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Question 1 of 60 Quiz ID: q1

What is the primary benefit of virtual memory according to the lecture?

Faster CPU execution speed

Separation of user logical memory from physical memory

Reduced power consumption

Better graphics performance

Question 2 of 60 Quiz ID: q2

Which of the following is NOT a benefit of virtual memory mentioned in the lecture?

Logical address space can be much larger than physical address space

Allows address spaces to be shared by several processes

Reduces the need for secondary storage

Allows for more efficient process creation

Question 3 of 60 Quiz ID: q3

Virtual memory can be implemented via which two methods?

Demand paging and demand segmentation

Static allocation and dynamic allocation

Sequential access and random access

Buffering and caching

Question 4 of 60 Quiz ID: q4

In virtual address space design, where does the stack typically start?

At address 0

At the middle of address space

At the maximum logical address and grows down

At a random location

Question 5 of 60 Quiz ID: q5

What is the main advantage of having unused address space between stack and heap?

Faster memory access

No physical memory needed until heap or stack grows to a given new page

Better security

Reduced fragmentation

Question 6 of 60 Quiz ID: q6

What is demand paging?

Loading the entire process into memory at startup

Bringing a page into memory only when it is needed

Allocating memory in fixed-size chunks

Compressing memory pages

Question 7 of 60 Quiz ID: q7

What are the benefits of demand paging compared to loading entire processes?

Less I/O needed, less memory needed, faster response, more users

Better graphics, faster CPU, more storage

Reduced power consumption, better security

Simplified programming, easier debugging

Question 8 of 60 Quiz ID: q8

What is a lazy swapper in the context of demand paging?

A swapper that works slowly

A swapper that never swaps a page into memory unless the page will be needed

A swapper that only works during idle time

A swapper that compresses pages

Question 9 of 60 Quiz ID: q9

In the valid-invalid bit scheme, what does 'v' represent?

Virtual memory

Valid page reference

In-memory (memory resident)

Variable size page

Question 10 of 60 Quiz ID: q10

What happens when the MMU encounters an 'i' bit during address translation?

The page is immediately loaded

A page fault occurs

The process is terminated

Memory is compressed

Question 11 of 60 Quiz ID: q11

What is the first step in handling a page fault?

Find a free frame

Reference to a page traps to the operating system

Reset the page tables

Swap the page into memory

Question 12 of 60 Quiz ID: q12

After a page fault occurs and the OS determines it's a valid reference, what is the next step?

Restart the instruction

Find free frame

Reset validation bit

Terminate the process

Question 13 of 60 Quiz ID: q13

What is pure demand paging?

Loading all pages at once

Starting a process with no pages in memory

Using only physical memory

Compressing all pages

Question 14 of 60 Quiz ID: q14

What hardware support is needed for demand paging?

Page table with valid/invalid bit, secondary memory, instruction restart

Cache memory, faster CPU, more registers

Graphics card, sound card, network card

Floating point unit, vector processor

Question 15 of 60 Quiz ID: q15

What is a free-frame list?

A list of processes waiting for memory

A pool of free frames for satisfying page fault requests

A list of pages to be swapped out

A directory of memory locations

Question 16 of 60 Quiz ID: q16

What is zero-fill-on-demand?

Filling memory with random data

Zeroing out frame contents before allocation

Filling frames with program code

Creating empty files

Question 17 of 60 Quiz ID: q17

According to the performance example, if memory access time is 200 nanoseconds and average page-fault service time is 8 milliseconds, what is the EAT when p = 1/1000?

200 nanoseconds

8.2 microseconds

8 milliseconds

1000 nanoseconds

Question 18 of 60 Quiz ID: q18

For performance degradation less than 10%, what should be the maximum page fault rate?

Less than 1 page fault in every 1,000 accesses

Less than 1 page fault in every 400,000 accesses

Less than 1 page fault in every 100 accesses

Less than 1 page fault in every 10,000 accesses

Question 19 of 60 Quiz ID: q19

What is Copy-on-Write (COW)?

A method to copy files between processes

Allowing parent and child processes to initially share pages, copying only when modified

A technique to write data to multiple locations

A backup mechanism for virtual memory

Question 20 of 60 Quiz ID: q20

Why is Copy-on-Write more efficient for process creation?

