Question 1

Which of the following is not a reason why the programming community is so intent on concurrent programming?
A) Concurrent programming enables us to express more natural solutions to problems that are inherently parallel.
B) The true hardware parallelism possible with multiprocessors and distributed systems can only be harnessed through concurrent programming.
C) Concurrent programs are easier to write, debug, modify and prove correct than sequential programs.
D) Systems such as air traffic control systems, mission-critical systems, and real-time process control systems can benefit from concurrent programming.

Accepted Answer

Concurrent programs are generally more complex to write, debug, modify, and prove correct than sequential programs, due to issues like race conditions and deadlocks.

Question 2

________ supports concurrent programming, in addition to many features needed to implement real concurrent systems.
A) Java
B) Visual Basic .NET
C) Python
D) all of the above

Accepted Answer

All the listed languages (Java, Visual Basic .NET, and Python) support concurrent programming through various constructs and libraries.

Question 3

________ is a software architectural technique that improves modularity and facilitates the development of more reliable software systems.
A) Mutual exclusion
B) Multithreading
C) Information hiding
D) Concurrent programming

Accepted Answer

Information hiding is a software architectural technique that improves modularity by encapsulating details and exposing only necessary parts of a module, which helps in developing more reliable software systems.

Question 4

To avoid indefinite postponement, a monitor ________.
A) terminates newly arriving threads when other threads are waiting
B) gives a higher priority to waiting threads than to newly arriving ones
C) terminates waiting threads when new threads arrive
D) gives a higher priority to newly arriving threads than to waiting ones

Accepted Answer

A monitor gives a higher priority to waiting threads than to newly arriving ones to ensure that waiting threads are eventually executed, thus avoiding indefinite postponement.

Question 5

Monitors implement ________ between threads of execution.
A) mutual exclusion
B) synchronization
C) both a and b
D) none of the above

Accepted Answer

Monitors are a synchronization construct that provide mutual exclusion and synchronization between threads of execution.

Question 6

A thread can exit a monitor by ________.
A) completing execution of the code protected by the monitor
B) sleeping inside the monitor
C) waiting on a condition variable
D) both a and c

Accepted Answer

A thread can exit a monitor by completing execution of the code protected by the monitor or by waiting on a condition variable.

Question 7

Monitor initialization ________.
A) occurs each time a thread returns a resource
B) typically sets a variable indicating that the monitor initially is in use
C) occurs only once, before threads begin using the monitor
D) occurs each time a thread requests access to a resource

Accepted Answer

Monitor initialization occurs only once, before threads begin using the monitor, to set up the necessary structures and variables for synchronization.

Question 8

Which of the following statements about using a circular buffer to implement print spooling is false?
A) The despooler thread tends to run at a slower speed than the spooler thread.
B) A circular buffer can "take up the slack" resulting from the mismatch in the speeds of the spooler and despooler threads.
C) If the system always generates print lines faster than the printer can print them, the buffer will always be full.
D) The spooler thread tends to run at a slower speed than the despooler thread.

Accepted Answer

The spooler thread typically runs faster than the despooler thread, as it is responsible for quickly adding data to the buffer, while the despooler thread processes and sends data to the printer, which can be slower.

Question 9

If the producer and consumer work at approximately the same speed, using the circular buffer can ________ the average speed of the application.
A) decrease
B) have no effect on
C) increase
D) none of the above

Accepted Answer

The circular buffer can increase the average speed of the application by allowing the producer to continue producing items even if the consumer is slow to consume them. This is because the circular buffer acts as a buffer between the producer and consumer, allowing the producer to store items that the consumer has not yet consumed.

Question 10

In the readers/writers problem, cascading in readers ________.
A) forces all arriving threads to wait
B) continues until all waiting readers have become active
C) allows waiting readers to become active as soon as another reader finishes
D) all of the above

Accepted Answer

Cascading in readers allows waiting readers to become active as soon as another reader finishes.

Question 11

________ is important for preventing indefinite postponement in the readers/writers problem.
A) Giving preference to waiting readers over waiting writers
B) Ensuring that no writer thread is waiting to write when a new reader begins reading
C) Forcing that arriving readers to wait while waiting readers are cascading
D) all of the above

Accepted Answer

All options are strategies to prevent indefinite postponement by balancing the access between readers and writers, ensuring fairness and avoiding starvation.

