Virtual Memory: Extending the Reach of Physical Memory

Question 1

Which of the following is a potential drawback of using a paging system?

Accepted Answer

Increased memory overhead

Answer

Reduced memory efficiency

Answer

Decreased processor utilization

Answer

Faster memory access time

Question 2

What is the term used to describe a program repeatedly accessing the same page over a short duration?

Accepted Answer

Locality of reference

Answer

Page fault

Answer

Thrashing

Answer

Memory leak

Question 3

What is the primary cause of thrashing in a virtual memory system?

Accepted Answer

Insufficient physical memory to hold active pages

Answer

Inefficient page replacement algorithm

Answer

Excessive page size

Answer

Excessive page table size

Question 4

What is the key difference between demand paging and pre-paging in virtual memory?

Accepted Answer

Demand paging brings pages into memory only when needed, while pre-paging brings them in proactively.

Answer

Demand paging uses large page sizes, while pre-paging uses small page sizes.

Answer

Demand paging is more efficient for random memory access patterns, while pre-paging is better for sequential access patterns.

Answer

Demand paging requires a hardware memory management unit, while pre-paging does not.

Question 5

Which page replacement algorithm theoretically achieves the lowest page fault rate?

Accepted Answer

Optimal Page Replacement (OPR)

Answer

Least Recently Used (LRU)

Answer

First-In First-Out (FIFO)

Answer

Clock Page Replacement

Question 6

Which of the following is NOT a key benefit of virtual memory in an operating system?

Accepted Answer

Guarantees that all page faults will be eliminated

Answer

Extends the reach of physical memory

Answer

Improves memory utilization

Answer

Supports concurrent execution of multiple processes

Question 7

Which page replacement algorithm is known for its simplicity and low overhead, making it suitable for real-time systems?

Accepted Answer

First-In, First-Out (FIFO)

Answer

Least Recently Used (LRU)

Answer

Optimal Page Replacement (OPT)

Answer

Clock Page Replacement

Question 8

What is a major concern associated with using the Least Recently Used (LRU) page replacement algorithm?

Accepted Answer

It can lead to a phenomenon known as thrashing, where the system spends excessive time paging data in and out of memory

Answer

It has a high memory overhead due to maintaining a detailed history of page usage

Answer

It is not optimal in all cases, and its performance can vary depending on the workload

Answer

It is difficult to implement efficiently in hardware

Question 9

Which virtual memory technique relies on a dedicated hardware component to efficiently translate virtual addresses to physical addresses?

Accepted Answer

Translation Lookaside Buffer (TLB)

Answer

Segmentation

Answer

Paging

Answer

Inverted Page Table

Question 10

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

Accepted Answer

To establish the mapping between virtual addresses and their corresponding physical addresses

Answer

To store the actual contents of memory pages

Answer

To manage the allocation and deallocation of physical memory

Answer

To track the usage and status of memory pages

Question 11

Which of the following is NOT a factor that can influence the effectiveness of a page replacement algorithm?

Accepted Answer

The number of registers available

Answer

The pattern of memory references

Answer

The frequency of memory accesses

Answer

The page size

Question 12

What is the primary objective of the Working Set Model in virtual memory management?

Accepted Answer

To predict the set of pages that a program is likely to access in the near future

Answer

To eliminate page faults completely

Answer

To improve the performance of all page replacement algorithms

Answer

To reduce the size of the memory footprint of a process

Question 13

Which of the following is a primary advantage of employing virtual memory?

Accepted Answer

Extends the reach of physical memory

Answer

Eliminates the requirement for swapping

Answer

Improves cache efficiency

Answer

Reduces memory access time

Question 14

What is the name of the process that replaces a page in memory with a new one?

Accepted Answer

Page replacement

Answer

Page allocation

Answer

Page swapping

Answer

Page mapping

Question 15

Which page replacement algorithm replaces the page that has been unused for the longest period?

Accepted Answer

Least Recently Used (LRU)

Answer

Most Recently Used (MRU)

Answer

First In First Out (FIFO)

Answer

Clock

Question 16

Which page replacement algorithm aims to replace the page that has been unused for the longest duration?

Accepted Answer

Least Recently Used (LRU)

Answer

Most Recently Used (MRU)

Answer

First-In First-Out (FIFO)

Answer

Least Frequently Used (LFU)

Question 17

What transpires when a hard page fault occurs?

Accepted Answer

The operating system retrieves the page from disk, loading it into memory

Answer

The operating system terminates the process

Answer

The operating system disregards the page fault

Answer

The operating system swaps out a different page to create space

Question 18

Which fundamental mechanism does the operating system primarily employ to manage virtual memory?

