Path: utzoo!attcan!uunet!crdgw1!ge-dab!sunny!harrison
From: harrison@sunny.DAB.GE.COM (Gregory Harrison)
Newsgroups: comp.realtime
Subject: Re: Non-determinism not "bad", per se. (Was: What is "real-time" really?)
Message-ID: <3830@ge-dab.GE.COM>
Date: 15 Mar 90 20:07:30 GMT
References: <98692@linus.UUCP> <1990Feb24.195542.21454@newcastle.ac.uk> <53174@sgi.sgi.com> <1208@tobor.cs.utexas.edu>
Sender: news@ge-dab.GE.COM
Reply-To: harrison@sunny.UUCP (Gregory Harrison)
Organization: GE Simulation & Control Systems Dept., Daytona Beach, FL
Lines: 31

In article <1208@tobor.cs.utexas.edu> mok@cs.utexas.edu (Al Mok) writes:
>
>
>  There are two steps in applying the deterministic/predictable approach.
> etc.  

Thank you for devoting the time to communicate from your expertise, and thanks
to all for the same reason.  I am working on a real time system, 
and the information you all have provided is aiding me tremendously.

I have learned many things from you all.  I am currently using the time-frame
approach toward sheduling real time flow.  I know that a few of my operations
take longer than others but I want to maintain synchronization on a 200 msec
frame time.  Inside this frame is 10 runs of my nonlinear, three integrator
simulator, plus I/O.  It responds to external   
stimulii, and hopefully provides an accurate simulation.  

Frame overflow exception could be handled better, now that you mention it.    
Currently I let the overflowing frame bump into the next frame, and eat up  
its free time, but your posting leads me to investigate further in order to 
perform some kind of self-altering algorithm that prevents the frame overflow
exception from occuring again, or at least ensuring that real time execution
is not glitched.  The frame overflow exception may occur, but the system
should get back into sync with the REAL TIME at the earliest possible 
opportunity.

Thank you all for your info, and for adding legitimacy and discipline to
my efforts.

Greg Harrison
(My opinions are not intended to express those of my employer)