systems could not use the WAIS protocol when it settles down.

The Choice

Bear in mind: So install W3 clients, and W3 servers. If you want to install a Gopher or WAIS server, fine: the W3 clients will access it. If you install a WAIS server, then you could install the W3-WAIS gateway locally to save bandwidth.


Tim BL