UNIVERSITY OF HOUSTON
                    Department of Computer Science

                     COSC 6360: Operating Systems
                          FINAL EXAMINATION
                      Part I: General Questions
                       QUALIFYING  EXAMINATION 
                       Part A: Graduate Topics
                            May 16, 1991

CLOSED BOOK:  You may have with you two sheets of notes.

1.   What can be done to reduce the overhead of Remote Procedure Calls?
     (20 points)

2.   How would you implement replicated files in a distributed file 
     system supporting the IMMUTABLE SHARED FILE SEMANTICS?  Describe
     in some detail (a) your definition of the most current version of
     a file, (b) your treatment of network partitions, and (c) your
     implementation of replicated directories.

                        UNIVERSITY OF HOUSTON
                    Department of Computer Science

                     COSC 6360: Operating Systems
                          FINAL EXAMINATION
                     Part II:  Specific Questions
                            May 16,  1991

CLOSED BOOK: You may have with you two sheets of notes.

1.   What makes CONDITIONAL CRITICAL REGIONS impossible to implement
     efficiently? (10 points)

2.   Would it be a good idea to implement ALL Remote Procedure Calls as
     ATOMIC TRANSACTIONS?  Why?  (10 points)


3.   Why are GUARDED COMMANDS an ESSENTIAL part of CSP's design?  (6
     points)  How do UNIX IPC packages solve the same problem? (4 
     points)

4.   What are the advantages and disdavantages of Andrew's CALLBACK
     mechanism? (10 points)

6.   (a)  What are the major limitations of Sun's NFS in terms of
          administrative complexity, performance and sharing semantics?
          (8 points)

     (b)  How does SPRITE solves these problems? (10 points)

     (c)  Give ONE major weakness of SPRITE? (2 points)