39.How can the priority of a thread be set in Java?

40.Can Java threads be actor threads, server threads, or either?

41.Describe the actions of the three Java methods that are used to support cooperation synchronization.

42.What kind of Java object is a monitor?

43.Explain why Java includes the Runnable interface.

44.What are the two methods used with Java Semaphore objects?

45.What is the advantage of the nonblocking synchronization in Java?

46.What are the methods of the Java AtomicInteger class and what is the purpose of this class?

47.How are explicit locks supported in Java?

48.What kinds of methods can run in a C# thread?

49.Can C# threads be actor threads, server threads, or either?

50.What are the two ways a C# thread can be called synchronously?

51.How can a C# thread be called asynchronously?

52.How is the returned value from an asynchronously called thread retrieved in C#?

53.What is different about C#’s Sleep method, relative to Java’s sleep?

54.What exactly does C#’s Abort method do?

55.What is the purpose of C#’s Interlocked class?

56.What does the C# lock statement do?

57.On what language is Multilisp based?

58.What is the semantics of Multilisp’s pcall construct?

59.How is a thread created in CML?

60.What is the type of an F# heap-allocated mutatable variable?

61.Why don’t F# immutable variables require synchronized access in a multithreaded program?

62.What is the objective of the specification statements of HighPerformance Fortran?

63.What is the purpose of the FORALL statement of High-Performance Fortran and Fortran?

P R O B L E M S E T

1.Explain clearly why competition synchronization is not a problem in a programming environment that supports coroutines but not concurrency.

2.What is the best action a system can take when deadlock is detected?

3.Busy waiting is a method whereby a task waits for a given event by continuously checking for that event to occur. What is the main problem with this approach?

4.In the producer-consumer example of Section 13.3, suppose that we incorrectly replaced the release(access) in the consumer process with wait(access). What would be the result of this error on execution of the system?

5.From a book on assembly language programming for a computer that uses an Intel Pentium processor, determine what instructions are provided to support the construction of semaphores.

6.Suppose two tasks, A and B, must use the shared variable Buf_Size. Task A adds 2 to Buf_Size, and task B subtracts 1 from it. Assume that such arithmetic operations are done by the three-step process of fetching the current value, performing the arithmetic, and putting the new value back. In the absence of competition synchronization, what sequences of events are possible and what values result from these operations? Assume that the initial value of Buf_Size is 6.

7.Compare the Java competition synchronization mechanism with that of Ada.

8.Compare the Java cooperation synchronization mechanism with that of Ada.

9.What happens if a monitor procedure calls another procedure in the same monitor?

10.Explain the relative safety of cooperation synchronization using semaphores and using Ada’s when clauses in tasks.

P R O G R A M M I N G E X E R C I S E S

1.Write an Ada task to implement general semaphores.

2.Write an Ada task to manage a shared buffer such as the one in our example, but use the semaphore task from Programming Exercise 1.

3.Define semaphores in Ada and use them to provide both cooperation and competition synchronization in the shared-buffer example.

4.Write Programming Exercise 3 using Java.

5.Write the shared-buffer example of the chapter in C#.

6.The reader-writer problem can be stated as follows: A shared memory location can be concurrently read by any number of tasks, but when a task must write to the shared memory location, it must have exclusive access. Write a Java program for the reader-writer problem.

7.Write Programming Exercise 6 using Ada.

8.Write Programming Exercise 6 using C#.