Week 12 Flashcards
1
Q
Each process utilizes a resource as follows:
A
- Request, Use, Release
2
Q
A deadlock can arise if four conditions hold simultaneously
A
- Mutual Exclusion: Only one process at a time can use a resourcer
- Hold and wait: A process holding at least one resource is waiting to acquire additional resources held by other proccesses
- No preemption: a resource can be released only voluntarily by the process holding it, after that process has completed its task
- Circular wait: there exists a set of processes that are all waiting on each other thus creating a circle
3
Q
What is deadlock prevention
A
- provides a set of methods to ensure that at least one of the necessary conditions can not hold
4
Q
What is Deadlock avoidance
A
- requires that the operating system be given additional information in advance concerning which resources a process will request and use during its lifetime
5
Q
What is a safe state?
A
If a system is in safe state = no deadlocks otherwise there is a possibility of deadlock
6
Q
What is the Banker’s Algorithm
A
- When a new process enters the system, it must declare the maximum number of instances of each resource type that it may need
- The number can’t exceed the total number of resources in the system.
7
Q
What are the data structures for the Banker’s Algorithm
A
- Available, Max, Allocation, Need
