PPT-Deadlocks

Detection and Avoidance Prof Sirer CS 4410 Cornell University System Model There are nonshared computer resources Maybe more than one instance Printers Semaphores Tape drives CPU Processes need access to these resources. icssaitamauacjp Abstract This article presents some examples of tasking deadlocks concerning tasking synchronization waiting relations de57519ned in Ada 95s RealTime Systems Annex 1 Introduction A tasking deadlock in a concurrent Ada program is a sit icssaitamauacjp Abstract This article presents some examples of tasking deadlocks concerning tasking synchronization waiting relations dened in Ada 95s RealTime Systems Annex 1 Introduction A tasking deadlock in a concurrent Ada program is a situatio 1 List three examples of deadlocks that are not related to a computer system environment Answer Two cars crossing a singlelane bridge from opposite directions A person going down a ladder while another person is climbing up the ladder Two trains tr 1 List three examples of deadlocks that are not related to a computer system environment Answer Two cars crossing a singlelane bridge from opposite directions A person going down a ladder while another person is climbing up the ladder Two trains Chapter 7: Deadlocks. The Deadlock Problem. System Model. Deadlock Characterization. Methods for Handling Deadlocks. Deadlock Prevention. Deadlock Avoidance. Deadlock Detection . Recovery from Deadlock . What is it?. What is concurrency?. Concurrency is not a new idea…. Concurrency was first developed by the ancient Babylonians.. They thought about stuff, walked, and chewed gum … all at the same time.. 1. 6. Deadlocks. 6.1 Deadlocks with Reusable and Consumable. . Resources. 6.2 Approaches to the Deadlock Problem . 6.3 A System Model . Resource Graphs . State Transitions. Deadlock States and Safe States . 1. 7.1 System Model. In order to talk about deadlocks in a system, it’s helpful to have a model of the system. A . system consists of a set of resources. The resources can be grouped into types. Processes compete to have (unique) access to instances of the types. DEADLOCKS. To be discussed…. Definition of deadlock. Example of deadlock. Resource allocation graph. Strategies to handle deadlock. - . Deadlock Prevention. - . Deadlock Avoidance. - . Dynamics NAV system’s performance. Hynek Muhlbacher. Ludo Van den Ende. SQL Perform. 2. Passionate about your system performance!. 3. SQL Perform Partners. 4. And many more! . Apologies to the ones being here and not being on the slide!. 1. 7.1 System Model. A system consists of a set of resources. The resources can be grouped into types. Processes compete to have (unique) access to instances of the types. 2. Examples of resource types:. Deadlock . detection. Resource Allocation Graphs. Resource Pool and . C. ounting Semaphores. Dining . Philosophers Problem. Condition Variables . Resource Tables. Deadlock Definition. A . deadlock.  is a situation in which two or more competing actions are each waiting for the other to finish, and thus neither ever does. “A set of processes is deadlocked if each process in the set is waiting for an event that only another process in the set can cause.”. Detection. “Is this system deadlocked, and if so, which processes are involved?”. OPERATING SYSTEMS . DEADLOCKS. 7: Deadlocks. 2. What Is In This Chapter?. What is a deadlock?. Staying Safe: Preventing and Avoiding Deadlocks. Living Dangerously: Let the deadlock happen, then detect it and recover from it..