Answers to the Exercises
========================

6.8
===

    a. The shortest job has the highest priority. So SJF is 
       a special case of Priority Scheduling. 
    b. The lowest level of MLFQ is a FCFS Scheduling. That is the 
       algorithm used in the lowest queue of MLFQ is FCFS.
    c. FCFS gives the highest priority to the job having been in existence 
       the longest. So FCFS is a special case of Priority Scheduling where 
       the priority is the length of the job.
    d. Both attempt to get the shortest job out of the system first. 


9.8
===
    
     a. 13 bits, 3 for the 2^3 page numbers, 
        and 10 for the 2^10 words within pages.
     b. 15 bits, 5 for the 2^5 frame numbers, 
        and 10 for the 2^10 words within frames.  


9.14
====

        Since segmentation is based on a logical division of memory rather 
        than a physical one, segments of any size can be shared with only 
        one entry in the segment tables of each user. With paging there must 
        be a common entry in the page tables for each page that is shared. 
 

10.12
=====

        You can use the valid/invalid bit supported in hardware to simulate 
        the reference bit. Initially set the bit to invalid. On first 
        reference a trap to the operating system is generated. The operating 
        system will set a sofware bit to 1 and reset the valid/invalid bit 
        to invalid.