Assignment 12, due July 29

Assignment 12, due July 29

1. Do problem 1 from chapter 16 of the notes (and note the similarity to the final problem in chapter 15).

2. Consider two fictional processors, X and Y (very creative names):
   • Processor X has 1000 general purpose registers

   • Processor Y is as nearly similar to X as possible except for having only 8 general purpose registers and has 992 words of cache, plus (unstated) other changes that are a consequence of this.

   Which machine would you expect to have a faster context switching time, and why?

3. Take a look at http://homepage.cs.uiowa.edu/~dwjones/opsys/threads/source.txt and find the code for thread_relinquish(). This code is the core of the scheduler for a thread manager that works for C programs. Then, look at the documentation for setjmp and longjmp from the standard C library (use man or Google).

   What information must be stored in the jump buffer for this approach to writing a thread manager to work? Relate this to concepts in both computer architecture and programming language implementation.

4. When should you use semaphores for mutual exclusion, and when should you use spin-locks. Does this depend on how many CPUs you have in your computer system?