Page fault handling in Operating Systems - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a page fault in an operating system?

A page fault happens when a program tries to access a part of memory that is not currently in the physical RAM. The operating system then needs to bring the required data from disk to RAM.

beginner

What is the first step the OS takes when a page fault occurs?

The OS checks if the memory access is valid and if the page is actually on disk or if it is an invalid access causing an error.

beginner

Why does the OS bring a page from disk to RAM during page fault handling?

Because the program needs that page to continue running, and it must be in RAM for the CPU to access it quickly.

intermediate

What happens if the page fault is caused by an invalid memory access?

The OS usually terminates the program or raises an error because the program tried to access memory it shouldn't.

intermediate

How does the OS update the page table after handling a page fault?

The OS updates the page table to mark the page as present in RAM and sets the correct frame address so future accesses do not cause faults.

What triggers a page fault in an operating system?

A Network failure

B Accessing a page not in physical memory

C Running out of disk space

D CPU overheating

A page fault occurs when a program tries to access a page that is not currently loaded in RAM.

What does the OS do first when a page fault occurs?

A Clears the RAM

B Immediately terminates the program

C Checks if the access is valid

D Restarts the computer

The OS first checks if the memory access causing the fault is valid before taking further action.

Where does the OS load the missing page from during page fault handling?

A From disk storage

B From the CPU cache

C From the network

D From another program

The OS loads the missing page from disk storage into RAM.

What happens if the page fault is due to an invalid memory access?

A The OS increases RAM size

B The OS loads the page anyway

C The OS ignores the fault

D The OS raises an error or terminates the program

Invalid memory access causes the OS to raise an error or stop the program to prevent damage.

After handling a page fault, how does the OS prevent the same fault from happening again for that page?

A Updates the page table to mark the page as present

B Deletes the page from disk

C Disables paging

D Restarts the program

The OS updates the page table so the page is marked as present in RAM for future accesses.

Explain the steps the operating system takes when a page fault occurs.

Think about what the OS must do to get the needed data into RAM and continue the program.

Describe what happens if a program tries to access memory it is not allowed to during page fault handling.

Consider how the OS protects memory and handles errors.