Question 1

Atomicity guarantees isolation from concurrent processes.

Accepted Answer

Atomicity ensures that a transaction is treated as a single, indivisible unit of work, which makes it isolated from concurrent processes. This means that either the transaction is completed successfully, or it is rolled back to its original state if it fails or is terminated in the middle.

Question 2

It is possible for one process to lock the mutex and for another process to unlock it.

Accepted Answer

A mutex (mutual exclusion) lock is designed to be locked and unlocked by the same thread or process. If one process locks a mutex, only that process is supposed to unlock it, ensuring that the critical section of code is safely executed without interference from other processes.

Question 3

Two or more processes can cooperate by means of simple signals, such that a process can be forced to stop at a specified place until it has received a specific signal.

Accepted Answer

This statement is true. Processes can communicate and cooperate with each other using signals to coordinate their activities, ensuring proper synchronization and avoiding conflicts. A process can be made to wait until it has received a specific signal before continuing its execution or performing a particular action, allowing it to coordinate its activities with other processes in the system. Signals can be used to communicate between processes or between a process and the operating system, enabling interprocess communication and coordination.

Question 4

When processes cooperate by communication, the various processes participate in a common effort that links all of the processes.

Accepted Answer

When processes communicate, they exchange information to carry out a common task or goal, and this creates a sense of cooperation and collaboration among the processes.

Question 5

Race condition is a situation in which two or more processes continuously change their states in response to changes in the other process(es) without doing any useful work.

Accepted Answer

A race condition occurs when two or more processes or threads access a shared resource or piece of data and try to modify it at the same time. This can lead to unpredictable behavior and errors, but it is not true that they are continuously changing their states without doing any useful work. In fact, the processes may be doing useful work, but the race condition makes it difficult to ensure consistency and correctness of the results.

Question 6

A semaphore that does not specify the order in which processes are removed from the queue is a _________ semaphore.
A) weak
B) general
C) strong
D) binary

Accepted Answer

A weak semaphore does not guarantee the order in which processes will be removed from the queue, allowing for potential variability in process execution order.

Question 7

The management of multiple processes within a uniprocessor system is __________ .
A) multiprogramming
B) structured applications
C) distributed processing
D) multiprocessing

Accepted Answer

Multiprogramming refers to the management of multiple processes within a uniprocessor system where the CPU switches rapidly between multiple processes to give the appearance of concurrent execution. Structured applications are a design methodology for developing software and are not related to managing multiple processes on a uniprocessor. Distributed processing refers to the coordination of multiple processors in a network to perform a task. Multiprocessing refers to the use of multiple processors in a system to execute tasks in parallel. Therefore, A is the best choice for this question.

Question 8

The case of cooperation by sharing covers processes that interact with other processes without being explicitly aware of them.

Accepted Answer

Sharing involves a passive form of cooperation, where processes interact with each other without needing to explicitly know about one another. This is in contrast to explicit cooperation or coordination, where processes actively communicate and coordinate their actions.

Question 9

Processes need to be synchronized to enforce mutual exclusion.

Accepted Answer

Processes may access shared resources simultaneously without any synchronization mechanism which leads to race conditions and inconsistent results. By enforcing mutual exclusion, only one process at a time can access the shared resource, avoiding conflicts and ensuring consistency.

Question 10

As an extension of the principles of modular design and structured programming, some applications can be effectively programmed as a set of concurrent processes.

Accepted Answer

Concurrent programming involves dividing a program into multiple concurrent processes that can run independently of each other. This approach can improve application performance and responsiveness, and is an extension of the principles of modular design and structured programming.

Question 11

The central themes of operating system design are all concerned with the management of processes and threads.

Accepted Answer

The management of processes and threads is indeed one of the central themes of operating system design. Other important themes include memory management, file and I/O management, and security.

Question 12

A situation in which a runnable process is overlooked indefinitely by the scheduler, although it is able to proceed, is __________ .
A) mutual exclusion
B) deadlock
C) starvation
D) livelock

Accepted Answer

This situation is called starvation, where a runnable process is not given access to the necessary resources, including the CPU, to proceed while other processes are hogging resources. This can happen when the scheduler gives priority to certain processes or when a process requires a particular resource that is being used by another process. Mutual exclusion refers to a situation where only one process can access a shared resource at a time, deadlock occurs when two or more processes are waiting for each other to release their resources, and livelock is a situation where processes are stuck in a loop trying to acquire the same resource.

Question 13

It is possible in a single-processor system to not only interleave the execution of multiple processes but also to overlap them.

Accepted Answer

In a single-processor system, processes can be interleaved (time-shared) but not overlapped, as only one process can execute at any given time.

Question 14

One of the most common problems faced in concurrent processing is the producer/consumer problem.

Accepted Answer

The producer/consumer problem is a well-known problem in the field of concurrent processing where one or more producers create data items and store them in a buffer, and one or more consumers retrieve data items from the buffer for processing. It is one of the most common problems of concurrent processing.

Question 15

A process that is waiting for access to a critical section does not consume processor time.

Accepted Answer

The answer of A process that is waiting for access...

Question 16

The functioning of a process, and the output it produces, must be independent of the speed at which its execution is carried out relative to the speed of other concurrent processes.

Accepted Answer

This statement describes the property of concurrency known as "independence of execution speed". It means that a process should produce the same output regardless of whether it is executed quickly or slowly, and regardless of whether it is executed in parallel with other processes or not. This is an important property for ensuring that concurrent systems behave correctly and predictably.

Question 17

Concurrent processes do not come into conflict with each other when they are competing for the use of the same resource.

Accepted Answer

Concurrent processes can come into conflict with each other when they are competing for the use of the same resource. This can lead to race conditions, deadlocks, and other synchronization issues. Therefore, it is important to use appropriate synchronization mechanisms to ensure that multiple processes can access shared resources in a coordinated and safe manner.

Question 18

The requirement that when one process is in a critical section that accesses shared resources, no other process may be in a critical section that accesses any of those shared resources is _________ .
A) critical section
B) livelock
C) mutual exclusion
D) atomic operation

Accepted Answer

The requirement described in the question is mutual exclusion, which means that only one process at a time can access the shared resources to avoid conflicting updates or inconsistencies. The other options are not relevant to the given requirement.

Question 19

A means for two processes to exchange information is with the use of ___________ .
A) spinlocks
B) event flags
C) condition variables
D) messages

Accepted Answer

Messages are a common and flexible means for two processes to exchange information. They allow sending and receiving of complex data structures, support different communication patterns (e.g. one-to-one, one-to-many, many-to-one), and can be implemented using different mechanisms (e.g. sockets, pipes, message queues). Spinlocks, event flags, and condition variables are synchronization mechanisms that ensure mutually exclusive or orderly access to shared resources, but they do not provide a direct way to exchange information between processes.

Question 20

The sharing of main memory among processes is useful to permit efficient and close interaction among processes because such sharing does not lead to any problems.

Accepted Answer

Sharing of main memory among processes can lead to problems such as race conditions, deadlock, and incorrect data synchronization. Therefore, appropriate synchronization mechanisms should be used to ensure safe and efficient memory sharing among processes.

Quiz 5: Concurrency: Mutual Exclusion and Synchronization