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CFHT Director/Agent Model
Revision 2.6

by Sidik Isani

1997 August 25th
Last revised: 1998 May 22nd

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The basic design concept in Director/Agent is keeping things as simple as possible. Although it may not scale well enough for some very large and complicated projects, it should be able to handle things like basic CCD and filter control more easily than the current handler/server model. The handler and server components are replaced by single, persistent ``agent.'' Combining the two reduces the need to pass and interpret messages going in both directions, and allows the same program that has control of the hardware to take direct commands from the user, without a custom communications protocol layer in between. Some flexibility in being able to run things from any host has been lost, but it's not clear that we really need that ability when it comes to passing user-level commands and getting a response.

Our first example of an agent is ``uh8kcom'', a somewhat modified version of mcdcom, written by Mark Metzger at University of Hawaii. The modifications needed to get it to run under director were very minor things like changing the way the prompt looks and formatting of program output. (Modifications to clean up the code itself are a different issue. This is still in progress but has very little to do with interacting with director.)

The Director allows an agent to be incorporated into a Pegasus session, It even enhances some aspects of sessions that do have an agent. Best of all, Director is complete and ready to go! (But of course not without a ``wish list'' of future features.)

next up previous contents
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Sidik Isani