chapter 3

Question 1

the process of changing the address of an instruction or data item to the address in main memory at which it is to be loaded or relocated.

Answer 1

address resolution

Question 2

the name given to several registers, allocated to each active process, whose contents associate several of the process segments and page numbers with their main memory addresses.

Answer 2

associative memory

Question 3

a small, fast memory used to hold selected data and to provide faster access than would otherwise be possible.

Answer 3

cache memory

Question 4

the elapsed time between two ticks of the computer’s system clock.

Answer 4

clock cycle

Question 5

a variation of the LRU policy that removes from the main
the memory of the pages that show the least amount of activity during recent clock cycles.

Answer 5

clock page replacement policy

Question 6

a memory allocation scheme that loads a program’s page into mem- ory at the time it is needed for processing.

Answer 6

demand paging

Question 7

in a paged or segmented memory allocation environment, the difference between a page’s relative address and the actual machine language address. Also called offset.

Answer 7

displacement

Question 8

an unusual circumstance through which adding more page frames causes an increase in page interrupts when using a FIFO page replacement policy.

Answer 8

FIFO anomaly

Question 9

a page replacement policy that removes from main memory the pages that were brought in first.

Answer 9

first-in first-out (FIFO) policy

Question 10

a table in main memory that contains two values for each active job— the size of the job and the memory location where its page map table is stored.

Answer 10

Job Table (JT)

Question 11

a page-replacement policy that removes from main memory the pages that show the least amount of recent activity.

Answer 11

least recently used (LRU) policy

Question 12

behavior observed in many executing programs in which memory locations recently referenced, and those near them, are likely to be referenced in the near future.

Answer 12

locality of reference

Question 13

a table in main memory that contains as many entries as there are page frames and lists the location and free/busy status for each one.

Answer 13

Memory Map Table (MMT)

Question 14

offset

Answer 14

see displacement.

Question 15

a fixed-size section of a user’s job that corresponds in size to page frames in main
memory.

Answer 15

page

Question 16

a type of hardware interrupt caused by a reference to a page not residing in memory. The effect is to move a page out of main memory and into secondary storage so another page can be moved into memory.

Answer 16

page fault

Question 17

the part of the Memory Manager that determines if there are empty page frames in memory so that the requested page can be immediately copied from secondary storage, or determines which page must be swapped out if all page frames are busy. Also known as a page interrupt handler.

Answer 17

page fault handler

Question 18

an individual section of main memory of uniform size into which a single page may be loaded without causing external fragmentation.

Answer 18

page frame

Question 19

a table in main memory with the vital information for each page including the page number and its corresponding page frame memory address.

Answer 19

Page Map Table (PMT)

Question 20

an algorithm used by virtual memory systems to decide which page or segment to remove from main memory when a page frame is needed and memory is full.

Answer 20

page replacement policy

Question 21

the process of moving a page out of main memory and into secondary storage so another page can be moved into memory in its place.

Answer 21

page swapping

Question 22

a memory allocation scheme based on the concept of divid- ing a user’s job into sections of equal size to allow for noncontiguous program storage during execution.

Answer 22

paged memory allocation

Question 23

code that can be used by two or more processes at the same time; each shares the same copy of the executable code but has separate data areas.

Answer 23

reentrant code

Question 24

a division in a disk’s track, sometimes called a “block.” The tracks are divided into sectors during the formatting process.

Answer 24

sector

Question 25

a variable-size section of a user’s job that contains a logical grouping of code.

Answer 25

segment

Question 26

a table in main memory with the vital information for
each segment including the segment number and its corresponding memory address.

Answer 26

Segment Map Table (SMT)

Question 27

a memory allocation scheme based on the concept of dividing a user’s job into logical groupings of code and loading them into memory as needed to minimize fragmentation.

Answer 27

segmented/demand paged memory allocation

Question 28

a memory allocation scheme based on the concept of dividing a user’s job into logical groupings of code to allow for noncontiguous pro- gram storage during execution.

Answer 28

segmented memory allocation

Question 29

also called a “subprogram,” a segment of a program that can perform a specific function. Subroutines can reduce programming time when a specific function is required at more than one point in a program.

Answer 29

subroutine

Question 30

a phenomenon in a virtual memory system where an excessive amount of page swapping back and forth between main memory and secondary storage results in higher overhead and little useful work.

Answer 30

thrashing

Question 31

a technique that allows programs to be executed even though they are not stored entirely in memory.

Answer 31

virtual memory

Question 32

a collection of pages to be kept in main memory for each active process in a virtual memory environment.

Answer 32

working set