1. Multithreaded Programming ( 4.1-4.3)

2. Components of a Process Figure 3.1

3. Multi-programming Systems Kernel

4. Single vs Multithreaded Processes Figure 4.1

5. Multi-programming Systems (with threads) Kernel

6. Demo – Spiral Turtles

7. Demo – Turtles’ speed limit Write the program that does the following:  Turtle 1 moves forward every 3 seconds  Turtle 2 moves forward every 5 seconds Compare using variables to count time vs using threads

8. Thread Example I: Modular Design Main Thread Screen Updater UI Monitor & Update Communications Handler Process

9. Thread Example II: Web Server Main Server Thread User Thread 1 Server Process User Thread 2 User Thread 3

10. Benefits of Multithreaded Programming Responsiveness Threads don’t block each other Resource Sharing Can access same resources Economy Cheaper to create a new thread Utilization of Multi-processors Program runs faster

11. Multithreading Modes User Threads: Thread management done in the user program (not the OS).  Ex. Python Kernel Threads: The OS handles thread management.  Ex. Java

12. Many-to-One Model Green Threads Portable Threads (pthreads) Figure 4.2

13. One-to-One Model Windows NT/XP/2000 Linux Solaris 9 and later Figure 4.3

14. Many-to-Many Model Figure 4.4

15. Two-level Model  Solaris < version 9  IRIX  HP-UX  Tru64 UNIX Figure 4.5