Operating Systems: Memory Management

Questions and Answers

What is the first action the operating system takes when a page fault occurs?

Resume the process immediately

Initiate disc IO immediately

Find a free page frame (correct)

Update the page table

What does the operating system do after allocating a free page frame?

Updates all page tables of running processes

Locks the memory to prevent further page faults

Immediately resumes the process that incurred the fault

Initiates disc IO to move the page from virtual memory (correct)

What action does the operating system take upon completion of the disc IO?

It runs a diagnostic check

It updates the page table (correct)

It forces a garbage collection

It powers off the system

What is one reason the operating system overcommits its available physical memory?

In anticipation that not all pages will be needed simultaneously Signup and view all the answers

When does the operating system run a page replacement algorithm?

To free up page frames periodically Signup and view all the answers

What happens to the process that incurred a page fault after the page table is updated?

It can resume execution from where it left off Signup and view all the answers

What is a potential analogy used to describe operating system's memory management strategy?

An airline overbooking its seats Signup and view all the answers

What occurs after the page has been retrieved from storage into the allocated page frame?

The operating system updates the corresponding page table Signup and view all the answers

What is a limitation of operating systems regarding page replacement algorithms?

The operating system's chosen algorithm may not suit all applications. Signup and view all the answers

What can enhance the efficiency of page replacement in operating systems?

Customization based on the application's memory access pattern. Signup and view all the answers

In addition to page replacement, what other aspect of the operating system can be customized?

The way processes are scheduled on the processor. Signup and view all the answers

Why might an operating system's default algorithm for page replacement not always be effective?

It does not adapt to individual memory access patterns. Signup and view all the answers

What factor influences how an operating system can customize page replacement algorithms?

The nature of the application's memory access. Signup and view all the answers

Study Notes

Memory Management and Page Faults

Page faults occur when a thread requires a page that is not currently in physical memory.
The operating system's first action upon a page fault is to locate a free page frame for the missing page.
After allocating a free page frame, the system initiates disk I/O to transfer the missing page from virtual memory to the newly identified page frame.
Upon completion of the I/O operation, the page is loaded into the allocated frame, and the page table for the respective thread is updated to map the virtual page to the physical frame.
Once the page table is updated, the thread can resume execution from the point of the page fault.

Page Replacement Algorithm

Operating systems often run page replacement algorithms to manage memory by freeing up page frames.
This proactive management helps prepare for future page faults by ensuring available frames can be allocated when needed.
Systems may overcommit physical memory, similar to airlines overbooking seats, operating under the assumption that not all pages will be required simultaneously.

Customization Opportunities

The operating system lacks insight into the specific memory access patterns of applications, leading to potential inefficiencies in page replacement algorithms.
Customization of page replacement strategies can be beneficial, particularly for applications with known access patterns, enhancing overall system performance.
Similar customization options are available for process scheduling and the handling of external events like interrupts in the operating system.

Description

This quiz delves into the intricacies of memory management within operating systems, focusing specifically on how page faults are handled. Participants will explore the steps that the operating system takes to manage memory efficiently and address situations where a page fault occurs.