Deck 7: Operating System Scheduling and Deadlock Prevention: a Comprehensive Guide

Question 1

Deadlock can occur ________.

A) only between two or more threads
B) only on multiprogrammed systems
C) only if resource sharing is allowed
D) none of the above

Answer 1

D

Question 2

Which of the following is not a major area of deadlock research?

A) prevention
B) avoidance
C) recovery
D) none of the above

Answer 2

D

Question 3

If a process is given the task of waiting for an event to occur, and if the system includes no provision for signaling that event, then we have ________.

A) one-process deadlock
B) starvation
C) mutual exclusion
D) circular wait

Answer 3

A

Question 4

Most deadlocks in operating systems develop because of the normal contention for _________ .

A) dedicated resources
B) processors
C) main memory
D) device drivers

Question 5

________ is characteristic of deadlocked systems.

A) Starvation
B) Circular waiting
C) Saturation
D) Aging

Question 6

To avoid deadlock in spooling systems, a system can ________.

A) provide considerably more space for spooling files than is likely to be needed
B) restrain the input spoolers so that they do not accept additional print jobs when the spooling files approach some saturation threshold
C) allow printing to begin before the job is completed so that a full, or nearly full, spooling file can begin emptying while a job is still executing
D) all of the above

Question 7

The solution to the Dining Philosophers problem must ________.

A) prevent deadlock
B) prevent starvation
C) ensure mutual exclusion
D) all of the above

Question 8

________ is a technique that prevents indefinite postponement.

A) Monitors
B) Mutual exclusion
C) Aging
D) Preemption

Question 9

Code that may be changed but is reinitialized each time it is used is said to be ________ .

A) serially reusable
B) reentrant
C) static
D) shared

Question 10

________ code is not modified as it executes and may be shared by several processes simultaneously.

A) Preemptible
B) Dynamic
C) Reentrant
D) Serially reusable

Question 11

________ resources are the kinds that tend to become involved in deadlocks.

A) Preemptible
B) Serially reusable
C) Reentrant
D) all of the above

Question 12

Which of the following is not a condition necessary for deadlock to exist?

A) wait-for condition
B) mutual-exclusion condition
C) circular-wait condition
D) indefinite-postponement condition

Question 13

_______ conditions a system to remove any possibility of deadlocks occurring.

A) Deadlock avoidance
B) Deadlock prevention
C) Deadlock detection
D) Deadlock recovery

Question 14

________ imposes less stringent conditions than deadlock prevention in an attempt to get better resource utilization while stopping deadlock from occurring.

A) Deadlock avoidance
B) Deadlock detection
C) Deadlock recovery
D) both a and c

Question 15

The strategy of denying the "wait-for" condition ________.

A) prevents deadlock from occurring
B) is commonly implemented
C) leads to poor resource utilization
D) both a and c

Question 16

The strategy of denying the "no-preemption" condition could lead to ________.

A) indefinite postponement
B) loss of work
C) poor resource utilization
D) both a and b

Question 17

The strategy of denying the "circular-wait" condition ________.

A) is a deadlock prevention technique that promotes portability
B) creates a linear ordering of resources
C) maximizes resource utilization
D) none of the above

Question 18

The system is said to be in an unsafe state if ________.

A) the operating system cannot guarantee that all current processes can complete their work within a finite time
B) the system is deadlocked
C) a thread is indefinitely postponed
D) mutual exclusion has been violated

Question 19

Dijkstra's Banker's Algorithm requires the system to maintain ________ for each process.

A) a count of the system's total resources
B) the maximum resources that can be requested
C) the current loan
D) both b and c

Question 20

Consider the following system state:
The system will be in a safe state if ________.

A) process P₁ is allocated one additional resource
B) process P₂ is allocated two additional resources
C) process P₃ is allocated three additional resources
D) process P₂ is allocated one additional resource

Question 21

An unsafe state implies ________.

A) the existence of deadlock
B) that deadlock will eventually occur
C) that some unfortunate sequence of events might lead to a deadlock
D) none of the above

Question 22

Consider the following system state:
The system will enter an unsafe state if ________.

A) process P₁ is allocated one additional resource
B) process P₂ is allocated two additional resources
C) process P₃ is allocated three additional resources
D) process P₂ is allocated one additional resource

Question 23

In the Banker's Algorithm, resource requests that would result in ________ are repeatedly denied until they can eventually be satisfied.

A) indefinite postponement
B) holding resources while waiting for others
C) unsafe states
D) all of the above

Question 24

________ is a weakness of the Banker's Algorithm.

A) Allowing the population of processes to vary over time
B) Enabling processes to hold their resources indefinitely
C) Requiring that processes state their maximum needs in advance
D) Enabling the number of resources to fluctuate

Question 25

The Banker's Algorithm ________.

A) can provide better resource utilization than deadlock prevention
B) incurs little overhead
C) is appropriate for real-time systems
D) facilitates applications programming

Question 26

________ is the process of determining that a deadlock exists and identifying the processes and resources involved in the deadlock.

A) Deadlock avoidance
B) Deadlock detection
C) Deadlock recovery
D) Deadlock prevention

Question 27

In a resource-allocation graph, ________ represent processes and ________ represent resources.

A) circles, squares
B) arrows, circles
C) squares, circles
D) arrows, squares

Question 28

In a resource-allocation graph, an arrow points from a ________ to a ________ to indicate that the system has allocated a specific resource of a specific type to the process.

A) square, large circle
B) square, small circle
C) large circle, square
D) small circle, square

Question 29

If a graph can be reduced by all its processes, then ________.

A) there is no deadlock
B) indefinite postponement cannot occur
C) the system is in an unsafe state
D) none of the above

Question 30

To ensure that data in a database remains in a consistent state when deadlocked processes are terminated, database systems typically perform resource allocations using ________.

A) checkpoints
B) rollback
C) aging
D) transactions

Question 31

Which of the following complicates deadlock recovery?

A) It may not be clear that the system has become deadlocked.
B) Most systems do not provide the means to suspend a process indefinitely.
C) The deadlock could involve many processes.
D) all of the above

Question 32

Many of today's personal computer systems ignore deadlock because ________.

A) the processor time required to check for deadlocks can significantly reduce system performance
B) they do not perform many concurrent operations that could lead to deadlock
C) the number of resources that operating systems must manage is decreasing dramatically
D) all of the above

Question 33

Deadlock will continue to be an important area of research in current and future systems because ________.

A) large-scale systems are becoming more oriented toward asynchronous parallel operations
B) small, portable devices, for which users cannot rely on an administrator to detect and rid a system of deadlock, are becoming more prevalent
C) there is an increasing tendency of operating systems designers to view data as a resource that must be managed carefully
D) all of the above