操作系统选择题·五

1. Concurrent access to shared data may result in ____________

   A. data consistency

   B.data insecurity

   C.data inconsistency

   D.none of the mentioned

   
   答案：C

2. A situation where several processes access and manipulate the same data concurrently and the outcome of the execution depends on the particular order in which access takes place is called ____________

   A. data consistency

   B.race condition

   C.aging

   D.starvation

   
   答案：B

3. Which of the following conditions must be satisfied to solve the critical section problem?

   A. Mutual Exclusion

   B. Progress

   C. Bounded Waiting

   D. All of the mentioned

   
   答案：D

4. A minimum of _____ variable(s) is/are required to be shared between processes to solve the critical section problem.

   A. one

   B.two

   C.three

   D.four

   
   答案：B

5. An un-interruptible unit is known as ____________

   A. single

   B.atomic

   C.static

   D.none of the mentioned

   
   答案：B

6. Semaphore is a/an _______ to solve the critical section problem.

   A. hardware for a system

   B.special program for a system

   C.integer variable

   D.none of the mentioned

   
   答案：C

7. What is the main disadvantage of spinlocks?

   A. they are not sufficient for many process

   B. they require busy waiting

   C. they are unreliable sometimes

   D. they are too complex for programmers

   
   答案：B

8. If the semaphore value is negative ____________

   A. its magnitude is the number of processes waiting on that semaphore

   B.it is invalid

   C.no operation can be further performed on it until the signal operation is performed on it

   D.none of the mentioned

   
   答案：A

9. What are the two kinds of semaphores?

   A. mutex & counting

   B. binary & counting

   C. counting & decimal

   D. decimal & binary