Question 1

Describe how a safe state ensures deadlock will be avoided.

Accepted Answer

A safe state ensures that there is a seq...

Question 2

Deadlock prevention using preempting allocated resources cannot be used for

Accepted Answer

A)   mutexes.
B)   CPU registers.
C)   database transactions.
D)   memory.E) A) and B)
F) All of the above

Question 3

What does a claim edge signify in a resource-allocation graph?

Accepted Answer

A claim edge indicates that a process may request a resource at some time in the future. This edge resembles a request edge in direction, but is represented in the graph by a dashed line.

Question 4

Recovery from a deadlock works best when a single process can be identified whose termination will break the circular wait.

Accepted Answer

A) True 
 B)False

Question 5

The Linux Lockdep tool is

Accepted Answer

A)   used to verify locking order in the kernel.
B)   a modeler to develop resource allocation graphs
C)   a driver that can be used to prevent mutual exclusion for nonsharable resources
D)   an implementation of the banker's algorithm available for most operating systemsE) B) and C)
F) C) and D) A

Question 6

One necessary condition for deadlock is ______, which states that a resource can be released only voluntarily by the process holding the resource.

Accepted Answer

A)   hold and wait
B)   mutual exclusion
C)   circular wait
D)   no preemptionE) B) and D)
F) B) and C)

Question 7

Describe two protocols to ensure that the hold-and-wait condition never occurs in a system.

Accepted Answer

One protocol requires each process to re...

Question 8

Ordering resources and requiring the resources to be acquired in order prevents the circular wait from occurring and therefore prevents deadlock from occurring.

Accepted Answer

A) True 
 B)False

Question 9

Suppose that there are two resource types (R1 and R2)  with five resources each available to four processes. At time 0, the following data is collected. The table indicates the process, the number of resources of each type currently allocated to the processes, and the current request of each resource type by each process. Process Allocation Request
R1 R2 R1 R2
P0 2 0 3 2
P1 1 1 1 0
P2 0 1 1 1
P3 1 1 3 2
Which of the following sentences is correct?

Accepted Answer

A)   All four processes are currently deadlocked.
B)   The system is not deadlocked.
C)   Processes P0 and P3 are deadlocked.
D)   Processes P0, P1 and P3 are deadlocked.E) A) and B)
F) All of the above

Question 10

A _____ could be preempted from a process.

Accepted Answer

A)   mutex lock
B)   CPU registers
C)   semaphore
D)   file lockE) None of the above
F) All of the above

Question 11

If the sum of all needs for a resource type exceeds the available number of instances of that resource type, the system state is unsafe.

Accepted Answer

A) True 
 B)False

Question 12

In a resource allocation graph, when a process releases a resource,

Accepted Answer

A)   a request edge is inserted.
B)   an assignment edge is inserted.
C)   a request edge is removed.
D)   an assignment edge is removed.E) A) and B)
F) A) and C)

Question 13

What is the difference between deadlock prevention and deadlock avoidance?

Accepted Answer

Deadlock prevention is a set of methods ...

Question 14

Protocols to prevent hold-and-wait conditions typically also prevent starvation.

Accepted Answer

A) True 
 B)False

Question 15

Deadlocks can be prevented only if

Accepted Answer

A)   all four necessary conditions cannot hold.
B)   at least one of the four necessary conditions cannot hold.
C)   mutual exclusion condition cannot hold.
D)   circular wait condition cannot hold.E) A) and B)
F) B) and C)

Question 16

Describe the four conditions that must hold simultaneously in a system if a deadlock is to occur.

Accepted Answer

For a set of processes to be deadlocked:...

Question 17

Describe a wait-for graph and how it detects deadlock.

Accepted Answer

If all resources have only a single inst...

Question 18

In a system that uses deadlock detection algorithm,

Accepted Answer

A)   a deadlock is detected as soon as it occurs.
B)   a deadlock is detected just before it occurs.
C)   a deadlock is detected sometime after it has occurred but not necessarily immediately.
D)   a deadlock is detected sometime before it occurs, but not necessarily just before.E) B) and C)
F) A) and D)

Question 19

What is one way to ensure that a circular-wait condition does not occur?

Accepted Answer

One way to ensure that this condition never holds is to impose a total ordering of all resource types, and to require that each process requests resources in an increasing order of enumeration. This can be accomplished by assigning each resource type a unique integer number to determine whether one precedes another in the ordering.

Question 20

Explain what has to happen for a set of processes to achieve a deadlocked state.

Accepted Answer

For a set of processes to exist in a dea...

Exam 8: Deadlocks

Describe how a safe state ensures deadlock will be avoided.

Correct Answer
verified
A safe state ensures that there is a seq...
View Answer

Deadlock prevention using preempting allocated resources cannot be used for

Correct Answer
verified

What does a claim edge signify in a resource-allocation graph?

