What is a semaphore?

• A. Is a binary mutex
• B. Must be accessed from only one process
• C. Can be accessed from multiple processes
• D. None of the mentioned

What are the two kinds of semaphores?

• A. Mutex & counting
• B. Binary & counting
• C. Counting & decimal
• D. Decimal & binary

What is a mutex?

• A. Is a binary mutex
• B. Must be accessed from only one process
• C. Can be accessed from multiple processes
• D. None of the mentioned

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? (GATE 1987)

• A. 42
• B. 2
• C. 7
• D. 12

A binary semaphore is a semaphore with integer values ____________

• A. 1
• B. -1
• C. 0.8
• D. 0.5

The following pair of processes share a common variable X. Process A int Y; A1: Y = X*2; A2: X = Y; Process B int Z; B1: Z = X+1; B2: X = Z; X is set to 5 before either process begins execution. As usual, statements within a process are executed sequentially, but statements in process A may execute in any order with respect to statements in process B. How many different values of X are possible after both processes finish executing?

• A. Two
• B. Three
• C. Four
• D. Eight

The program follows to use a shared binary semaphore T. Process A int Y; A1: Y = X*2; A2: X = Y; signal(T); Process B int Z; B1: wait(T); B2: Z = X+1; X = Z; T is set to 0 before either process begins execution and, as before, X is set to 5. Now, how many different values of X are possible after both processes finish executing?

• A. One
• B. Two
• C. Three
• D. Four

Semaphores are mostly used to implement ____________

• A. System calls
• B. Ipc mechanisms
• C. System protection
• D. None of the mentioned

Spinlocks are intended to provide __________ only.

• A. Mutual exclusion
• B. Bounded waiting
• C. Aging
• D. Progress

In classless addressing, there are no classes but addresses are still granted in ______

• A. Ips
• B. Blocks
• C. Codes
• D. Sizes