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Re: How to avoid a task not executed in a real-time OS?

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> I was asked the question in the title some time ago. I had some real-time
> embedded system experience but with RTOS. A watch-dog can avoid a task not
> called in a real-time system. But in a RTOS, what is the right answer for it?
> I knew task priority, a timer triggered event all can influence a task execution.

It's a peculiar choice of words in asking these questions.  I'm not sure 
exactly what you mean by "avoid".

In a typically designed single core system, at least one RTOS task is 
always present (blocked or waiting) but not always actively doing work 
(running).  There is always more than one task, otherwise there is no 
justification for using an RTOS.  The programmer can (usually) start 
(create) and stop (kill) tasks.  Task creation usually happens at init 
time but there's no rule the forces that design.  If you want to avoid 
the task running state, kill the task or inhibit the input to unblock 
it.  You decide as the programmer.

Task priority is a means to direct a lower priority task to yield CPU 
usage while a higher priority task is running.  When the high priority 
task is done running (that is, it blocks), the lower priority task 
automatically runs if it's runnable (not blocking).  Task priority can 
delay a task running in response to what unblocked it but not inhibit it.

That's a simplified answer.  Some RTOS's are quite sophisticated and the 
answers get complicated when you use their advanced features.

JJS

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How to avoid a task not executed in a real-time OS? Robert Willy <rxjwg98@gmail.com> - 2019-01-21 04:40 -0800
  Re: How to avoid a task not executed in a real-time OS? John Speth <johnspeth@yahoo.com> - 2019-01-21 06:27 -0800
  Re: How to avoid a task not executed in a real-time OS? Stef <stef33d@yahooI-N-V-A-L-I-D.com.invalid> - 2019-01-21 17:55 +0100
  Re: How to avoid a task not executed in a real-time OS? Richard Damon <Richard@Damon-Family.org> - 2019-01-21 13:05 -0500
    Re: How to avoid a task not executed in a real-time OS? upsidedown@downunder.com - 2019-01-22 08:05 +0200
  Re: How to avoid a task not executed in a real-time OS? Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2019-01-21 22:44 +0100
  Re: How to avoid a task not executed in a real-time OS? David Brown <david.brown@hesbynett.no> - 2019-01-22 09:19 +0100
    Re: How to avoid a task not executed in a real-time OS? Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2019-01-22 22:10 +0100
      Re: How to avoid a task not executed in a real-time OS? Dave Nadler <drn@nadler.com> - 2019-01-22 13:28 -0800
      Re: How to avoid a task not executed in a real-time OS? David Brown <david.brown@hesbynett.no> - 2019-01-23 08:57 +0100
        Re: How to avoid a task not executed in a real-time OS? Paul Rubin <no.email@nospam.invalid> - 2019-01-23 13:13 -0800
          Re: How to avoid a task not executed in a real-time OS? David Brown <david.brown@hesbynett.no> - 2019-01-24 08:31 +0100
  Re: How to avoid a task not executed in a real-time OS? George Neuner <gneuner2@comcast.net> - 2019-01-22 05:01 -0500
  Re: How to avoid a task not executed in a real-time OS? StateMachineCOM <statemachineguru@gmail.com> - 2019-01-28 07:17 -0800
    Re: How to avoid a task not executed in a real-time OS? "A.P.Richelieu" <aprichelieu@gmail.com> - 2019-01-28 20:15 +0100
      Re: How to avoid a task not executed in a real-time OS? StateMachineCOM <statemachineguru@gmail.com> - 2019-01-28 12:31 -0800
        Re: How to avoid a task not executed in a real-time OS? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2019-01-28 16:22 -0500
          Re: How to avoid a task not executed in a real-time OS? Clifford Heath <no.spam@please.net> - 2019-01-29 10:17 +1100
            Re: How to avoid a task not executed in a real-time OS? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2019-01-29 10:08 -0500
              Re: How to avoid a task not executed in a real-time OS? StateMachineCOM <statemachineguru@gmail.com> - 2019-01-29 09:30 -0800
                Re: How to avoid a task not executed in a real-time OS? Tom Gardner <spamjunk@blueyonder.co.uk> - 2019-01-29 18:22 +0000
                Re: How to avoid a task not executed in a real-time OS? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2019-01-29 13:50 -0500
                Re: How to avoid a task not executed in a real-time OS? Clifford Heath <no.spam@please.net> - 2019-01-30 09:45 +1100
                Re: How to avoid a task not executed in a real-time OS? Tom Gardner <spamjunk@blueyonder.co.uk> - 2019-01-30 00:56 +0000
          Re: How to avoid a task not executed in a real-time OS? Reinhardt Behm <rbehm@hushmail.com> - 2019-01-30 13:32 +0800
        Re: How to avoid a task not executed in a real-time OS? "A.P.Richelieu" <aprichelieu@gmail.com> - 2019-01-30 19:07 +0100
  Re: How to avoid a task not executed in a real-time OS? StateMachineCOM <statemachineguru@gmail.com> - 2019-01-30 12:31 -0800
    Re: How to avoid a task not executed in a real-time OS? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2019-01-30 16:23 -0500
    Re: How to avoid a task not executed in a real-time OS? "A.P.Richelieu" <aprichelieu@gmail.com> - 2019-01-31 06:05 +0100
    Re: How to avoid a task not executed in a real-time OS? kegs@provalid.com (Kent Dickey) - 2019-02-02 10:44 -0600
      Re: How to avoid a task not executed in a real-time OS? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2019-02-02 12:19 -0500

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