Deck 3: Memory Management: Virtual Memory Systems

Question 1

With demand paging,if there are no empty page frames available,to move in a new page,one of the current resident pages must be placed into main memory.

Answer 1

False

Question 2

Demand paging introduced the concept of loading only a part of the program into memory for processing

Answer 2

True

Question 3

In a demand paging scheme,the first-in first-out (FIFO)page replacement policy chooses the page least recently accessed to be swapped out.

Answer 3

False

Question 4

The optimal selection of cache size and replacement algorithm can result in 80 to 90 percent of all requests being in the cache.

Question 5

Paged memory allocation offers the advantage that it doesn't require the entire job to be stored in memory during its execution.

Question 6

The segmented/demand paged memory allocation scheme is a combination of segmentation and demand paging,and it offers the logical benefits of segmentation,as well as the physical benefits of paging.

Question 7

With segmented memory allocation,each job is divided into several segments of the same size,one for each module containing pieces that perform related functions.

Question 8

The primary advantage of storing programs in noncontiguous page frames (in a paged memory allocation scheme)is that main memory is used more efficiently because an empty page frame can be used by any page of any job.

Question 9

Associative memory is a name given to several hardware registers that are allocated to each active job whose task is to associate segment and page numbers belonging to the job being processed with their main memory addresses.

Question 10

A job's working set is the collection of pages that must be loaded from secondary storage.

Question 11

The key to the successful implementation of demand paging is the use of a high-speed CPU.

Question 12

With demand paging,three additional fields are introduced for each page in each PMT: one to determine if the page being requested is already in memory,a second to determine if the page contents have been modified while in memory,and a third to determine if the page has been referenced most recently.

Question 13

Thrashing is a problem that occurs when there are a large number of jobs and many free pages so that pages are being moved around too much.

Question 14

When using a FIFO scheme,adding more memory always results in better performance.

Question 15

In the bit-shifting variation of the LRU page replacement policy,the process of shifting bits to the right and resetting the leftmost bit to 1 when a page is referenced gives a history of each page's usage.

Question 16

In a paged memory allocation scheme,to find the actual position of an instruction in memory,first the page number and displacement are determined.Then the operating system refers to the job's PMT to correlate the page with its page frame.

Question 17

Virtual memory can be implemented with both paging and segmentation.

Question 18

A variation of the LRU page replacement algorithm known as the clock page replacement policy is implemented using a pointer to step through the reference bits of the active pages,simulating a clockwise motion.

Question 19

Cache memory is based on the concept of using a large,fast,and expensive memory to supplement the workings of main memory.

Question 20

The Job Table (JT)contains two values for each active job: the size of the job and the memory location where its Page Map Table is stored.

Question 21

In demand paging,pages are ____ between main memory and secondary storage.

A) swapped
B) traded
C) allocated
D) faulted

Question 22

The purpose of cache memory is to keep handy the most recently accessed data and instructions so that the CPU can access them repeatedly without wasting time.This purpose is similar to that of the ____ of a Web browser.

A) cache file
B) bookmark file
C) page file
D) block file

Question 23

In a paged memory allocation scheme,the ____ contains two values for each active job: the size of the job and the memory location where its Page Map Table is stored.

A) Memory Management Table
B) Job Table
C) Page Access Table
D) Memory Map Table

Question 24

Cache memory is divided into blocks of equal size called ____.

A) slots
B) pages
C) segments
D) partitions

Question 25

In a paged memory allocation scheme,a page size that is too small will generate ____.

A) very long Page Map Tables
B) excessive internal fragmentation
C) excessive page faults
D) excessive external fragmentation

Question 26

In demand paging,the collection of pages residing in memory that can be accessed directly without incurring a page fault is called the ____.

A) page set
B) working set
C) job set
D) denning set

Question 27

____ effectively removes restrictions on maximum program size.

A) Segmenting
B) Virtual memory
C) Shared memory
D) Multithreading

Question 28

____ can be thought of as being an intermediary between main memory and the special-purpose registers,which are the domain of the CPU.

A) Virtual memory
B) Cache memory
C) Paging
D) Segmenting

Question 29

To access a location in memory when using segmented memory management,the address is composed of two entries: ____.

A) the segment number and the line number
B) the segment number and the displacement
C) the line number and the displacement
D) the segment number, the line number, and the displacement

Question 30

In demand paging schemes,the ____ in a Page Map Table indicates whether the page is currently in memory.

A) referenced bit
B) modified bit
C) memory bit
D) status bit

Question 31

A disadvantage of segmented memory allocation is ____.

A) the physical size requirements of main memory
B) the number of page faults
C) internal fragmentation
D) external fragmentation

Question 32

The primary advantage of storing programs in noncontiguous locations is that ____.

A) multiple programs can run at the same time
B) every program will be able to run
C) secondary storage is accessed more quickly
D) main memory is used more efficiently

Question 33

The ____ demonstrates that when using a FIFO policy,in rare cases,adding more memory to a system can cause an increase in page interrupts.

A) Paging Anomaly
B) Belady Anomaly
C) Interrupt Anomaly
D) Laszlo Anomaly

Question 34

One of the most important innovations of demand paging is that it makes ____ feasible.

A) parallel memory
B) automatic allocation
C) spontaneous allocation
D) virtual memory

Question 35

The term "____" means that during any phase of its execution,a program references only a small fraction of its pages.

A) dynamic paging
B) structured programming
C) locality of reference
D) working set

Question 36

With segmented memory allocation,each job is divided into several ____ of different sizes,one for each module that contains pieces that perform related functions.

A) pages
B) modules
C) segments
D) partitions

Question 37

In a paged memory allocation scheme,a simple ____ has one entry for each page frame that shows its location and its free/busy status.

A) Memory Management Table
B) Job Table
C) Page Access Table
D) Memory Map Table

Question 38

The ____ page replacement policy is based on the theory that the best page to remove is the one that has been in memory the longest.

A) TRU
B) LRU
C) LIFO
D) FIFO

Question 39

A variation of the LRU page replacement algorithm known as the ____ replacement policy is implemented with a circular queue.

A) clock page
B) round robin
C) performance page
D) bit shifting

Question 40

In demand paging,when an excessive number of pages are moved back and forth between main memory and secondary storage,it is called ____.

A) swapping
B) faulting
C) paging
D) thrashing