For a number of years, the term 'convergence' has been used to describe the coming together of computer and video technology. But there is another convergence taking place in the computer industry: the convergence of text and applications.

Early computer interfaces were built around the teletype model - a modified typewriter where each message appeared on the bottom line and 'pushed' the rest of the text up. The next step was the 'glass teletype', or early VDU (visual display unit). These made possible the development of typical 'green-screen' applications, where whole screen-loads of information were transmitted to a mainframe. In order to cut down on processing, the terminal provided the tools to allow the user to type information into all of the 'fields' on the screen before transmitting the whole thing in one package to the computer.

The format of a terminal was such that the presentation of large amounts of text was not feasible. Reading any sort of bulk text on a terminal is like reading a newspaper through your letterbox. A separation between applications and text was forced by the 'green screen' technology. Applications were written by applications programmers, and documentation was written by technical writers.

With the advent of the PC, graphical user interfaces became the norm. Here, you could actually view text on-screen in reasonable comfort. Today, typical applications have on-line help, but it's often little better than an electronic version of a paper manual. Many technical writers still worry about how to 'single source' paper and online documentation from the same text, reflecting the fact that much online help is just electronic paper.

There is an artificial separation between the application - made up of static 'field labels' and fill-in 'fields', and the description of what to do with the application: the user documentation. Why not combine the two, converge them if you like, into one medium?

An early first step along this path was the 'Wizard': a series of screens with their own built-in descriptions. Another step was the model developed by Lotus for their Notes application - a major innovation of which was discarding the limitations of a fixed screen and allowing the 'form' (consisting of both text and data) to be scrollable, allowing large amounts of text to be mixed with the data. And of course the web: scrollable by necessity, as the early HTML model didn't allow the screen designer any control over the length of screen presented at the browser.

What might a 'converged' application look like? It would make no distinction between static information about the job in hand (business rules and procedures) and about the software (descriptions of how to use the interface). It would integrate the collection and display of data with its documentation. It would allow the 'static' instructions to be driven by the data, changing as the data changed.

To develop such an application would need a development environment which allowed the authoring, layout and on-the-fly modification of text as easily as other data. It would treat user communication as part of the application, rather than a separate function tacked on to explain the interface to the user.

But there are any number of technologies around that make this sort of thing possible: you could currently build a 'converged' application in anything from PDF to Word to DHTML. The technology isn't what's holding us back, and hasn't been since Windows 3.0.

What's holding us back is the too-clear distinction between technical writing and applications development. Both use text to allow people to interact with computers, and there is no technical reason why they should be treated differently; but they are.

Time for convergence?