Memory Management

Question 1

what is paging?

Answer 1

where memory is split into blocks of a fixed size with physical division
programs are split into fixed sizes which can then be easily slotted into any free spaces in RAM

Question 2

Advantage of paging

Answer 2

incredibly simple, just break up the memory into fixed chunks

Question 3

Disadvantage of paging

Answer 3

ignores programs structure/flow
loops and large data structures can end up going into multiple pages and end up jumping into RAM

Question 4

What is segmentation?

Answer 4

where programs are broken up into logical divisions
each block has a varying size
could be split into segments such as instructions and data

Question 5

Advantage of segmentation

Answer 5

keeps major sections of the program together reducing inconvenient jumps around RAM

Question 6

Disadvantage of segmentation

Answer 6

complicated to know where to split programs up

Question 7

Paging and segmentation

Answer 7

no reason cant use both
in a modern OS the smallest size a segment can be is the size of a single page
e.g windows and linux default page size in 4kib

Question 8

Paging and segmentation disadvantage

Answer 8

will be wasted space if a processor doesn’t use an entire page of memory as only one process can exist in a single page

Question 9

What is virtual memory?

Answer 9

enables the use of secondary storage to store loaded programs that are not currently being executed
as secondary storage has significantly more storage capacity than RAM we can also load massive programs
we do this by moving pages into seconday storage

Question 10

Advantage of virtual memory

Answer 10

allows programs that wouldn’t normally fit into RAM to still be executed

Question 11

Disadvantages of virtual memory

Answer 11

incredibly slow (secondary storage is significantly slower than RAM)
if being used a lot it can significantly shorten the lifespan of secondary storage device, storage thrashing