Date: Thu, 5 Feb 1998 01:26:18 -0500 From: "Jean-Marc Henriette" <jeanmarc@starfleet.umd.edu> To: freebsd-questions@FreeBSD.ORG Subject: Real time on freebsd Message-ID: <9802050126.ZM3699@starfleet.umd.edu>
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Thanks for all the responses I got! Saldy I didn't do a good enough
job of specifying what I wanted to do, hence I'll restate my question by
including a bit more info.
I work at a lab here at the university of maryland which is involved
in the design of a space robot. In order for this robot to function properly,
we have to be able to run a function at a constant rate. Since this rate
plays back into the algorithm itself, it is important that this loop stay at
a constant 200 hz. The accuracy of this loop must be within a percent or so.
The original question was wether FreeBSD had some sort of way to make sure that
this loop rate stays constant over time. Most Real Time implementation that I
have seen actually use the clock interupt as a method of triggering these
functions, thus making the system fairly deterministic. How hard would this be
to implement on FreeBSD?? I've thought of using the alarm signals, but I am
unsure of the latency involved with signals, as well as the accuracy of the
clock it uses.
thanks again!
Jean-Marc Henriette
University Of Maryland Space Systems Lab.
http://www.ssl.umd.edu
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