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From: Alexander Terekhov (terekhov_at_[hidden])
Date: 2003-06-10 10:14:55

"Victor A. Wagner, Jr." wrote:
> well, unless (likely given this biz) the words have changed meaning again,
> "naked semaphore" was described by Dijkstra way back when (1964??)

But just a few years later (in 1971) Sir Tony Hoare (ironically, his
"current" homepage is @ <>)
wrote the following in the ACKNOWLEDGMENTS section of his paper named

 It will be obvious to all how much this paper owes to the thought
 and writings of Professor E. W. Dijkstra, to whom I owe the concept
 of the critical region, and the semaphore, the deadly embracy and
 Less obvious but equally invaluable has been his constant
 encouragement in the search for a concept to 'replace' the semaphore
 ..." ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

> btw, note that IF my definition is correct, then at a minimum a mutex must
> do more work than a semaphore (since it must establish "ownership" of the
> mutex).

That's needed for recursive or error-check mutexes and things like
"priority inheritance" protocol to fight the problem of unbounded
priority inversion in the "realtime" appls. It isn't needed for the
"normal" mutexes with or without "priority protection" protocol.


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