UNIVERSITY OF HOUSTON
                  Department of Computer Science
                   COSC 6360: Operating Systems
                             MIDTERM
                         March 21,  1991

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

1.   What were the major limitations of the Version 7 implementation of
     the UNIX file system?  (10 points) What were the major
     improvements brought by Berkeley 4.2? (10 points)

2.   Contrast the ways MULTICS and UNIX implement directories. (6
     points) Which implementation is better? Why? (4 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 are the differences between a STREAM socket and a DATAGRAM
     socket? (10 points)

     BSD IPC WAS TREATED IN MUCH GREATER DETAIL THAT SEMESTER

4.   In the Berkeley IPC model, what is happening when a server process
     executes an accept? (10 points)

     BSD IPC WAS TREATED IN MUCH GREATER DETAIL THAT SEMESTER

5.   Explain how file descriptor passing can simplify the establishment
     of a network connection in the Ninth Edition Unix System. (20
     points)

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

6.   Which of the following features of the Mach OS were already present
     (even under another name) in the MULTICS virtual memory system?
     (15 points)

      Copy-on Write:
      External Pagers:
      Memory Objects:
      Read-Write Shared Memory:
      Shared Libraries:

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

7.   Describe the steps taken by MULTICS to resolve a segment fault
     for an ACTIVE segment that is already KNOWN to the process
     attempting to access it and explain at every step where the
     required information is to be found.  (15 points)

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