Accepted Answer

Demand paging

Answer

Time sharing

Answer

Multitasking

Answer

Virtualization

Question 19

What is the primary function of the page table in the context of virtual memory management?

Accepted Answer

Tracking the location of pages within memory

Answer

Determining the access privileges associated with each page

Answer

Managing the allocation and deallocation of pages

Answer

Handling page faults

Question 20

What is the term for the process of substituting a page in memory with a new one?

Accepted Answer

Page replacement

Answer

Page fault

Answer

Page swapping

Answer

Page buffering

Question 21

Which page replacement algorithm selects the page that has been dormant for the longest duration?

Accepted Answer

Least Recently Used (LRU)

Answer

First-In First-Out (FIFO)

Answer

Optimal

Answer

Clock

Question 22

What is the function of a page table?

Accepted Answer

Maps virtual addresses to physical addresses

Answer

Stores page contents in memory

Answer

Manages physical memory allocation

Answer

Prevents unauthorized memory access

Question 23

What is a key advantage of combining segmentation with virtual memory?

Accepted Answer

Enables different program sections to have varying protection levels.

Answer

Simplifies memory management.

Answer

Reduces memory fragmentation.

Answer

Enhances cache performance.

Question 24

What is the primary purpose of a Translation Lookaside Buffer (TLB)?

Accepted Answer

Stores frequently used page table entries

Answer

Accelerates virtual address translation

Answer

Prevents unauthorized memory access

Answer

Manages physical memory allocation

Question 25

What is the primary purpose of a page replacement algorithm?

Accepted Answer

To determine which pages to remove from physical memory when needed

Answer

To create new pages in virtual memory

Answer

To manage the mapping between virtual and physical memory

Answer

To allocate physical memory to processes

Question 26

What is the key difference between demand paging and pre-paging virtual memory systems?

Accepted Answer

Demand paging only brings pages into memory when they are needed, while pre-paging brings all pages into memory upfront.

Answer

Demand paging creates a copy of each page in virtual memory, while pre-paging creates a copy in physical memory.

Answer

Demand paging uses a stack, while pre-paging uses a queue to manage virtual memory.

Answer

Demand paging is typically faster than pre-paging.

Question 27

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

Accepted Answer

To translate virtual memory addresses to physical memory addresses

Answer

To manage the allocation and deallocation of virtual pages

Answer

To provide memory protection by enforcing access permissions

Answer

To implement page replacement algorithms

Question 28

In modern operating systems, how does virtual memory find practical application?

Accepted Answer

Virtual memory enables multiple applications to run simultaneously on personal computers despite limited physical memory.

Answer

Virtual memory is primarily utilized in supercomputers to handle vast datasets that surpass the system's physical memory capacity.

Answer

Virtual memory is not relevant in cloud servers due to their ample physical memory.

Answer

Virtual memory is exclusively employed in embedded systems to address their inherent memory limitations.

Question 29

What is the purpose of a page fault in virtual memory?

Accepted Answer

To notify the operating system that a requested page is not in physical memory.

Answer

To allocate a physical memory frame for a page.

Answer

To replace an existing page in physical memory.

Answer

To prevent access to unauthorized memory.

Question 30

Which page replacement algorithm is commonly used to minimize the number of page faults?

Accepted Answer

Least Recently Used (LRU)

Answer

Optimal

Answer

First-In First-Out (FIFO)

Answer

Clock

Question 31

What is the primary function of the page table in virtual memory?

Accepted Answer

To translate virtual addresses to physical addresses.

Answer

To store the physical memory frames assigned to pages.

Answer

To manage the allocation and deallocation of page frames.

Answer

To prevent unauthorized access to virtual memory.

Question 32

What is the key difference between logical and physical memory addresses?

Accepted Answer

Logical addresses are relative to the program, while physical addresses are absolute in memory.

Answer

Physical addresses are relative to the program, while logical addresses are absolute in memory.

Answer

Logical addresses are used by the operating system, while physical addresses are used by hardware.

Answer

Physical addresses are used by the operating system, while logical addresses are used by hardware.

Question 33

What is the concept of thrashing in virtual memory?

Accepted Answer

A situation where the operating system spends excessive time paging instead of executing instructions.

Answer

A technique used to improve the performance of virtual memory.

Answer

A type of memory leak that can occur in virtual memory systems.

Answer

A security vulnerability that can be exploited through virtual memory.

Question 34

What is the primary goal of virtual memory?

Accepted Answer

To extend the effective capacity of physical memory

Answer

To improve security

Answer

To increase memory performance

Answer

To reduce memory costs

Question 35

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

Accepted Answer

To translate virtual addresses to physical addresses

Answer

To store the contents of a page in memory

Answer

To determine which pages to replace when needed

Answer

To handle page faults

Question 36

What occurs when a page fault happens in a virtual memory system?

