1 The basic features of modern operating system are_________and sharing

A multiprogramming

B interrupt

C concurrency

D real-time processing

2.Among the following disk allocation policies, which one is best for random access and extending file easily _________.

A Sequential Allocation

B Indexed Allocation

C Linked-List Allocation

D Hashed Allocation

3.The resource that allows only one process to access exclusively for a while is called as ______.

A Shared resource

B critical region

C critical resource

D Shared region

4.Which event can lead to an external interrupt ______.

A.keyboard input

B.divided by 0

C.overflow in calculation

D.page fault

5.Hard disk can be classified as _________.

A block device

B character device

C network device

D exclusive device