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Paper: Use of Inheritance Techniques in Real-Time Systems under DRAMA
Volume: 77, Astronomical Data Analysis Software and Systems IV
Page: 391
Authors: Farrell, T. J.; Shortridge, K.
Abstract: In real-time instrument control systems such as the AAO's DRAMA system, where relatively complex individual tasks control their own parts of a system (spectrograph, camera, telescope, etc), there are often significant similarities between tasks. At AAO, all DRAMA tasks have a number of standard ``actions'' such as ``INITIALISE'', ``RESET'' and ``EXIT'', and all camera control tasks provide actions such as ``WINDOW'', ``EXPOSE'' etc. We have developed a mechanism which allows tasks to ``inherit'' code from a generic instrument task, a generic camera task, etc. This makes the initial coding easier and also enforces the standard behavior we require of our tasks. Such techniques for inheriting the behavior of software objects have become popular over recent years, with most attention focusing on C++ and similar languages. DRAMA is written in C, but combines ideas from the X Windows Xt toolkit with its use of named actions in tasks to provide a successful, effective, inheritance mechanism.
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