Subject:
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RE: Tasks in RCX
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Newsgroups:
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lugnet.robotics
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Date:
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Tue, 21 Dec 1999 23:56:51 GMT
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Original-From:
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Tilman Sporkert <tilman@(SayNoToSpam)activesw.com>
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Viewed:
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440 times
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> In lugnet.robotics, Ram Meenakshisundaram writes:
> > Hi,
> >
> > I read somewhere that the RCX is limited to only 10 concurrent tasks.
> > Is this limitation in the firmware? If so, can I use a replacement
> > firmware like legOS to overcome this. I basically want to have an
> > unlimited number of tasks so that I can port OCCAM-2 to the RCX. Thanks
>
> <chuckle> 10 seems like a small number (yes its limited by the firmware)
> until you try to use them all. In my experience only email and webserver type
> applications kick off more than 4 or 5 threads at once.
That highly depends on the programming environment, and the skills and
preferences of the programmer. Thread creation and management is very easy in
Java, and therefore, Java programmers tend to use threads more liberally for
example. Dozens of threads are common in applications I'm working with.
The RCX environment leads you towards liberal use of concurrent tasks, too. You
don't want to stop monitoring your sensors while performing some motor
operations for example. The big red "Emergency shut down" button has to work at
any time. Other real-time operation systems use interrupt handlers to accomplish
the same goals.
The RCX has a limited number of inputs (3 sensors, IR, timer, counter) and
outputs (3 motors, speaker). That limits the number of useful tasks that you can
have. Not many people using the Lego Mindstorms programming environment will be
seriously inconvenienced by a limit of 10 concurrent tasks.
Tilman
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Message has 1 Reply:
 | | Re: Tasks in RCX
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| Not sure about the newer VM's, but the early Java systems got bogged down pretty quickly when you started to fire up lots of concurrent threads, particularly if you were doing 'real-time' type tasks such as animation or network access. This sort of (...) (25 years ago, 22-Dec-99, to lugnet.robotics)
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Message is in Reply To:
| | Re: Tasks in RCX
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| (...) <chuckle> 10 seems like a small number (yes its limited by the firmware) until you try to use them all. In my experience only email and webserver type applications kick off more than 4 or 5 threads at once. DLC (25 years ago, 21-Dec-99, to lugnet.robotics, lugnet.robotics.rcx)
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