WIMOVAC was written in Microsoft Visual Basic (v. 2.0/3.0) an event driven, pseudo-object orientated and visual programming language which provided the user interface design components necessary for our specification. Although Visual Basic has similarities to earlier versions of BASIC, such as Microsoft Quickbasic 4.5 or the Microsoft BASIC Professional Development Kit 7.0 in its use of variables, constants and intrinsic functions, Visual Basic adds a higher degree of modularity and code structure as well as introducing a number software tools, called custom controls, for the rapid development of Windows 3.1 programs. Visual Basic gives most of the flexibility and discipline of other structured languages, such as PASCAL, C and C++, but allows the rapid development and prototyping of visual control elements. It is these visual control elements which are essential to providing non-computer expert access to the models in WIMOVAC.

In its native form Visual Basic is an interpreted language which makes program development and testing a faster process than with traditional compiled languages. For distribution purposes to end users the interpreted source code (pseudo-p code) can be simply compiled however, to form a stand alone executable program (WIMOVAC.EXE) compatible with the Windows environment and which may be run from the Windows desktop or program manager in the usual manner. A number of commercial custom controls are available for Visual Basic which extend standard functionality by providing simplified access to complex facilities such as graphing, spreadsheet style data handling and customised user interface components. WIMOVAC makes use of a number of these controls to extend automatic graphing, printing, clipboard and data handling facilities to the user. In addition WIMOVAC makes use of Windows object linking and embedding technology (OLE) for the transfer of simulation results directly from WIMOVAC to other Windows based applications for sophisticated analysis, manipulation and printing using such dedicated packages.

WIMOVAC uses the Microsoft Help Compiler (version 3.1.1) to incorporate the on-line context sensitive hyper-help system containing segmented hyper graphics, equations, bitmaped images and scaleable Windows metafile images (figure 1).

The WIMOVAC help file has been constructed using a word processor WFW (Microsoft Word for Windows v6.01). WFW is used to create rich text files (RTF) containing the textual information and inserted graphics which the help compiler then builds into a help file format compatible with the help file manager and display system built into Windows 3.1 and related operating systems. The advantage of using the word processor route is that expert scientists may contribute without the need for any programming skills. A further advantage offered by preparing an on-line help system in this manner is that the word processed help file may be used, to form the basis of a printed manual or hardcopy documentation of the modelling system.