CMSC 714 Midterm (similar to prior Sussman/Hollingsworth exams, but more
questions)

(1)  This exam is closed book, closed notes, and closed neighbor.

(2) You have 75 minutes to complete this exam.  If you finish early, you
    may turn in your exam at the front of the room and leave.  However if
    you finish during the last ten minutes of the exam please remain seated
    until the end of the exam so you don't disturb others.
	
(3) Partial credit will be given for most questions assuming I can figure
    out what you were trying to do.
	
(4) Please write neatly. Print your answers if your handwriting is hard to
    read. If you write something, and wish to cross it out, simply put an X
    through it.

1.	 Define and explain the following terms:
A.	 Vector Processor
B.	 Causal Ordering
C.	 Reduction Operation
D.	 Space Sharing

2.	 Several of the parallel computers we looked at this
         semester provided globally shared memory but lacked cache
         coherence.
A.	 What were two of these systems?
B.	 What are the implications of having such an architecture on the
	 programmer and programming model (for example which of the models
	 we looked at would be well suited for this type of machine)?

3.	 The Valgrind and Dyninst systems each are designed to
         modify compiled programs.  Compare and contrast how the tools work and
	 their various features.

4.	Some proponents of shared memory programming models
        claim the major advantage of shared memory over message passing is that
	you don't have to worry about where your data is located since all
        memory is shared. Explain why this assumption is naive if
        performance matters.

5.	The Eraser system uses the lockset algorithm to find
	synchronization problems.
A.	Will the system find all races in a program (explain your answer)?
B.	Explain how and why a finite state machine is maintained per variable.