[Tinyos-host-mote-wg] [Tinyos-2.0wg] Resource Interface

[Kevin Klues]

I have a question about the requested() event in the Resource interface....
Should this event be signalled when calls to immediateRequest() are made 
as well, or only when calls to request() are made?

The question is really whether the requested() event actually signals 
that someone has requested the resource or if it notifies the current 
Resource owner that requests are waiting in the queue.  If it is the 
former, then the answer is yes... signal the event.  If the latter, then 
the answer is no... don't signal the event.

Either way I see a problem though.
Imagine two users of a resource.  The first uses the request() command 
and always try to hold on to the resource, unless someone else requests 
it.  the second  uses the immediateRequest() command and does not 
perform its function if this call fails. 
The requested() event is not signalled:
  -- The first user will have exclusive access to the Resource
  -- The second user will never get a chance to use the resource. 
The requested() event is signalled:
  -- The first user will release the resource
  -- The second user will not immediately request the Resource again 
because he has no way of knowing it was released and his request is not 
stored on the Resource queue
  -- the first user reaquires the resource and ends up having exclusive 
access again.

I'm not saying this is a really realistic scenario for the use of the 
Resource interface, but I thought it would be something to think about.

Kevin



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