HTML, being a standard for formatting information, rather than a package, directly addresses the issue of platform independence its main purpose after all is to overcome the problems that arise when computers of different kinds are connected to one another for information transfer.
Acrobat also aims to overcome the problems of platform dependence. It places particular emphasis on preserving the appearance of the electronic page, even to the extent of being able to create reasonable substitutes for fonts missing from the end-user's machine. Files for Acrobat (PDF files Portable Document Format) can be viewed in a self-contained viewer, or can be viewed using the Acrobat plug-in for browsers such as Netscape.
Director can produce stand-alone applications for Windows, Macintosh and other platforms, though the files themselves are specific to the platforms for which they are made duplicate files are needed where two platforms are to be supported.
Director's Shockwave files, offering much of the functionality of full Director files, being designed specifically for the Web, are not confined to a single platform. The file is played for the user by means of a plug-in for a browser such as Netscape.
Director is a rather expensive authoring package, even when educational discounts are taken into account. Stand-alone Director files (ie which do not need the authoring package in order to be used) and Shockwave files can be distributed free of charge where publication is not for profit (though the use of the authoring package must be acknowledged). Where files for more than one platform are required, a copy of the authoring package must be purchased for each platform, usually Macintosh and Windows. Files made to deliver over the Web are processed in an ancillary package called Afterburner.
Acrobat has two principal components: one, moderately expensive, for authoring (Acrobat Exchange) and one for browsing (Acrobat Reader). The Reader can be distributed free with Acrobat files. The educational discount is currently substantial.
It must be admitted that the future financial position concerning the authoring and browsing tools for HTML documents is unclear. For example, when the most popular browser Netscape changed from being shareware to a commercial product, it remained free to education users. We have to assume that Netscape or a similar comprehensive browser will be on every computer in HEIs since it provides such an important component of access to the Internet, which all students and staff will want for many reasons (particularly research). Shareware and freeware browsers are also available. If comprehensive browsers like Netscape ceased to be free, the effect on the HE community would be very serious.
A related issue is that of the openness of the system. The three technologies evaluated cover the range from complete openness (HTML) to a closed proprietary format (Director). The PDF (Portable Document Format) of Adobe is a published format and so in that sense is open but, unlike HTML, PDF does not have the advantage of a number of tools from a wide range suppliers to both produce and read its documents.
Simple HTML documents can be created using a basic text editor: all the tagging which dictates their appearance and basic functions consists of text. However, authors are sometimes not in a position to quickly see the results of their choices, and this indirectness in which a component is specified, tested, then revised may be a problem for some authors who need a more direct and intuitive relationship with their material. Using a more visual package to generate the HTML marked up pages may be preferable and in future is likely to become the standard way of working. Examples include paper-publishing tools such as PageMaker or Quark XPress which now have HTML as an optional output, and packages specifically for creating Web pages such as Adobe's PageMill. A SIMA project to evaluate such tools is listed in the Web Resources (p110).
The browsing software for HTML documents is simple to use, partly because of its lack of a rich collection of functions (see below), and partly because the functions which it does support are implemented in a standardised manner likely to be familiar to anyone who has used window+pointer based computing systems. By contrast, documents made with Director are only standard in their appearance and behaviour if the author is both willing and competent to make them so.
In one sense Acrobat requires no new skills at all, since at its simplest it can be used to take pages which have been designed as sheets of paper, simply presenting these as virtual paper' on screen (the method is to print' documents to a disk-file using a virtual printer' driver, instead of to an actual printer).
Graphics Multimedia Virtual Environments Visualisation Contents