1. Basic Synchronization Principles
Operating Systems
Basic Synchronization Principles
1) These notes are © Aiman Hanna. All copyrights reserved. For more information please to:
2) These notes are also based on: Operating Systems, 3rd edition by Garry Nutts, published by Addison Wesley, ISBN-10: | ISBN-13: These notes still totally enforce all copyrights for Nutts/ Addison Wesley. For more information on these rights, please refer to the original publication of the book.
3) VERY IMPORTANT: These notes are neither complete nor sufficient to study for the course. They are merely given so that you can follow the covered subjects. You should NEVER depend solely on these notes for your study.
Any use of these notes that results in violation of any of the copyrights indicated above is strictly prohibited.
© Dr. Aiman Hanna
Department of Computer Science Concordia University Montreal, Canada
Data Communications & Computer Networking, by: Aiman Hanna

2. Critical Sections (CSs)
What are they?
Examples of what may happen if CSs are not handled with care
Examples of cooperating processes around CSs

3. Enabling/Disabling Interrupts
Will they provide a solution to the CS problem?
If yes, why cannot we depend on this solution then!

4. Other Solutions to the CS Problem
Acquiring a lock for example
How can the lock be obtained and released correctly?
Examining different solutions and see why they may fail/work.

5. Protecting Different CSs
Should one lock be used to protect different CSs?
Why/Why not?

6. Deadlock
What is it?
Why is it deadly?

7. Evolving the CS solution
Use of FORK/JOIN
Synchronization

8. Concurrent Processes
Synchronization between concurrent processes to achieve proper behavior

9. Semaphores What is a semaphore? How can they be used to achieve:
Protection of CSs - Mutual Execution
Proper synchronization/communication between concurrent processes

10. Where is this week coverage in the textbook?
Chapter 8:
Sections 8.1, 8.2 & 8.3 (until page 310), with the following exceptions:
Skip: Figure 8.1 and Figure 8.2. This material however will be covered as part of the programming assignment.