GATE - 2005 | OS | Normally user programs are prevented from handling I/O directly by

GATE - 2005 | OS | Normally user programs are prevented from handling I/O directly by
Posted on 19-02-2022

GATE - 2005 [Operating System]

Question:

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

   

Solution:

Option (A) is Correct.

I/O protection can be ensured by operating system.

Because all the user application are not modified by user mode.

Those are sent to kernal mode as a system calls.

Thank You

Download App for Free PDF Download

GovtVacancy.Net Android App: Download

government vacancy govt job sarkari naukri android application google play store https://play.google.com/store/apps/details?id=xyz.appmaker.juptmh