Question 12

Which type of monitor allows a thread inside the monitor to signal that the monitor will soon become available, but still maintain a lock on the monitor until it exits?
A) signal-and-exit
B) signal-and-wait
C) signal-and-continue
D) signal-and-wake

Accepted Answer

Signal-and-continue allows a thread to signal that the monitor will soon be available while still maintaining the lock until it exits.

Question 13

In Java, a(n)________ is a queue of threads awaiting entry into a monitor.
A) wait set (or queue)
B) entry set
C) notified set
D) either a or b

Accepted Answer

The answer of In Java, a(n)________ is a queue of...

Question 14

In Java, a(n)________ is a queue of threads waiting to reenter the monitor for an object.
A) wait set (or queue)
B) entry set (or queue)
C) notified set
D) either a or b

Accepted Answer

The answer of In Java, a(n)________ is a queue of...

Question 15

In Java, the ________ method wakes all threads in the entry and wait sets.
A) notify
B) signal
C) notifyAll
D) signalAll

Accepted Answer

The `notifyAll` method in Java is used to wake up all threads that are waiting on the object's monitor, which includes both the entry and wait sets.

Question 16

In the Java implementation of the producer/consumer relationship, the producer thread remains in the ________ until it is notified by another thread that it may proceed.
A) ready state
B) running state
C) waiting state
D) none of the above

Accepted Answer

In the producer/consumer relationship, the producer thread enters the waiting state when it has to wait for the consumer to consume data, typically when a shared resource like a buffer is full. It remains in this state until it is notified by another thread (usually the consumer) that it can proceed.

Question 17

Methods declared as ________ encapsulate critical sections of a program that can only be occupied by one thread at a time.
A) static
B) synchronized
C) private
D) protected

Accepted Answer

Methods declared as synchronized encapsulate critical sections of a program that can only be occupied by one thread at a time.

Question 18

The size of a circular buffer is important because ________.
A) if the number of buffer slots is too large, threads will wait more often
B) if the number of buffer slots is too small, there would be wasted memory
C) if the number of buffer slots is too small, threads will wait more often.
D) if the number of buffer slots is too large, fewer threads can access the buffer

Accepted Answer

If the number of buffer slots is too small, threads will wait more often because there may not be enough space to accommodate all the data being produced or consumed, leading to delays.

Question 19

Which variable(s) must be shared between threads to implement a producer/consumer relationship using a circular buffer?
A) variables that maintain read and write buffer locations
B) a variable that maintains a count of occupied buffers
C) a reference to a buffer object that holds data used by the readers/writers and provides access methods
D) all of the above

Accepted Answer

The answer of Which variable(s) must be shared between threads...

Quiz 6: Concurrency and Deadlock in Database Systems: Exploring Monitor Implementation and Thread Synchronization in Java

Which of the following is not a reason why the programming community is so intent on concurrent programming?

________ supports concurrent programming, in addition to many features needed to implement real concurrent systems.

________ is a software architectural technique that improves modularity and facilitates the development of more reliable software systems.

To avoid indefinite postponement, a monitor ________.

Monitors implement ________ between threads of execution.

A thread can exit a monitor by ________.

Monitor initialization ________.

Which of the following statements about using a circular buffer to implement print spooling is false?

If the producer and consumer work at approximately the same speed, using the circular buffer can ________ the average speed of the application.

In the readers/writers problem, cascading in readers ________.

________ is important for preventing indefinite postponement in the readers/writers problem.

Which type of monitor allows a thread inside the monitor to signal that the monitor will soon become available, but still maintain a lock on the monitor until it exits?

In Java, a(n) ________ is a queue of threads awaiting entry into a monitor.

In Java, a(n) ________ is a queue of threads waiting to reenter the monitor for an object.

In Java, the ________ method wakes all threads in the entry and wait sets.

In the Java implementation of the producer/consumer relationship, the producer thread remains in the ________ until it is notified by another thread that it may proceed.

Methods declared as ________ encapsulate critical sections of a program that can only be occupied by one thread at a time.

The size of a circular buffer is important because ________.

Which variable(s) must be shared between threads to implement a producer/consumer relationship using a circular buffer?