OS Kernel

Question

 

Please explain each point.
My assumptions are;
1.kernel must save the register values.It should be FALSE as it can be the case if the process is terminated.Thus, no need to save. 

2.kernel must close the files. Explain this point in both the cases(the process is terminated or the time slice of the process is expired)

3.kernel must restore the register values. It should also be FALSE as the coming runnable process might be a new process that has not dealt with registers earlier.Thus, no need to restore. 

4.kernel must save the content of memory onto disk. Explain this too.

Comments

Can somebody explain the 4th point "kernel must save the content of memory onto disk" ??

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@srestha

ma'm

why this false "kernel must save the content of memory onto disk"

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@Gateasp2020

Chk again I have explained it already.

If u still getting doubt, tell me where r u getting wrong in my statement

Answer 1

On process switch, the PCB (Process Control Block) is used.

i. Of course true. The kernel will be saving the register values of the currently running process. Think about the Program Counter and other CPU registers.

ii. Not a must. I mean what might be going wrong? The PCB maintains the list of open files for the particular process.

iii. True. The execution needs to start again from the point it was stopped so the registers will be reloaded.

If a new process has come for execution: the program counter(set to 0), stack pointers may still be loaded.

iv. Not a must.

Ans: Option (C)

Comments

Thank you.

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But then options given in the question must be incorrect.

What should be the answer?

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Option C