UNIVERSITY OF HOUSTON
                 Department of Computer Science

          COSC 4330: Fundamentals of Operating Systems
                   SECOND MIDTERM EXAMINATION
                        November 12, 1992

CLOSED BOOK: You are allowed one 8.5 by 11" sheet of notes.

1.   What is a rendez-vous between two processes?  (10 points)

     Write the code for a  rendez-vous  using  only  non-blocking
     writes and blocking receives  (10 points)

     Process One:                  Process Two:

2.   What is the major limitation of UNIX pipes? (10 points)

3.   What are the functions performer by the  client  stub  in  a
     remote procedure call? (20 points)

4.   What is the  major  advantage  of  assigning  priorities  to
     processes waiting for the CPU?   (10 points)

     Which processes should be  given  the  lowest  priority?  (5
     points)

5.   The workload of a workstation  consists  of  processes  that
     spend  50%  of their time waiting for I/O.  What will be the
     average CPU  utilization  if  the  average  multiprogramming
     level is equal to three? (5 points)

6.   A computer has a maximum memory size of 256 Megabytes.   The
     memory  is  byte  addressable  and  virtual  addresses  have
     thirty-two (32) bits.

     Given a page size of two (2) Kilobytes, what are

     (a)    the number of page frames in physical memory?       frames

     (b)    the maximum number of entries in a page table?      entries

     (c)    the number of bits in a page number?                bits

     (d)    the number of bits in a page frame number?          bits

     (4 x 5 points)

7.   What is the essential difference between a monitor condition
     and a semaphore? (10 points)


--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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