Operating Systems Exam 2 Exam
QUESTIONS AND CORRECT ANSWERS
Assume count is a variable name, which of the following operations is atomic? - CORRECT
ANSWER D. none of the above
Which of the following is true for race condition? - CORRECT ANSWER - Race condition
occurs where several processes access and manipulate the same data concurrently
- When race condition occurs, the outcome of the execution depends on the particular order in which
the access takes place
Which of the following actions should be performed among cooperating processes? - CORRECT
ANSWER C) both of the above
In _________, the process may be changing common variables, updating a table, writing a file, and so
on. - CORRECT ANSWER Critical section
In _________, the process requests permission to access and modify variables shared with others. -
CORRECT ANSWER Entry Section
Which of the following critical-section problem's requirements ensures only one process is active in
its critical section at a time? - CORRECT ANSWER mutual exclusion
Which of the following critical-section problem's requirements ensures programs will cooperatively
determine what process will next enter its critical section? - CORRECT ANSWER progress
Which of the following critical-section problem's requirements limits the amount of time a program
will wait before it can enter its critical section? - CORRECT ANSWER Progress
Which of the following is true regarding the requirements for the solutions to critical-section
problem? - CORRECT ANSWER bounded waiting implies progress
,Which of the following is true for the solutions to critical-section problems? - CORRECT ANSWER
Bounded waiting implies progress, and progress implies no deadlock
Which of the following is NOT true for Peterson's solution? - CORRECT ANSWER Peterson's
solution works for synchronization among more than two processes
Which of the following variables are shared between the processes in Peterson's solution? -
CORRECT ANSWER both of the above
Which of the following indicates that Pi can enter the critical section in Peterson's solution? -
CORRECT ANSWER flag[j] == false or turn == i
Which of the following is a software-based solution to the critical-section problem? - CORRECT
ANSWER Peterson's solution
Which of the following solutions needs hardware support for the critical section problem? -
CORRECT ANSWER All of the above
Which of the following is not true about test_and_set instruction? - CORRECT ANSWER
Returns the new value of passed parameter
Which of the following is not true about compare_and_swap instruction? - CORRECT ANSWER
It is executed atomicallyN) Returns the original value of passed parameter*D) Set the new
value of passed parameter to "TRUE"E) Set the variable "value" the value of the passed parameter
"new_value" but only if "value" =="expected"
Assume the binary variable lock is initialized to be 0, which of the following can be an
implementation of the entry section to solve the critical-section problem? - CORRECT ANSWER
both of statement 1 and 2
Which of the following regarding mutex lock is NOT true? - CORRECT ANSWER mutex lock
is a hardware solution to critical-section problem
When mutex lock is implemented as a binary semaphore, what should its value be initialized to be? -
CORRECT ANSWER 0
, The counting semaphore is initialized to ___________. - CORRECT ANSWER the number of
resources available
Which of the following is NOT true regarding semaphore implementation? - CORRECT ANSWER
A process that is suspended, waiting on the semaphore, should be restarted when some other
process executes a signal() operation.
What is the correct order of operations for protecting a critical section using a binary semaphore? -
CORRECT ANSWER wait() followed by signal()
Which of the following statements is true? - CORRECT ANSWER Spinlocks can be used to
prevent busy waiting in the implementation of semaphore.