Accepted Answer

The running program is suspended, and the missing page is loaded into memory

Answer

The operating system terminates the running program

Answer

The operating system displays an error message

Answer

The operating system ignores the page fault

Question 37

Which of the following metrics is used to evaluate the effectiveness of a page replacement algorithm?

Accepted Answer

Page fault rate

Answer

Memory usage

Answer

Processor utilization

Answer

Disk I/O rate

Question 38

What is the role of the Translation Lookaside Buffer (TLB) in virtual memory management?

Accepted Answer

To cache recently translated virtual addresses

Answer

To handle page faults

Answer

To manage the allocation of physical memory

Answer

To store the contents of a page table

Question 39

Which of the following techniques is used to proactively reduce page faults?

Accepted Answer

Prefetching

Answer

Demand paging

Answer

Buddy system

Answer

Segmentation

Question 40

What is the primary difference between a hard page fault and a soft page fault?

Accepted Answer

A hard page fault requires I/O to retrieve the missing page, while a soft page fault does not

Answer

A soft page fault requires I/O to retrieve the missing page, while a hard page fault does not

Answer

A hard page fault is caused by a protection violation, while a soft page fault is not

Answer

A soft page fault is caused by a protection violation, while a hard page fault is not

Question 41

Which of the following is NOT a benefit of using virtual memory?

Accepted Answer

Increased memory access time

Answer

Enhanced process isolation

Answer

Improved performance for memory-intensive applications

Answer

Extended physical memory capacity

Question 42

What is the commonly used page size in virtual memory implementations?

Accepted Answer

4 KB

Answer

8 KB

Answer

16 KB

Answer

1 KB

Question 43

Which page replacement algorithm prioritizes fairness and efficiency by selecting the page that has been least recently used?

Accepted Answer

LRU (Least Recently Used)

Answer

FIFO (First In First Out)

Answer

LRU-K (Least Recently Used with K bits)

Answer

OPT (Optimal)

Question 44

What is the primary function of the page fault handler in virtual memory?

Accepted Answer

To retrieve the required page from secondary storage into physical memory when a page fault occurs

Answer

To allocate a new page frame for the page fault

Answer

To terminate the process that triggered the page fault

Question 45

Which of the following is an advantage of a hardware-based page table over a software-based page table?

Accepted Answer

Faster page table lookups

Answer

Lower implementation cost

Answer

Reduced memory overhead

Answer

Enhanced security

Question 46

What is the primary purpose of a TLB (Translation Lookaside Buffer)?

Accepted Answer

To accelerate page table lookups by caching frequently accessed page table entries

Answer

To store the entire page table in faster memory

Answer

To manage the allocation and deallocation of physical pages

Question 47

What is the primary benefit of using virtual memory?

Accepted Answer

Extends the reach of physical memory, allowing for processes to use more memory than physically available.

Answer

Increases the speed of data access in all cases.

Answer

Reduces the need for secondary storage.

Question 48

A page fault occurs when:

Accepted Answer

The requested page is not present in physical memory.

Answer

The operating system runs out of available memory slots in the page table.

Answer

The CPU encounters an error during instruction execution.

Question 49

What is the purpose of a Translation Lookaside Buffer (TLB)?

Accepted Answer

To speed up address translation by caching recently used page table entries.

Answer

To handle page faults and swap pages between memory and disk.

Answer

To manage the allocation of physical memory pages.

Question 50

Which page replacement algorithm is considered optimal but impractical to implement in real systems?

Accepted Answer

Optimal Page Replacement (OPT)

Answer

Second Chance Algorithm

Answer

Least Recently Used (LRU)

Answer

First-In, First-Out (FIFO)

Question 51

Consider a system with a physical memory of 4 GB and a virtual memory of 16 GB. What is the maximum number of pages that can be in physical memory at any given time?

Accepted Answer

It depends on the page size.

Answer

The number of processes running in the system.

Answer

4 GB

Answer

16 GB

Question 52

How does the use of virtual memory affect the overall performance of a system?

Accepted Answer

It can increase performance by allowing more processes to run concurrently, but it can also introduce overhead due to page faults and context switching.

Answer

It consistently improves performance by providing more memory without introducing overheads.

Question 53

Which page replacement algorithm is known to suffer from the Belady's Anomaly, where increasing the number of page frames can lead to an increase in page faults?

Accepted Answer

First-In, First-Out (FIFO)

Answer

Second Chance Algorithm

Answer

Optimal Page Replacement (OPT)

Answer

Least Recently Used (LRU)

Question 54

A process is currently using 10 pages of virtual memory. If the page size is 4 KB, what is the total virtual memory size allocated to this process?

Accepted Answer

40 KB

Answer

10 KB

Answer

4 KB