COSC 4330                   QUIZ #2                     August 6, 1998

Closed Book.   You can have one sheet of notes.

1.   Complete the following sentences: (4×10 points)

     In a remote procedure call, arguments cannot be passed by
      ______________________________________.

     The initial value of a mutual exclusion semaphore is always ______.

     A  missing ___________________ operation on a semaphore is likely to
     result in a deadlock.

     The   ____________________________________________  semantics  means
     that each request will either be fully executed or have no effect.


2.   What can be done to deny the circular wait condition?  Give  one
     example where it does not. work.  (2×10 points)
    
3.   What is wrong with the following solution to the mutual exclusion
     problem? Check all that apply(4×5 points)
  
       int status = 1;
       
       // Enter Critical Section
       while (status == 0);
            status = 0;
       Critical_Section;
       //Leave Critical Section
       status = 1;
       
  O    it does not guarantee mutual exclusion,

  O    it may prevent some processes from entering the critical section
      while no other process is inside,

  O    it can cause deadlocks,

  O    it can cause starvation.

4.   What is the difference between a signal and a notify? (20 points)
--IMPORTANT----IMPORTANT----IMPORTANT----IMPORTANT----IMPORTANT--
Please do not try to answer these questions by yourself BEFORE
having a clear idea of what's on the test for which you are
studying.

Materials covered in each test DO VARY from semester to semester
because the pace of the course can change, some materials are be
added and other deleted almost every semester.
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