GATE PYQ

Operating System

Q171.
Consider three concurrent processes P1, P2 and P3 as shown below, which access a shared variable D that has been initialized to 100. The process are executed on a uniprocessor system running a time-shared operating system. If the minimum and maximum possible values of D after the three processes have completed execution are X and Y respectively, then the value of Y-X is __________.

Q172.
Which of the following does not interrupt a running process ?

Q173.
At a particular time the value of counting semaphore is 10. It will become 7 after:

Q174.
Consider a non-negative counting semaphore S. The operation P(S) decrements S, and V(S) increments S. During an execution, 20 P(S) operations and 12V(S) operations are issued in some order. The largest initial value of S for which at least one P(S) operation will remain blocked is ________.

Q175.
At a particular time of computation the value of a counting semaphore is 7. Then 20 P operations and x V operations were completed on this semaphore. If the new value of semaphore is 5, x will be

Q176.
The process state transition diagram in the below figure is representative of

Q177.
Choose the correct alternatives (more than one may be correct) and write the corresponding letters only:At a particular time of computation, the value of a counting semaphore is 7. Then 20 P operations and 15 V operations were completed on this semaphore. The resulting value of the semaphore is :

Q178.
Dispatch latency is defined as

Q179.
Which is the correct definition of a valid process transition in an operating system?

Q180.
Consider the following threads, T_1, T_2, \text{ and }T_3 executing on a single processor, synchronized using three binary semaphore variables, S_1, S_2, \text{ and }S_3, operated upon using standard wait() and signal(). The threads can be context switched in any order and at any time.Which initialization of the semaphores would print the sequence BCABCABCA ...?