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Proceedings Paper

Progress in cancellable multi-threaded control software
Author(s): K. Shortridge; T. J. Farrell
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Paper Abstract

The AAO's DRAMA data acquisition environment provides a very successful flexible model for instrument control tasks based on the concept of named 'actions'. A task can execute a number of these actions simultaneously, and - something we have found to be of paramount importance in control systems - they can be cancelled cleanly if necessary. However, this flexibility has been achieved by use of what is essentially a collaborative multi-threading system, each action running in short 'stages' in a single-threaded task. The original DRAMA design pre-dated the general availability of multi-threading systems, but until now we have been reluctant to move to a multi-threading model because of the difficulties associated with attempting to cleanly cancel a thread stuck in a blocking operation. We now believe we have an acceptable solution to this problem, and are modifying the internals of DRAMA to produce an approach - compatible with the existing system - that will allow individual actions to execute in separate threads. It will be able to carry out dialogues with hardware in a much simpler manner than has been allowed so far, and this should simplify the coding of DRAMA tasks enormously.

Paper Details

Date Published: 19 July 2010
PDF: 8 pages
Proc. SPIE 7740, Software and Cyberinfrastructure for Astronomy, 774029 (19 July 2010); doi: 10.1117/12.856217
Show Author Affiliations
K. Shortridge, Anglo-Australian Observatory (Australia)
T. J. Farrell, Anglo-Australian Observatory (Australia)

Published in SPIE Proceedings Vol. 7740:
Software and Cyberinfrastructure for Astronomy
Nicole M. Radziwill; Alan Bridger, Editor(s)

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