Correct Answer
verified
A claim edge indicates that a process may request a resource at some time in the future. This edge resembles a request edge in direction, but is represented in the graph by a dashed line.

Recovery from a deadlock works best when a single process can be identified whose termination will break the circular wait.

Correct Answer
verified

The Linux Lockdep tool is

Correct Answer
verified
A

One necessary condition for deadlock is ______, which states that a resource can be released only voluntarily by the process holding the resource.

Correct Answer
verified

Describe two protocols to ensure that the hold-and-wait condition never occurs in a system.

Correct Answer
verified
One protocol requires each process to re...
View Answer

Ordering resources and requiring the resources to be acquired in order prevents the circular wait from occurring and therefore prevents deadlock from occurring.

Correct Answer
verified

Correct Answer
verified

A _____ could be preempted from a process.

Correct Answer
verified

If the sum of all needs for a resource type exceeds the available number of instances of that resource type, the system state is unsafe.

Correct Answer
verified

In a resource allocation graph, when a process releases a resource,

Correct Answer
verified

What is the difference between deadlock prevention and deadlock avoidance?

Correct Answer
verified
Deadlock prevention is a set of methods ...
View Answer

Protocols to prevent hold-and-wait conditions typically also prevent starvation.

Correct Answer
verified

Deadlocks can be prevented only if

Correct Answer
verified

Describe the four conditions that must hold simultaneously in a system if a deadlock is to occur.

Correct Answer
verified
For a set of processes to be deadlocked:...
View Answer

Describe a wait-for graph and how it detects deadlock.

Correct Answer
verified
If all resources have only a single inst...
View Answer

In a system that uses deadlock detection algorithm,

Correct Answer
verified

What is one way to ensure that a circular-wait condition does not occur?

Explain what has to happen for a set of processes to achieve a deadlocked state.

Correct Answer
verified
For a set of processes to exist in a dea...
View Answer

Exam 8: Deadlocks

Describe how a safe state ensures deadlock will be avoided.

Correct AnswerverifiedA safe state ensures that there is a seq...View AnswerShow Answer

Deadlock prevention using preempting allocated resources cannot be used for

Correct AnswerverifiedShow Answer

What does a claim edge signify in a resource-allocation graph?

Correct AnswerverifiedA claim edge indicates that a process may request a resource at some time in the future. This edge resembles a request edge in direction, but is represented in the graph by a dashed line.

Recovery from a deadlock works best when a single process can be identified whose termination will break the circular wait.

Correct AnswerverifiedShow Answer

The Linux Lockdep tool is

Correct AnswerverifiedA

One necessary condition for deadlock is ______, which states that a resource can be released only voluntarily by the process holding the resource.

Correct AnswerverifiedShow Answer

Describe two protocols to ensure that the hold-and-wait condition never occurs in a system.

Correct AnswerverifiedOne protocol requires each process to re...View AnswerShow Answer

Ordering resources and requiring the resources to be acquired in order prevents the circular wait from occurring and therefore prevents deadlock from occurring.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

A _____ could be preempted from a process.

Correct AnswerverifiedShow Answer

If the sum of all needs for a resource type exceeds the available number of instances of that resource type, the system state is unsafe.

Correct AnswerverifiedShow Answer

In a resource allocation graph, when a process releases a resource,

Correct AnswerverifiedShow Answer

What is the difference between deadlock prevention and deadlock avoidance?

Correct AnswerverifiedDeadlock prevention is a set of methods ...View AnswerShow Answer

Protocols to prevent hold-and-wait conditions typically also prevent starvation.

Correct AnswerverifiedShow Answer

Deadlocks can be prevented only if

Correct AnswerverifiedShow Answer

Describe the four conditions that must hold simultaneously in a system if a deadlock is to occur.

Correct AnswerverifiedFor a set of processes to be deadlocked:...View AnswerShow Answer

Describe a wait-for graph and how it detects deadlock.

Correct AnswerverifiedIf all resources have only a single inst...View AnswerShow Answer

In a system that uses deadlock detection algorithm,

Correct AnswerverifiedShow Answer

What is one way to ensure that a circular-wait condition does not occur?

Explain what has to happen for a set of processes to achieve a deadlocked state.

Correct AnswerverifiedFor a set of processes to exist in a dea...View AnswerShow Answer

Correct Answer
verified
A safe state ensures that there is a seq...
View Answer

Correct Answer
verified

Correct Answer
verified
A claim edge indicates that a process may request a resource at some time in the future. This edge resembles a request edge in direction, but is represented in the graph by a dashed line.

Correct Answer
verified

Correct Answer
verified
A

Correct Answer
verified

Correct Answer
verified
One protocol requires each process to re...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
Deadlock prevention is a set of methods ...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
For a set of processes to be deadlocked:...
View Answer

Correct Answer
verified
If all resources have only a single inst...
View Answer

Correct Answer
verified

Correct Answer
verified
For a set of processes to exist in a dea...
View Answer