Module 9: Introduction to Memory Management

Question 1

memory management

Answer 1

the technique for mapping virtual address spaces to physical memory

Question 2

physical memory

Answer 2

memory that is directly accessible to the CPU; operates at high speed, but typically offers lower capacity than storage

Question 3

disk

Answer 3

a storage device that uses a magnetic storage mechanism. not all data fits into physical memory, so the disk holds data until it is pulled into physical memory

Question 4

fixed partition scheme

Answer 4

strategy for translating virtual to physical addresses in which we divide the memory into partitions such that one process is loaded per partition and queue processes that are waiting to be loaded into memory

uses a fixed offset to convert between physical and virtual addresses

Question 5

base and limit registers

Answer 5

strategy for translating virtual to physical addresses in which the base register contains the value that gets added to the virtual address to determine the physical address, and the limit register contains the highest address that the program cannot surpass

requires hardware support to implement

Question 6

bitmaps

Answer 6

in tracking free space in memory, a bitmap is a vector in which each digit is 1 or 0 depending on whether a given memory chunk is free or not

Question 7

linked list

Answer 7

the elements of the LL represent blocks of memory that are free

Question 8

worst-fit

Answer 8

memory allocation scheme that finds the largest block of free memory possible and stores the process in it

Question 9

best fit

Answer 9

memory allocation scheme that finds the smallest hole which is large enough to fit the process and stores the process in it

Question 10

first-fit

Answer 10

memory allocation scheme that puts the process in the first discovered hole of free memory that is large enough to fit the process

Question 11

internal fragmentation

Answer 11

internal to an allocated space, internal fragmentation is where a process is allocated more bytes that it uses

Question 12

external fragmentation

Answer 12

space that the OS is aware of but that is too small to fit new processes

Question 13

page

Answer 13

a continuous portion of memory that is treated by the OS as a single unit of storage

Question 14

slab allocation

Answer 14

break large chunks of memory given to a process by the buddy algo into smaller units for allocation

Question 15

object caches

Answer 15

freed objects are stored in a cache in case they are allocated again, rather than freeing them for allocation to other processes