Operating Systems Discussion

Avoiding Deadlock

Part 1: Discussion Post

Some kernel experts have the view that the best way to deal with deadlock is to avoid it altogether. Discuss impacts / pros / cons of this approach.

Part 2: Reply to two peer posts

Peer 1 Megan

When we talk about avoiding deadlock we are talking about avoiding one of the instances that can lead to a deadlock. This isn't necessarily going to be able to happen. the algorithm for avoiding deadlock looks at creating a safe state and an unsafe state. Once a certain amount of resources has been allocated the system may send back an unsafe signal. At that point, no more resources will be allocated until more have been freed. The cons to avoiding deadlock are that each job has to state what it needs before proceeding, the number of jobs has to be a fixed number, resources aren't being allocated efficiently, and scheduling suffers. Each of these cons leads to a high overhead on the system's part because the information has to be tracked.

Peer 2 Reese

As our textbook discusses in the reading this week, deadlocks, for the most part, can be an inconvenience, but in real time systems like aircraft, automated cars, or a hospitals life support system a deadlock of the system can potentially cause loss of life.  One other impact that really wasn’t discussed in our text is customer satisfaction of the product.  If you have a system that always crashes like the Blue Screen of Death eventually customers will look at other solutions.  As someone who travels on airplanes very often and who work computer-controlled weapons systems, I am very thankful for systems that do not crash due to deadlock, and I think that is a huge pro.  Some of the cons to total deadlock avoidance are potentially high overhead, and resources are not utilized in an efficient manner.