COSC 4330                   QUIZ #1                   February 3, 1997


Closed Book.   You can have one sheet of notes.  Each question is
worth 20 points.

1.   True or False

T ___  F ___   Most of the kernel code of the UNIX operating system is
               written in Modula-2.

A:  FALSE (IT WAS WRITTEN IN C)

T ___  F ___  In a time-sharing system, each user has his or her own 
              workstation but all share the same file server and the 
              same printer.

A: FALSE (IN A TIME SHARING SYSTEM, THE USERS SHARE THE SAME 
   COMPUTER)

2.   What is the correct way to handle interrupts that occur while the
     system is already busy handling another interrupt?

A:   EACH CLASS OF INTERRUPTS SHOULD BE ALLOCATED A PRIORITY LEVEL.
     INTERRUPTS WHOSE PRIORITY LEVEL IS HIGHER THAN THAT OF THE 
     CURRENT INTERRUPT SHOULD BE HANDELED IMMEDIATELY; OTHERS WOULD
     HAVE TO WAIT
 
3.   What are the two major benefits of memory protection?

A:   1.  USER PROCESSES CANNOT ACCESS THE KERNEL MEMORY ADDRESS SPACE
         AND MODIFY THE KERNEL CODE

     2.  USER PROCESSES CANNOT ALTER THE ADDRESS SPACES OF OTHER
         PROCESSES (AND CRASH THEM)
  
4.   What is the major advantage of a symmetric organization for
     multiprocessor operating systems?

A:   IN A SYMMETRIC ORGANIZATION, THE KERNEL CAN RUN ON ANY 
     PROCESSOR (INSTEAD OF A SINGLE DESIGNATED "MASTER" PROCESSOR).
     HENCE THIS SINGLE MASTER PROCESSOR CANNOT BECOME  A
     BOTTLENECK

5.   How  did graphical user interfaces contribute to the success of
     workstations?

A:   A GUI REQUIRES A GRAPHICAL DISPLAY.  SINCE MUCH MORE
     MORE INFORMATION HAS NOW TO CIRCULATE BETWEEN THE COMPUTER
     AND THE USER DISPLAY, IT BECAME NECESSARY TO PUT THE PROCESSOR
     IN THE SAME "BOX" AS THE USER TERMINAL.  THE WORKSTATION WAS
     BORN.

     ONE COULD ALSO SAY THAT GUI WERE EASIER TO USE AND INCREASED
     THE NUMBER OF PEOPLE CAPABLE TO USE A WORKSTATION EFFECTIVELY
     BUT ONE COULD THEN COUNTERARGUE THAT NON-SPECIALISTS WERE
     ALREADY USING pc'S RUNNING MS-DOS IN THE 80'S AND THESE
     MACHINES DID NOT HAVE A GUI.


--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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