Page Faults and Handling Techniques Quiz Quiz

Explore key concepts of page faults and memory management with fundamental questions about causes, handling techniques, and effects. Enhance your understanding of virtual memory, page replacement algorithms, and system performance in operating systems.

1. Definition of a Page Fault

   Which of the following best describes a page fault in a virtual memory system?

   1. An event when a required page is not found in physical memory
   2. A type of file system error due to a corrupt file
   3. A hardware failure in the memory module
   4. A situation where two processes use the same page simultaneously

   Explanation: A page fault occurs when a program requests a page not currently stored in physical memory, requiring the operating system to bring it in from secondary storage. Simultaneous use of a page is a concurrency issue, not a page fault. Hardware failures are unrelated to page faults. File system errors also do not involve pages as memory management units do.

2. Page Fault Handling Step

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

   1. Delete the process from memory
   2. Restart the process from the beginning
   3. Determine whether the memory reference is valid
   4. Immediately swap the page to disk

   Explanation: The operating system first checks if the page fault was caused by a valid memory reference before proceeding. It does not instantly swap pages or restart the process before determining validity. Deleting the process is not standard procedure for a page fault.

3. Reducing Page Faults

   Which approach can decrease the frequency of page faults in a system?

   1. Increasing the size of the physical memory (RAM)
   2. Reducing the number of processes
   3. Using a slower CPU
   4. Defragmenting the hard drive

   Explanation: Larger physical memory allows more pages to be kept in RAM, reducing page fault frequency. Reducing processes may help indirectly but is not a scalable solution. Defragmenting the hard drive optimizes disk access, not memory faults. A slower CPU does not affect the rate of page faults.

4. Page Replacement Algorithm Identification

   In which page replacement algorithm is the page that has not been used for the longest time replaced first?

   1. Optimal Replacement
   2. First-In, First-Out (FIFO)
   3. Most Frequently Used (MFU)
   4. Least Recently Used (LRU)

   Explanation: The Least Recently Used algorithm evicts the page that has gone unused the longest. FIFO chooses by order of entry, not usage, and MFU removes often-used pages, which is not standard practice. Optimal Replacement isn't based strictly on past usage but predicts future accesses.

5. Handling Repeated Page Faults

   If a process continually generates page faults without any progress, which condition is most likely occurring?

   1. Bootstrapping
   2. Caching
   3. Thrashing
   4. Fragmentation

   Explanation: Thrashing happens when the system spends most of its time handling page faults rather than executing processes, often due to insufficient memory. Caching is about speeding up accesses, fragmentation deals with space allocation, and bootstrapping refers to starting the system.

6. Example of a Minor Page Fault

   Which scenario represents a minor (soft) page fault?

   1. The required page is already in memory but not mapped to the process
   2. The operating system is restarted
   3. A process tries to access a page not in secondary storage
   4. A hardware error occurs while accessing a page

   Explanation: A minor page fault happens when the desired page is in physical memory but isn't mapped for the process. If not present in secondary storage, it's a major issue. Hardware errors aren't page faults, and restarting the OS isn't related.

7. Valid Memory Reference

   A page fault cannot occur if which of the following is true?

   1. The system is idle
   2. The disk is full
   3. All required pages are already in physical memory
   4. The process uses shared memory

   Explanation: If all required pages are in RAM, page faults will not occur. Disk fullness doesn't directly cause or prevent page faults, using shared memory does not inherently prevent faults, and an idle system could still have faults depending on activity.

8. Page Table Role

   What is the primary purpose of the page table in memory management?

   1. To schedule process execution
   2. To map virtual addresses to physical addresses
   3. To allocate disk space for new files
   4. To encrypt memory contents

   Explanation: The page table translates virtual memory addresses to physical memory locations, essential for correct execution. Allocating disk space is part of file systems, process scheduling is done by the scheduler, and encrypting memory is unrelated.

9. Effect of Efficient Page Fault Handling

   Efficient handling of page faults in an operating system primarily results in which benefit?

   1. Increased battery life only
   2. Lower hardware costs
   3. Improved system performance
   4. Larger hard drive space

   Explanation: Quickly resolving page faults reduces process wait times and enhances performance. It does not directly affect hardware costs or hard drive size. Increased battery life may be a secondary benefit, not the central effect.

10. Demand Paging Definition

    What does 'demand paging' mean in the context of page faults?

    1. Memory is divided into variable-sized units
    2. Pages are permanently kept in RAM
    3. Every page is loaded at program start
    4. Pages are loaded into memory only when they are needed

    Explanation: Demand paging means loading pages into memory only when a process tries to access them, helping save memory and reduce startup times. Loading every page at start is pre-paging, not demand paging. Keeping all pages in RAM at all times isn't feasible, and variable-sized units describe segmentation, not paging.