made easy test series

Question

which of the require the executing code to be in kernel mode.

A)Performing a semaphore 'P' operation.

B)Making a system call

C)Disabling interrupt.

D)Both b and c

Comments

D) both b and c

http://www.jamesmolloy.co.uk/tutorial_html/10.-User%20Mode.html

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i think all require the kernel mode..@Magma can you please explain how B is correct only ..???

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SHUBHAM SHASTRI 

yes Ist I made mistake ..then within a minute I updated my answer ...... I think  'Making a system call ' and 'Disabling interrupt.' is the correct option (D).

 

 

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thnx

Answer 1

Answer is C - disabling interrupts. 

option A is definitely not the answer. 

option B - system calls can be made in the user mode which transfers the control to the kernel mode thereafter.

option C - disabling and enabling interrupts are handled by kernel