Device Management & Deadlock Operating Systems Device Management & Deadlock 1) These notes are © Aiman Hanna. All copyrights reserved. For more information please e-mail to: Contact@AimanHanna.com. 2) These notes are also based on: Operating Systems, 3rd edition by Garry Nutts, published by Addison Wesley, ISBN-10: 0201773449 | ISBN-13: 9780201773446 . 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

Optimizing Access to Magnetic Disks FCFS SSTF Scan/Look Circular Scan / Circular Look Homing Instructions

Deadlock Why is Deadlock deadly? Resource Allocation Graph What would a loop in the resource allocation graph indicate? What if there are no loops?

Deadlock Needed Conditions for deadlock to occur Deadlock Prevention Different ideas to violate one of the needed 4 conditions of deadlock and so prevent deadlock Was any of these ideas possible? Deadlock avoidance Deadlock Detection & Handling If none of the above is possible, what can an OS do?

Where is this week coverage in the textbook? Device Management Chapter 5 – Pages 180 through 185 Deadlock: Study form the notes provided in class.  Note: If you did not come to class and did not obtain these notes from me afterwards, then you must read chapter 10 in your textbook as best alternative