Which of the following is NOT true? - CORRECT ANSWER Since semaphore and mutex lock
are tools for synchronization, process that have used semaphores or mutex locks should not cause
deadlocks
Which of the following is NOT true regarding conditional variable, e.g. x? - CORRECT ANSWER
x.wait()means that the process invoking this operation is suspended until another process
invokes x.signal()
Which of the following may cause a liveness failure? - CORRECT ANSWER all of the options
Which of the following is true? - CORRECT ANSWER Deadlock doesn't imply starvation;
Under which of the following contention loads does traditional synchronization become faster than
CAS-based synchronization? - CORRECT ANSWER high contention
Which of the following are efforts to towards developing scalable, efficient tools that address the
demands of concurrent programming? - CORRECT ANSWER all of the options
Race conditions can result in corrupted values of shared data. - CORRECT ANSWER
QUESTIONS AND CORRECT ANSWERS
Assume count is a variable name, which of the following operations is atomic? - CORRECT
ANSWER D. none of the above
Which of the following is true for race condition? - CORRECT ANSWER - Race condition
occurs where several processes access and manipulate the same data concurrently
- When race condition occurs, the outcome of the execution depends on the particular order in which
the access takes place
Which of the following actions should be performed among cooperating processes? - CORRECT
ANSWER C) both of the above
In _________, the process may be changing common variables, updating a table, writing a file, and so
on. - CORRECT ANSWER Critical section
In _________, the process requests permission to access and modify variables shared with others. -
CORRECT ANSWER Entry Section
Which of the following critical-section problem's requirements ensures only one process is active in
its critical section at a time? - CORRECT ANSWER mutual exclusion
Which of the following critical-section problem's requirements ensures programs will cooperatively
determine what process will next enter its critical section? - CORRECT ANSWER progress
Which of the following critical-section problem's requirements limits the amount of time a program
will wait before it can enter its critical section? - CORRECT ANSWER Progress
Which of the following is true regarding the requirements for the solutions to critical-section
problem? - CORRECT ANSWER bounded waiting implies progress
,Which of the following is true for the solutions to critical-section problems? - CORRECT ANSWER
Bounded waiting implies progress, and progress implies no deadlock
Which of the following is NOT true for Peterson's solution? - CORRECT ANSWER Peterson's
solution works for synchronization among more than two processes
Which of the following variables are shared between the processes in Peterson's solution? -
CORRECT ANSWER both of the above
Which of the following indicates that Pi can enter the critical section in Peterson's solution? -
CORRECT ANSWER flag[j] == false or turn == i
Which of the following is a software-based solution to the critical-section problem? - CORRECT
ANSWER Peterson's solution
Which of the following solutions needs hardware support for the critical section problem? -
CORRECT ANSWER All of the above
Which of the following is not true about test_and_set instruction? - CORRECT ANSWER
Returns the new value of passed parameter
Which of the following is not true about compare_and_swap instruction? - CORRECT ANSWER
It is executed atomicallyN) Returns the original value of passed parameter*D) Set the new
value of passed parameter to "TRUE"E) Set the variable "value" the value of the passed parameter
"new_value" but only if "value" =="expected"
Assume the binary variable lock is initialized to be 0, which of the following can be an
implementation of the entry section to solve the critical-section problem? - CORRECT ANSWER
both of statement 1 and 2
Which of the following regarding mutex lock is NOT true? - CORRECT ANSWER mutex lock
is a hardware solution to critical-section problem
When mutex lock is implemented as a binary semaphore, what should its value be initialized to be? -
CORRECT ANSWER 0
, The counting semaphore is initialized to ___________. - CORRECT ANSWER the number of
resources available
Which of the following is NOT true regarding semaphore implementation? - CORRECT ANSWER
A process that is suspended, waiting on the semaphore, should be restarted when some other
process executes a signal() operation.
What is the correct order of operations for protecting a critical section using a binary semaphore? -
CORRECT ANSWER wait() followed by signal()
Which of the following statements is true? - CORRECT ANSWER Spinlocks can be used to
prevent busy waiting in the implementation of semaphore.
Which of the following is NOT true? - CORRECT ANSWER Since semaphore and mutex lock
are tools for synchronization, process that have used semaphores or mutex locks should not cause
deadlocks
Which of the following is NOT true regarding conditional variable, e.g. x? - CORRECT ANSWER
x.wait()means that the process invoking this operation is suspended until another process
invokes x.signal()
Which of the following may cause a liveness failure? - CORRECT ANSWER all of the options
Which of the following is true? - CORRECT ANSWER Deadlock doesn't imply starvation;
Under which of the following contention loads does traditional synchronization become faster than
CAS-based synchronization? - CORRECT ANSWER high contention
Which of the following are efforts to towards developing scalable, efficient tools that address the
demands of concurrent programming? - CORRECT ANSWER all of the options
Race conditions can result in corrupted values of shared data. - CORRECT ANSWER
