Computer Science 322
Operating Systems

• Announcements
  • CPU scheduling lab updated due dates
  • Take-home exam after break. Tentative schedule: out during class Wednesday 3/24, due back Friday 3/26.
• The Critical Section Problem
• Software solutions for 2 processes
• Bakery Algorithm
• Hardware support for process synchronization
  • atomic test-and-set
  • bounded wait using atomic test-and-set

Due at the start of class, Wednesday, March 10.

Please submit answers to these questions either as a hard copy (typeset or handwritten are OK) or by email to jteresco AT mtholyoke.edu by the start of class. We will discuss these questions at the start of class, so no late submissions are accepted.

• SG&G Exercise 6.9, p. 268-269.
• SG&G Exercise 6.11, p. 269.
• Write a C program that will list all possible orderings of the machine instructions generated for the critical sections of the Producer-Consumer example from class. Recall that the statements counter++ and counter-- actually generate machine code such as

  	Producer		Consumer
  P1	R0 = counter;	C1	R1 = counter;
  P2	R0 = R0 + 1;	C2	R1 = R1 - 1;
  P3	counter = R0;	C3	counter = R1;

  Your program should list all possible interleavings of the statements P₁, P₂, P₃, C₁, C₂, and C₃. Also have your program print which interleavings produce a correct result (that counter has the same value it started with).

  Write your program in a file called interleaving.c.