Question 1

Which of the following system calls does not return control to the calling point, on termination?

Accepted Answer

The exec system call replaces the current process image with a new process image, thus it does not return to the calling point on termination. The other system calls mentioned (fork, ioctl, longjmp) do return control to the calling point after execution.

Question 2

Which of the following system calls transforms executable binary file into a process?

Accepted Answer

The exec family of functions replaces the current process image with a new process image specified by an executable binary file, effectively transforming the executable file into a running process.

Question 3

Which of the following calls never returns an error?

Accepted Answer

`getpid()` is a system call that returns the process ID of the calling process. It does not fail under normal circumstances, as the process ID is always available to a running process.

Question 4

A fork system call will fail if

Accepted Answer

A fork system call will fail if the system's limit on the maximum number of processes is reached. This is because the system can only handle a certain number of processes at a time, and attempting to exceed this limit would not be possible, leading to the failure of the fork call. The other options do not directly cause a fork to fail.

Question 5

If a thread invokes the exec system call

Accepted Answer

The exec system call replaces the current process image with a new process image specified by the program. This means the entire process, including all threads, is replaced by the program specified in the exec call.

Question 6

If exec is called immediately after forking

Accepted Answer

When exec is called immediately after forking, the program specified in the parameter to exec replaces the entire process, including its address space, memory, and execution stack. This means the original process is completely replaced by the new program.

Question 7

If a process does not call exec after forking

Accepted Answer

When a process forks, all threads in the parent process are duplicated in the child process. If exec is not called, the child process continues to run the same program as the parent, with all threads duplicated.

Question 8

What is Thread cancellation?

Accepted Answer

Thread cancellation is the process of terminating a thread before it has completed its execution or before it has naturally finished its work.

Question 9

When a web page is loading, and the user presses a button on the browser to stop loading the page?

Accepted Answer

When a user presses a button on the browser to stop loading a web page, the thread or process responsible for loading the page is cancelled. This action halts the loading process, preventing any further data from being fetched or displayed from that particular request.

Question 10

When one thread immediately terminates the target thread, it is called___________

Accepted Answer

Asynchronous cancellation occurs when one thread immediately terminates the target thread, without waiting for the target thread to reach a certain point or complete its current task.

Question 11

When the target thread periodically checks if it should terminate and terminates itself in an orderly manner, it is called?

Accepted Answer

Deferred cancellation occurs when a thread periodically checks if it should terminate, allowing it to end its operations safely and orderly.

Question 12

Cancelling a thread asynchronously

Accepted Answer

Cancelling a thread asynchronously may not free each resource because it can be terminated at any point without completing its cleanup code, potentially leaving allocated resources unreleased.

Question 13

Cancellation point is the point where

Accepted Answer

Cancellation points are specific points in a thread where it is safe to cancel the thread, ensuring that resources are properly cleaned up and the system remains in a consistent state.

Question 14

If multiple threads are concurrently searching through a database and one thread returns the result then the remaining threads must be___________

Accepted Answer

When one thread finds the result in a concurrent search scenario, the remaining threads should ideally be cancelled to save resources and improve efficiency, as their continued execution would be unnecessary.

Question 15

Signals that occur at the same time, are presented to the process___________

Accepted Answer

Signals that occur simultaneously are presented to the process one at a time, but the order in which they are presented does not follow any specific sequence. This is due to the nature of how operating systems handle signal delivery, where multiple signals can be pending, but their handling is serialized.

Question 16

Which of the following is not TRUE?

Accepted Answer

Signals in operating systems are typically managed through more complex mechanisms than simply updating a field in a signal table. The handling of signals involves checking the process's signal mask, determining the appropriate action (default action, ignore, or catch through a signal handler), and possibly delivering the signal. The statement that each signal is maintained by a single bit is a simplification but essentially correct in the context of how signals are represented in terms of pending and blocked states.

Question 17

Signals of a given type___________

Accepted Answer

The answer of Signals of a given type___________
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Question 18

The three ways in which a process responds to a signal are___________

Accepted Answer

A process can respond to a signal by ignoring it, handling it through a signal handler, or performing some default action predefined by the system for that particular signal.

Question 19

Signals are identified by___________

Accepted Answer

Signals are identified by signal identifiers, which are typically defined as macros in the signal.h header file in C and C++ programming languages. These identifiers allow the program to refer to signals by name rather than by their numeric values.

Question 20

When a process blocks the receipt of certain signals?

Accepted Answer

The answer of When a process blocks the receipt of...

Quiz 23: Operating System Concepts: System Calls, Threads, and Signals