It uses less CPU time

Only modified pages are copied

It requires less disk space

It uses fewer system calls

Question 21 of 60 Quiz ID: q21

What is vfork()?

A system call to create virtual memory

A variation on fork() where parent suspends and child uses copy-on-write address space

A method to allocate virtual frames

A technique to validate memory pages

Question 22 of 60 Quiz ID: q22

What happens when there is no free frame available for a page fault?

The process is terminated

Page replacement must occur

The system crashes

Memory is automatically expanded

Question 23 of 60 Quiz ID: q23

What is the purpose of the modify (dirty) bit in page replacement?

To identify invalid pages

To reduce overhead of page transfers by only writing modified pages to disk

To mark pages for compression

To indicate page access frequency

Question 24 of 60 Quiz ID: q24

What are the basic steps in page replacement?

Find desired page, find free frame, bring page in, continue process

Compress memory, allocate space, load page, restart

Terminate process, clean memory, restart system

Save state, find victim, swap out, swap in

Question 25 of 60 Quiz ID: q25

In the FIFO page replacement algorithm, how many page faults occur with the reference string 7,0,1,2,0,3,0,4,2,3,0,3,0,3,2,1,2,0,1,7,0,1 using 3 frames?

Question 26 of 60 Quiz ID: q26

What is Belady's Anomaly?

More frames always result in fewer page faults

Adding more frames can cause more page faults

Page replacement algorithms are inefficient

Virtual memory causes system crashes

Question 27 of 60 Quiz ID: q27

What is the optimal page replacement algorithm?

Replace the page that was least recently used

Replace the page that arrived first

Replace the page that will not be used for the longest period of time

Replace the page with the lowest address

Question 28 of 60 Quiz ID: q28

How many page faults does the optimal algorithm produce with the given reference string and 3 frames?

Question 29 of 60 Quiz ID: q29

What does the LRU (Least Recently Used) algorithm replace?

The page that arrived first

The page that will not be used for longest time

The page that has not been used in the most amount of time

The page with the lowest reference count

Question 30 of 60 Quiz ID: q30

How many page faults does LRU produce with the reference string using 3 frames?

Question 31 of 60 Quiz ID: q31

What are two implementation approaches for LRU?

Counter implementation and stack implementation

Array implementation and linked list implementation

Hardware implementation and software implementation

Sequential implementation and parallel implementation

Question 32 of 60 Quiz ID: q32

What is the main problem with LRU implementation?

It produces too many page faults

It needs special hardware and is still slow

It cannot handle large page sizes

It is incompatible with virtual memory

Question 33 of 60 Quiz ID: q33

What is the reference bit in LRU approximation?

A bit that counts references to a page

A bit associated with each page, initially 0, set to 1 when page is referenced

A bit that indicates page validity

A bit that shows page modification status

Question 34 of 60 Quiz ID: q34

What is the second-chance algorithm?

A variation of optimal algorithm

Generally FIFO, plus hardware-provided reference bit

A hardware-based LRU implementation

A compression-based replacement algorithm

Question 35 of 60 Quiz ID: q35

In the enhanced second-chance algorithm, which page category is best to replace?

(1,1) recently used and modified

(1,0) recently used but clean

(0,1) not recently used but modified

(0,0) neither recently used nor modified

Question 36 of 60 Quiz ID: q36

What does LFU (Least Frequently Used) algorithm replace?

The page with the largest reference count

The page with the smallest reference count

The page that was least recently used

The page that arrived first

Question 37 of 60 Quiz ID: q37

What is the main benefit of page-buffering algorithms?

They eliminate page faults entirely

Keep a pool of free frames so frames are available when needed

They compress memory pages

They predict future page references

Question 38 of 60 Quiz ID: q38

What is the minimum number of frames each process needs?

At least 1 frame

Depends on the instruction set architecture

At least 10 frames

Depends on the process size

Question 39 of 60 Quiz ID: q39

In fixed allocation, what is equal allocation?

