Question 1

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 systems 
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 systems A

Question 2

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 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

Deadlock prevention using preempting allocated resources cannot be used for

Accepted Answer

A)  mutexes. 
B)  CPU registers. 
C)  database transactions. 
D)  memory. 
A)  mutexes. 
B)  CPU registers. 
C)  database transactions. 
D)  memory.

Question 5

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

Question 6

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 7

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

Accepted Answer

A) True 
 B)False

Question 8

Describe how a safe state ensures deadlock will be avoided.

Accepted Answer

A safe state ensures that there is a seq

Question 9

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. 
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.

Question 10

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 11

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. 
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.

Question 12

A _____ could be preempted from a process.

Accepted Answer

A)  mutex lock 
B)  CPU registers 
C)  semaphore 
D)  file lock 
A)  mutex lock 
B)  CPU registers 
C)  semaphore 
D)  file lock

Question 13

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 14

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 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. 
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.

Question 16

What is the difference between deadlock prevention and deadlock avoidance?

Accepted Answer

Deadlock prevention is a set of methods

Question 17

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

Question 18

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

Accepted Answer

If all resources have only a single inst

Question 19

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 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

The Linux Lockdep tool is

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

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

Deadlock prevention using preempting allocated resources cannot be used for

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

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

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

Describe how a safe state ensures deadlock will be avoided.

In a system that uses deadlock detection algorithm,

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.

A _____ could be preempted from a process.

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

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

Deadlocks can be prevented only if

What is the difference between deadlock prevention and deadlock avoidance?

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

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

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

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

Introduction

Operating-System Structures

Processes

Threads Concurrency

Cpu Scheduling

Synchronization Tools

Synchronization Examples

Main Memory

Virtual Memory

Mass-Storage Structure

Io Systems

File-System Interface

File-System Implementation

File-System Internals

Security

Protection

Filters

Exam 8: Deadlocks

The Linux Lockdep tool is

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

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

Deadlock prevention using preempting allocated resources cannot be used for

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

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

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

Describe how a safe state ensures deadlock will be avoided.

In a system that uses deadlock detection algorithm,

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.

A _____ could be preempted from a process.

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

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

Deadlocks can be prevented only if

What is the difference between deadlock prevention and deadlock avoidance?

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

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

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

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

Introduction

Operating-System Structures

Processes

Threads Concurrency

Cpu Scheduling

Synchronization Tools

Synchronization Examples

Main Memory

Virtual Memory

Mass-Storage Structure

Io Systems

File-System Interface

File-System Implementation

File-System Internals

Security

Protection

Filters