The Developement Tool Xdev

Table of Contents

Francisco Esquembre
Murcia

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1. Global Description

Xdev is an authoring system that simplifies the creation of simulation modules. It runs on HP workstations under X windows and Motif.

Xdev has an interface builder and an interpreter based on a subset of C with some extensions. These two elements support the development of a graphical interface as well as the code for the model of the simulation and the response of it to user interactions.

The program can run in interpreted mode for the development and testing phase, but also faster and independent executables can be generated. Using dynamic linking, Xdev also provides hooks for the more experienced programmers to include their own functions.

The whole system is extensible for new widgets and libraries, and is site and user customizable.

The system is provided with some new widgets devoted to the display of scientific data in 2 and 3 dimensions, as well as new input widgets.

2. Scope of Programming Work

Xdev hides most of the programming issues inherent to Unix, X-windows and Motif and lets the user concentrate on the model for the simulation. It is hence very well suited for beginners to this platform.

It also speeds up the development of the interface and the assignment of callbacks (or responses to user interactions) and the setting of a periodic process, which makes it useful also for expert programmers.

3. Target group

Xdev is targeted to teachers of all kinds or science students, which are able to specify their algorithms, equations, models,. in a high level computer language, but are not expert programmers or Unix users. It will allow them to access powerful machines and add nice graphical interfaces to their programs.

As a prerequisite, a minimum knowledge of the C programming language is needed. Knowing the philosophy of Motif (what is a widget, a callback, a resource,...) is also needed. Having an idea of some of the widgets available helps a lot.

4. Available help

Xdev comes with a manual in printed form and has some built-in browsers that help navigating through Motif graphical components or widgets, providing a list and a short description of their resources (customizable internal values) and callbacks (possible responses to user interaction).

Most frequently used widgets are presented in a graphical way in a pick-and-use panel, thus facilitating access.

A tutorial to start creating simple programs exists already. A cook-book for individual components and of common interactive situations is being prepared.

A set of complete examples, some of them of considerable complexity and of scientific interest is included in the distribution package.

5. Status

Xdev is now a stable product. It will be subjected to improvements suggested by users. Some minor bugs have been reported and will be taken care of. Speed is not a critical issue because executables can be generated at any moment during the development phase, and these show the speed of the final product.

In general, it can be said that the system produces executables that are as fast as those generated by an expert programmer. Right now, the system runs only on Hewlett Packard series 700 workstations with X11 R4 and Motif 1.1. It is planned to move soon to X11 R5 and Motif 1.2.

Because the system produces executables, the C development software package (which is not included in the standard HP-UX distribution) has to be installed on the system.

6. Evaluation

The program has been used extensively by a small group of teachers and students (both under-graduate and post-graduate) who had basic knowledge in programming. As an average, they were able to produce their first complete program related to their different scientific domains in about 3 to 4 weeks (working 1 to 2 hours daily). The teachers who continued developing with Xdev are now able to produce their software much faster. Because they had to concentrate more on their subject than on programming issues, they were very motivated to use Xdev, and very pleased with their results.