Each process gets frames proportional to its size

Each process gets the same number of frames

Each process gets frames based on priority

Each process gets frames based on CPU usage

Question 40 of 60 Quiz ID: q40

What is the formula for proportional allocation?

ai = (si/S) × m

ai = si × m

ai = m/si

ai = S/si

Question 41 of 60 Quiz ID: q41

What is global replacement?

Process selects replacement frame from only its own allocated frames

Process selects replacement frame from the set of all frames

All processes share the same replacement algorithm

Replacement occurs globally across all systems

Question 42 of 60 Quiz ID: q42

What is an advantage of local replacement over global replacement?

Higher throughput

More consistent per-process performance

Better memory utilization

Faster execution time

Question 43 of 60 Quiz ID: q43

What is thrashing?

A process using too much CPU time

A process is busy swapping pages in and out

Multiple processes competing for resources

System running out of disk space

Question 44 of 60 Quiz ID: q44

What causes thrashing according to the lecture?

Too many processes running

Insufficient CPU power

Size of locality > total memory size

Poor programming practices

Question 45 of 60 Quiz ID: q45

What is the working-set model?

A model for CPU scheduling

A model using a working-set window (Δ) - a fixed number of page references

A model for disk scheduling

A model for process synchronization

Question 46 of 60 Quiz ID: q46

What is WSSi in the working-set model?

Working set size of all processes

Working set of Process Pi - total number of pages referenced in the most recent Δ

Window size for process i

Wait state for process i

Question 47 of 60 Quiz ID: q47

According to the working-set model, what happens if D > m?

System performance improves

Thrashing occurs

More processes can be added

Memory is automatically expanded

Question 48 of 60 Quiz ID: q48

What is Page-Fault Frequency (PFF)?

A more direct approach than working-set model

A method to increase page faults

A scheduling algorithm

A memory allocation technique

Question 49 of 60 Quiz ID: q49

Why is kernel memory treated differently from user memory?

Kernel memory is faster

Kernel requests memory for structures of varying sizes, and some needs to be contiguous

Kernel memory is more secure

Kernel memory uses different hardware

Question 50 of 60 Quiz ID: q50

What is the buddy system?

A system for sharing memory between processes

Memory allocated using power-of-2 allocator

A backup memory system

A system for memory compression

Question 51 of 60 Quiz ID: q51

What is a disadvantage of the buddy system?

Slow allocation speed

Fragmentation

High memory overhead

Complex implementation

Question 52 of 60 Quiz ID: q52

What is a slab in the slab allocator?

A type of memory controller

One or more physically contiguous pages

A compression algorithm

A scheduling policy

Question 53 of 60 Quiz ID: q53

What are the benefits of the slab allocator?

Faster CPU performance

No fragmentation, fast memory request satisfaction

Better graphics performance

Reduced power consumption

Question 54 of 60 Quiz ID: q54

What is prepaging?

Removing pages from memory

Prepaging all or some of the pages a process will need before they are referenced

Compressing pages before storage

Validating page references

Question 55 of 60 Quiz ID: q55

What factors must be considered in page size selection?

Fragmentation, page table size, resolution, I/O overhead

CPU speed, memory speed, disk speed

Process priority, user preferences, system load

Network bandwidth, graphics capability

Question 56 of 60 Quiz ID: q56

What is TLB Reach?

The distance TLB can access

The amount of memory accessible from the TLB

The number of TLB entries

The speed of TLB access

Question 57 of 60 Quiz ID: q57

In the program structure example, why does Program 2 have fewer page faults than Program 1?

Program 2 uses less memory

Program 2 accesses array elements in row-major order, following memory layout

Program 2 has better optimization

Program 2 runs faster

Question 58 of 60 Quiz ID: q58

What is I/O interlock?

A method to speed up I/O operations

Pages must sometimes be locked into memory during I/O operations

A synchronization mechanism for I/O

A technique to reduce I/O overhead

Question 59 of 60 Quiz ID: q59

What technique does Windows use for virtual memory management?

Pure demand paging

Demand paging with clustering

Segmentation only

Static allocation

Question 60 of 60 Quiz ID: q60

In Solaris virtual memory management, what is the purpose of the pageout process?

To allocate new pages to processes

To perform paging using modified clock algorithm

To compress memory pages

To schedule process execution

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