Introduction and overview of hypertext systems and applications

Overview

There was an interesting but not too exciting overview of existing systems, all mutually incompatible and limited to homogeneous environments. The speaker works for IRIS , the commercial branch of Brown University. They developed a hypertext system called Intermedia , so a demonstration of this was obviously included.

The following list of highlights is NOT to be taken as a list of possible candidates for a CERN hypertext system (let alone as a list of recommendations), it is of interest only for the ideas that have been implemented in what I (RC) would emphasise are still embrionic systems.

NLS/Augment, (1969!)

structured documents, kept as outline, which allows zoom-in and zoom-out. Link anchors are full pathname and therefore can be across machines.

Xanadu

Ted Nelson's dream since early `60s: all the world literature in one publicly accessible global online system (analogy: you can today get a telephone link from anywhere to anywhere, so why not from any text to any other?). Every reference to a text will lead to royalties being paid automatically to the author. Autodesk, (the makers of AutoCAD) will produce a product "real soon now". Includes the use of full versioning (claimed to be horrifyingly complex), "hot links" (called transclusions) and zippered texts (eg. parallel texts like for translations or annotations.)

NoteCards (Xerox PARC)

Written in Interlisp D, single user, uses the card metaphor. There are two camps: the card sharks, who propone the idea that information comes in card-size chunks, and the holy scrollers, who propone that a hypertext node can essentially be any size and therefore has to be scrollable on the screen.

NoteCard links can be labelled with keywords for filtering. The most useful part of the system is its graphical browser, wherein the user can pick documents or edit links between them. There is one composition methaphor, the Filebox.

KMS (marketed by Knowledge systems)

A card system (claimed to have the Hypercard model but in 1972), wherein graphics and text can be mixed. The com- mercial version allows two card windows side by side (for copy-and-paste operations). It was described as "MacDraw with links". Its main feature is that sub-second response time is one of the design criteria. Scripts were first used in KMS: the traversal of a link can result in the execution of a piece of code of arbitrary complexity and effect (eg. Unix shell scripts). There is no graphical browser. KMS is multi-user but does not warn anyone of simultaneous access, so during updating, if two people edit the same node, one loses...

Hyperties (university of Maryland)

Designed for browsing (idea that many users will look at information, only a few will author it), so it is asymmetric and the authoring system is not nearly as easy to use as the browser. Sinlge user, runs on PCs with a research version for the Sun. Anchors are created with markup in the precompiled text.

Intermedia

A research tool developed at Brown university (van Dam (yes, Andy,) et al). The demo was impressive. There is a data base system parallel to the texts, that holds the links. A web is a context of links, several webs can be created over the same set of documents. Several links can emanate from the same anchor. Web views can be presented, and they also give the history of viewing for each user. It runs under Apple's old Unix version for the Macintosh (and will not run on the current version). It seems to be dead, since there is no funding to continue the research.

Guide

A product from Owl International, a UK company. Guide is based on Peter Brown's work (U. of Kent, 1984). Runs on MS-Windows and Macintosh with a development version for Unix. Documents may contain text and graphics, struc- ture is given in application-specific files called "guidelines". Access to video and documents from other applications possible. There is no web visualisation.

Hypercard

The system for the Macintosh (Apple, 1987). Many claimed this not to be a hypertext system, but then the majority of real applications presented used it. This is the product that made hypertext take off. It is the BASIC of the 1990s. It follows the card model (but has scrolling fields...) Incorporates graphics and text. Other media are accessible through extensions. Powerful scripting language. It is the only one with which I personally have a lot of experience. The prob- lem with Hypercard is that any fancy application requires writing scripts, but its advantage is that the scripting language allows you to do most of the things that are absent from other systems.

Toolbook

· Hypercard like but has an object type drawing package rather than canvas type, and an object oriented scripting lan- guage. From what little was said about it, it seems to be better than Hypercard.

Analyst

· Runs over ParcPlace SmallTalk, available for Sun, Mac, Dos. The document model is of an information centre where different types of documents are assembled from forms, databases, spreadsheets, maps, graphics and folders (which are like directories). Each document type has its own editor. Queries may result in virtual folders, somewhat like SQL views. Some support for artificial intelligence.