Hypertext is a way to link and access information of various kinds as a web of nodes in which the user can browse at will. Potentially, Hypertext provides a single user-interface to many large classes of stored information such as reports, notes, data-bases, computer documentation and on-line systems help. We propose the implementation of a simple scheme to incorporate several different severs of machine-stored information already available at CERN, including an analysis of the requirements of information access needs by experiments.

Hypertext is a way to link and access information of various kinds as a web of nodes in which the user can browse at will. Potentially, Hypertext provides a single user-interface to many large classes of stored information such as reports, notes, data-bases, computer documentation and on-line systems help. We propose the implementation of a simple scheme to incorporate several different severs of machine-stored information already available at CERN, including an analysis of the requirements of information access needs by experiments.



The current incompatibilities of the platforms and tools make it impossible to access existing information through a common interface, leading to waste of time, frustration and obsolete answers to simple data lookup. There is a potential large benefit from the integration of a variety of systems in a way which allows a user to follow links pointing from one piece of information to another one. This forming of a web of information nodes rather than a hierarchical tree or an ordered list is the basic concept behind Hypertext.

At CERN, a variety of data is already available: reports, experiment data, personnel data, electronic mail address lists, computer documentation, experiment documentation, and many other sets of data are spinning around on computer discs continously. It is however impossible to "jump" from one set to another in an automatic way: once you found about that the name of Joe Bloggs is listed in an incomplete description of some online software, it is not straightforward to find his current electronic mail address. Usually, you will have to use a different lookup-method on a different computer with a different user interface. Once you have located information, it is hard to keep a link to it or to make a private note about it that you will later be able to find quickly.

Hypertext concepts

A program which provides access to the hypertext world we call a browser. When starting a hypertext browser on your workstation, you will first be presented with a hypertext page which is personal to you: your personal notes, if you like. A hypertext page has pieces of text which refer to other texts. Such references are highlighted and can be selected with a mouse (on dumb terminals, they would appear in a numbered list and selection would be done by entering a number). When you select a reference, the browser presents you with the text which is referenced: You have made the browser follow a hypertext link.

The texts are linked together in a way that one can go from one concept to another to find the information one wants. The network of links is called a web. The web needs not be hierarchical, and therefore it is not necessary to "climb up a tree" all the way again before you can go down to a different but related subject. The web is also not complete, since it is hard to imagine that all the possible links would be put in by authors. Yet a small number of links is usually sufficient for getting from anywhere to anywhere else in a small number of hops.

The texts are known as nodes. The process of proceding from node to node is called navigation. Nodes do not need to be on the same machine: links may point across machine boundaries. Having a world wide web implies some solutions must be found for problems such as different access protocols and different node content formats. These issues are addressed by our proposal.

Nodes can in principle also contain non-text information such as diagrams, pictures, sound, animation etc. The term hypermedia is simply the expansion of the hypertext idea to these other media. Where facilities already exist, we aim to allow graphic interchange, but in this project, we concentrate on the universal readership for text, rather than on graphics.

Operation

A link is specified as an ASCII string from which the browser can deduce a suitable method of contacting an appropriate server. When a link is followed, the browser addresses the request for the node to the server. The server therefore has nothing to know about other servers or other webs and can be kept simple.

Once the server has located the requested node, it will know from the node contents what the node's format is (e.g. pure ASCII, marked-up, word processor storage and which word processor etc.). The server then begins a negotiation with the browser, in which they decide between them what format is acceptable for display on the user's screen. This negotiation will be based only on existing conversion programs and formats: it is not in the scope of W3 to write new converters. The last resort in the negotiation is the binary transfer of the node contents to a file in the user's file space. Negotiating the format for presentation is particular to W3.

Future paths

Though the results seem ambitious, the individual steps necessary are well within our abilities with available technology. Future developments which would further enhance the project could include:
- Daemon programs which run overnight and build indexes of available information.
- A server automatically providing a hypertext view of a (for example Oracle) database, from a description of the database and a description of the view required.
- Work on efficient networking over wide areas, negotiation with other sites to provide compatible on-line information.
- A serious study of the use and abuse of the system, the sociology of its use at CERN.

© T. Berners-Lee / R. Cailliau, 1990