Memory Management

Question 1

What is the Memory Manager OS responsible for?

Answer 1

• Allocating memory to processes
• Loading and unloading individual processes without impacting others

Question 2

When is memory management used?

Answer 2

To ensure RAM is used efficiently and not wasted.
Otherwise RAM would rapidly run out and fill up with unneeded data so no new applications could run

Question 3

3 types of memory management

Answer 3

1) Paging
2) Segmentation
3) Virtual Memory

Question 4

Paging

Answer 4

• Uses fixed size divisions
• Memory is divided physically
• A page table is used to map page location
• Easier for OS to manage pace locations as they can be stored non-contiguously (not touching each other)

Question 5

Segmentation

Answer 5

• Uses varying size divisions
• Causes external fragmentation
• Works better contiguously
• Errors can cause memory leakage which could cause the system to crash

Question 6

Similarities between paging and segmentation

Answer 6

• Both allow programs to run despite there not being enough memory
• Stored on a disk
• Transferred into memory when needed

Question 7

Differences between paging and segmentation

Answer 7

• Pages are fixed size. Segments are different sizes
• Pages are made to fit sections of memory. Segments are complete sections of programs. Pages are physical divisions. Segments are logical divisions

Question 8

When is virtual memory used?

Answer 8

When RAM is full to enable applications to continue to run

Question 9

How is data transferred between RAM and VM

Answer 9

Data is transferred out of RAM into VM to free up space and then transferred back again when needed

Question 10

Why is VM useful?

Answer 10

RAM is much more expensive so VM saves buying more RAM

Question 11

What happens if you over use VM?

Answer 11

System slows down