GATE 2005

Question 20

Normally user programs are prevented from handling I/O directly by I/O instructions in them. For CPUs having explicit I/O instructions, such I/O protection is ensured by having the I/O instructions privileged. In a CPU with memory mapped I/O, there is no explicit I/O instruction. Which one of the following is true for a CPU with memory mapped I/O?

A	I/O protection is ensured by operating system routine(s)
B	I/O protection is ensured by a hardware trap
C	I/O protection is ensured during system configuration
D	I/O protection is not possible

Operating-SystemsI/O-Handling

Question 20 Explanation:

I/O protection can be ensured by operating system. Because all the user application are not modified by user mode. Those are sent to kernel mode as a system calls.

Correct Answer: A

Question 20 Explanation:

I/O protection can be ensured by operating system. Because all the user application are not modified by user mode. Those are sent to kernel mode as a system calls.

Sohail Kumar

0 0 votes

Article Rating

0 Comments

Inline Feedbacks

View all comments