- - Idle time

From: Douglas G. Danforth <"Douglas>
Date: Fri, 29 Apr 2005 11:47:51 -0400

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Zinn, Helmut wrote:
> Dear Doug, dear Wojtek,
>
> be careful. You lead so up the garden path. MS Windows (95, 98, ME, NT, 2000
> and XP) are NOT a Real-Time Operating System !!!
>
> The same program with the same data may run usually in 5 seconds, but
> occasionally it needs 15 seconds or even more.
>
> Do you know what happens if the interrupt occurs before the last one is
> finish and this repeats a lot of time? Certainly you send a bug report to OM
> and you forget to tell about that you have change idle Period to 1 ms.
>
> Do you know how much spare time is available at the 1 ms rate? Are there
> enough time left for the application programs? What happens if the garbage
> collection needs more time?
>
> Of course you can develop and shows the principle of Real-Time-Application
> with Blackbox, but for the final work you need a Real-Time-Operating System.
> OM sells such a Real-Time Operating System. It is calling PORTAS.
>

Helmut,
I agree with you that this is walking up the garden path. The test says
to me that the overhead for a BlackBox loop takes at least 10ms and your
concerns are valid. (For the fun of it I changed the setting of
idlePeriod to 10ms and retested and again got about 10ms response so
that is operating near the limit. I spend a little time opening and
closing windows, running some programs, doing some searching with the
modified system and all seemed to work ok but that proves nothing).

I used Google to search for PORTAS and Oberon Microsystems and found
nothing. I do vaguely remember mention of PORTAS some years ago. Do
you have a pointer to a description of the system?

RTOS:
The problem with working with a system specifically designed for
real-time operation is that it (may) lack general facilities such as
provided by BlackBox. Idealy one (physicists) want to be able to drop
into a mode where real-time is available (microseconds and below) and
then step back to a general system.

That's why I was so excited to find that threads allowed me to operate
in 10s of nanoseconds. That discovery completely changed my view of the
machine at my finger tips. It suddenly became a true scientific
instrument with vast possibilities. Alas, thread safety hobbles that dream.

-Doug

--- BlackBox
--- send subject HELP or UNSUBSCRIBE to blackbox{([at]})nowhere.xy



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Received on Fri Apr 29 2005 - 17:47:51 UTC

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