Three concurrent processes X, Y, and Z execute three different code segments that access and update certain shared variables. Process X executes the P operation (i.e., wait) on semaphores a, b and c; process Y executes the P operation on semaphores b, c and d; process Z executes the P operation on semaphores c, d, and a before entering the respective code segments. After completing the execution of its code segment, each process invokes the V operation (i.e., signal) on its three semaphores. All semaphores are binary semaphores initialized to one. Which one of the following represents a deadlock-free order of invoking the P operations by the processes?

5.6.3 Deadlocks and StarvationThe implementation of a semaphore with a waiting queue may result in asituation where two or more processes are waiting indefinitely for an eventthat can be caused only by one of the waiting processes. The event in questionis the execution of a signal() operation. When such a state is reached, theseprocesses are said to be deadlocked.To illustrate this, consider a system consisting of two processes, P0 and P1 ,each accessing two semaphores, S and Q , set to the value 1:P0 P1wait(S); wait(Q);wait(Q); wait(S);. .. .. .signal(S); signal(Q);signal(Q); signal(S);Suppose that P0 executes wait(S) and then P1 executes wait(Q) . When P0executes wait(Q) , it must wait until P1 executes signal(Q) . Similarly, whenP1 executes wait(S) , it must wait until P0 executes signal(S) . Since thesesignal() operations cannot be executed, P0 and P1 are deadlocked.We say that a set of processes is in a deadlocked state when every processin the set is waiting for an event that can be caused only by another processin the set. The events with which we are mainly concerned here are resourceacquisition and release. Other types of events may result in deadlocks, as weshow in Chapter 7. In that chapter, we describe various mechanisms for dealingwith the deadlock problem.Another problem related to deadlocks is indefinite blocking or starvation,a situation in which processes wait indefinitely within the semaphore. Indefi-nite blocking may occur if we remove processes from the list associated with asemaphore in LIFO (last-in, first-out) order.

When several processes access the same data concurrently and the outcome of the execution depends on the particular order in which the access takes place is called ________a.Dynamic conditionb.Essential conditionc.Critical conditiond.Race condition

In a multiprogramming system multiple processes exist concurrently in main memory.Select one:TrueFalse

Execution of one process does not affects the execution of other processes.Independent processDependent processCooperating processRace condition

Operations on processes