Department of Computer Science
                                
                  COSC 6360--Operating Systems
                       MIDTERM EXAMINATION
                          March 5, 1996
                                
     This exam is closed book.  You can have two sheets (i.e., four
     pages) of notes.

1.   What is a superblock? (4 points)  What does Berkeley UNIX to
     protect superblocks against disk failures and why? (6 points)
         
2.   What made the UNIX toolkit approach so successful at the
     beginning? (5 points)  Which problems does it encounter now that
     we are in the age of graphical and WYSIWYG applications?(5
     points) (Hint:  Think about applications of pipes.)
  
3.   Describe the VMS page replacement policy (10 points) and
     explain which of its features made it particularly ill-suited for
     UNIX ( 5 points)

4.   In Satyanarayanan’s Lightweight Recoverable Virtual Memory,
     what is ano_flush transaction?  (4 points) What are their major
     advantage ( 3 points) and disadvantage (3 points)

5.   What is inheritance in Mach? (5 points)  At which level is
     it defined?  (5 points)  Explain how Mach uses it to support both
     regular and lightweight processes.  (10 points)(Hint:  Do not
     forget mapped files.)

6.   According to Talluri et al. what is the difference between
     superpages and subblocks? (5 points)

7.   Which events trigger upcalls in scheduler activations?  (10
     points)

8.   In Birrell and Nelson’s implementation of remote procedure
     calls, what is happening when the calling process does not
     receive promptly a result message?  (5 points)  What will happen
     later if the result message continues to be delayed?  (5 points)

9.   What is the main purpose of a shuttle in the Spring Kernel?
     (10 points)
     
     
     
     
     
     
     
     
     
     
     
     
     
     
10.
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
                      UNIVERSITY OF HOUSTON
                 Department of Computer Science
                                
                  COSC 6360--Operating Systems
                       MIDTERM EXAMINATION
                          March 5, 1996
                                
This exam is closed book.  You can have two sheets (i.e., four
     pages) of notes.

1.   What made the UNIX toolkit approach so successful at the
     beginning? (5 points)  Which problems does it encounter now that
     we are in the age of graphical and WYSIWYG applications?(5
     points) (Hint:  Think about applications of pipes.)
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
2.   What is a superblock? (4 points)  What does Berkeley UNIX to
     protect superblocks against disk failures and why? (6 points)
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
3.   What is a no_flush transaction in Satyanarayanan’s
     Lightweight Recoverable Virtual Memory,?  (4 points) What are
     their major advantage ( 3 points) and disadvantage (3 points)
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
4.   Describe the VMS page replacement policy (10 points) and
     explain which of its features made it particularly ill-suited for
     UNIX ( 5 points)
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
5.   What is inheritance in Mach? (5 points)  At which level is
     it defined?  (5 points)  Explain how Mach uses it to support both
     regular and lightweight processes.  (10 points)(Hint:  Do not
     forget mapped files.)
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
6.   Which events trigger upcalls in scheduler activations?  (10
     points)
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
7.   According to Talluri et al. what is the difference between
superpages and subblocks? (5 points)
8.   What is the main purpose of a shuttle in the Spring Kernel?
(10 points)
9.   In Birrell and Nelson’s implementation of remote procedure
     calls, what is happening when the calling process does not
     receive promptly a result message?  (5 points)  What will happen
     later if the result message continues to be delayed?  (5 points)