Priority Ceiling Protocol totally eliminates deadlock

[Oyvind Teig <Oyvind.Teig@xxxxxxxxxxxx>]

In "Doing Hard Time" - Developing Real-Time Systems with UML,
Objects, Frameworks, and Patterns by Bruke Powel Douglass, p.563
the author states this.

When he comes to the Priority Ceiling Protocol he says that it 
"totally eliminates deadlock". 

Previously he has limited context to "priority-based" and 
"preemptive scheme", (p561) and problems with not-paired 
ordering of nested acquirement of locks (p562). 

Q1. I seem to remember that nested ACQUIRE should not be legal
    in occam 3. This should also "totally eliminate dedalock", eh?
Q2. In _this_ sense CSP is also totally elmininated from deadlocks,
    since he seems not to talk about pathological communication
    paths between processes, but wrongly used locking primitives?
Q3. Is it at all correct to limit deadlock discussion this much,
    without making clear that process deadlocks are not discussed?
Q4. Have I misunderstood everything in the sense that he really is
    _also_ talking about user process deadlocks?
Q5. With the occam3 solution, I conclude that preemption does not
    have anything to do with this. Still the authror's discussion
    mentions preemptions so much that I don't know. Is preemption
    vs. f.ex. non-preemptive schemes essemtial for this discussion?

-- 

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