UNIVERSITY OF HOUSTON
                 Department of Computer Science
                                
                  COSC 6360--Operating Systems
                       MIDTERM EXAMINATION
                         March 28, 1994

This exam is closed book.  You can have two sheets (i.e. four
pages) of notes.

1.   Describe the major differences between the ways MULTICS
     segments and UNIX files are stored on disk.  You don't have
     to discuss UNIX special files nor UNIX access control lists.
     (20 points)

     THIS QUESTION WAS RELATED TO A PAPER THAT IS NOT ANYMORE IN THE
     READING LIST.  IT WILL BE NOT BE ASKED AGAIN.

2.   Which steps are taken by the MULTICS supervisor when it
     activates a segment? (10 points)

     THIS QUESTION WAS RELATED TO A PAPER THAT IS NOT ANYMORE IN THE
     READING LIST.  IT WILL BE NOT BE ASKED AGAIN.

3.   What makes a fork() system call so costly? (5 points)  Which
     steps are taken by (a) Berkeley UNIX (5 points) and (b) MACH
     (5 points) to make forks less costly?

4.   Which considerations motivated the introduction of a guarded
     command in Hoare's CSP language? (10 points)

5.   What are the major issues in the passing of parameters in
     Remote Procedure Calls (20 points)

6.   What did Birrell and Nelson do to reduce process creation
     costs  in their remote procedure call package?  (5 points)
     What would have been an even better  solution?  (5 points)

7.   According to Bershad et al., what is an upcall ?  (5 points)

8.   Describe the exchange of messages between a client
     workstation and the Kerberos server at login and explain the
     contents of each message.  (10 points)