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From: Jacob Sparre Andersen <jacob@jacob-sparre.dk>
Newsgroups: comp.lang.ada
Subject: Re: How to: communication between multiple tasks using protected
 objects - with no polling?
Date: Wed, 21 Jan 2015 19:56:17 +0100
Organization: Jacob Sparre Andersen Research & Innovation
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Date: 2015-01-21T19:56:17+01:00
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Esa Riihonen wrote:

> So - in my mind I have a small number of students each with a separete
> blackboard. And instead of my teacher walking around checking whether
> the answer of any of the sudents is ready - I wan't to let the teacher
> doze in his/her chair and only be woken up when any of the students
> have their answer ready. And after the student briefly nudges the
> teacher he/she must be free to immediately continue with his/her other
> exams.
>
> I guess I just don't know how this 'blackboard' model should be
> implemented?

To me it sounds like a single protected object for storing the state of
all the workers (students) makes most sense.  The workers can push in
their most recent state through a (common) protected procedure.  The
master (teacher) blocks on a protected entry until at least one worker
has updated its state.

Greetings,

Jacob
-- 
"Facts do not cease to exist because they are ignored." -- Aldous Huxley