Reading Assignment

• Operating Systems Concepts: Chapter 4.

Lecture Slides

• Threads

Homework Assignment

Due Date: 3/17/08


• Operating Systems Concepts: #4.3, #4.4, #4.5.
• Write a Java program that takes two integers as command line parameters and computes the summation of all of the integers from the first parameter up to but not including the second. For example if the parameters were 100 and 8000 then the program would add up all of the integers from 100 up to but not including 8000. Your program must divide the work of computing the summation up among 4 concurrently executing threads. Each thread should compute the summation for approximately 1/4 of the range of numbers and store the result in the shared address space. The main thread must wait for all 4 threads to complete. When the threads are complete the main thread must compute the final result by adding up the partial results generated by the threads and display it on standard output.
• Under what circumstances would the program you just wrote run more quickly than a single threaded solution that did all of the computation in main?

Related Web Sites

Threads: Doing Two Or More Tasks At Once

A set of pages from the Java Tutorial that discuss how to create and use threads. Some of this goes well beyond what we'll be doing in this class, but the inroductory material is good.

Sample Code

• FirstThread.java - Example of creating a Thread in Java.
• ConcurrentThreads.java - Example demonstrating the concurrent execution of threads in Java.
• YieldJoin.java - Example showing the use of the yield and join methods in Java.
• SharedAddressSpace.java - Example demonstrating that all threads share a common address space.

Acknowledgment: this content is essentially identical to that developed by Professor Grant Braught for the Spring 2006 Operating Systems course, and I'm grateful for his permission to use it.