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Question 1

What does memory management do?

Answer 1

Brings processes together in main memory for execution

Question 2

What does memory management rely on?

Answer 2

Virtual memory segmentation and paging

Question 3

What is a hard/fixed partition?

Answer 3

Applications cannot change the size of their memory partitions. The partitions are made in OS design

Question 4

In hard partitions, how are applications designed if they need more memory?

Answer 4

They are designed to work around the partitions. It’s the programmer’s job

Question 5

When can the OS swap things in a fixed partition?

Answer 5

If all partitions are full and none are ready or running

Question 6

What is the major problem with a fixed partition?

Answer 6

If a program cannot fit into a partitions, it needs to use overlays

Question 7

Why is fixed partition inefficient?

Answer 7

A program can occupy a whole partition if it does not need all that space. This is called internal fragmentation

Question 8

What is unequal size partitions?

Answer 8

The remedy for fixed partitioning. Larger programs can be accommodated without overlays.

Question 9

What happens to smaller programs in unequal size partitions?

Answer 9

They use memory inefficiently

Question 10

What limits processes in unequal sized partitions?

Answer 10

The max amount of partitions

Question 11

What is dynamic partitioning?

Answer 11

Partitions are of varying size and number. Processes get as much memory as they need

Question 12

What is external fragmentation?

Answer 12

Dynamically partitioned memory becomes more and more fragmented and utilization declines. Not enough contiguous space to run a process.

Question 13

What is compaction?

Answer 13

The OS addresses fragmentation by shifting processes so that they are are contiguous. But it wastes CPU time.

Question 14

Best Fit Placement Algorithm

Answer 14

A block is chosen closest to the request size

Question 15

First Fit Placement Algorithm

Answer 15

Selects the first block that is big enough to accommodate a process

Question 16

Next Fit Placement Algorithm

Answer 16

Starts looking for the next block that is large enough from the last placement

Question 17

What is the buddy system?

Answer 17

A hybrid of fixed and dynamic partitioning schemes.

Question 18

What happens to available space in the buddy system?

Answer 18

It is all treated as a single block

Question 19

Logical Address

Answer 19

Reference to a memory location independent of the current assignment of data to memory

Question 20

Relative Address

Answer 20

Address is expressed relative to some known point

Question 21

Physical/Absolute Address

Answer 21

Address is that of the actual location in main memory

Question 22

How does a virtual memory system work?

Answer 22

A small portion of a program is loaded into memory to increase multiprogramming. And there are pointers to secondary memory

Question 23

What is a problem with virtual memory?

Answer 23

Hard drives are slow

Question 24

What is paging?

Answer 24

You partition memory into equal size chunks that relatively small, and the process is divided into small chunks the same size of the pages

Question 25

What exactly is a page?

Answer 25

A chunk of a process

Question 26

What exactly is a frame?

Answer 26

Available chunks of memory

Question 27

Why are pages designed to be small?

Answer 27

To avoid fragmentation

Question 28

What is the page table?

Answer 28

Contains the frame location for each page in a process. Maintained by the OS and the processor must know how to access the current process and produce a phys. address