[cadynce] Meditations on Learning and a Big Back End

[Cross, Joseph]

Raj -

Thank you for your always insightful comments. A couple of questions:

> We can (and should) take care of 
> requirements such as schedulability in the bin-packing phase. 

That means while we're sailing on the Cubicle Sea, right? If so, do you
mean that we shouldn't even test a configuration that fails the
schedulability test? As I recall, these tests can be pretty
conservative. (I don't know what the right answer is here, I'm just
askin'....)

> I also believe that an appropriate run-time infrastructure 
> is needed to (a) schedule the various processes/threads to 
> meet their deadlines when run concurrently 

Is is possible that we will have certified a configuration without
knowing how to schedule it? That would mean that we somehow have
established (to within reasonable certainty) that the configuration can
be scheduled, but we don't know a schedule for it. Is that possible?
Well, he said answering his own question, in very relaxed circumstances
(not too much processing going on) it is possible to know that a
schedule exists without constructing one. But in this case the run-time
schedule construction is pretty easy, isn't it?
 
> ...(b) enforce/isolate the run-time behaviors of each 
> process/thread, 

Totally agree. This kind of isolation will be key to our 'projection'
operation.

> ...and (c) the policies/mechanisms of the 
> run-time infrastructure should match the assumptions of the 
> bin-packing phase.  

If I might insert a step, how about: The policies/mechanisms of the
configuration construction machinery [which includes bin-packing] should
match those of the test environment, and the policies/mechanisms of the
test environment should match those of the run-time infrastructure.

- Joe