Answers to
Chapter 7 Quiz
CIS343
(1-5) Identify the five
requirements that memory management is intended to satisfy.
1. No process should be subject
to unwanted interference from another process, whether accidental or
intentional.
protection
2. Controlled access to shared
areas of memory must be allowed, without compromising essential protection.
sharing
3. Since we cannot know ahead
of time where in memory a program should be placed, and since a program may be
moved from one memory area to another, our memory management must provide
for...
relocation
4. The task of finding areas of
main memory and secondary memory for a program and of moving information
between the two levels of memory.
physical
organization
5. Providing for the programmer
useful concepts for program organization, which may or may not have exact
physical parallels.
logical
organization
(6-11) Identify these memory
management techniques.
6. Main memory is divided into
a number of equal-size frames. Each
process is divided into a number of equal-size units, of the same size as the
frames.
simple
paging
7. Main memory is divided into
a number of static partitions at system generation time.
fixed
partitioning
8. Each process is divided into
a number of segments, not all of which are resident at any one point in time.
virtual
memory segmentation
9. Partitions are created as
needed, so that each process is loaded into a partition of exactly the same
size as the process.
dynamic
partitioning
10. Each process is divided into
a number of segments, all of which are loaded into memory at run time, though
not necessarily contiguously.
simple
segmentation
11. Each process is divided into
frames, some of which, though not all, are resident at run time.
virtual
memory, paging
(12-17) Classify each of
these memory management strategies in one of 4 categories:
I-Y E-Y :: internal fragmentation -
yes; external fragmentation - yes
I-N E-Y :: internal fragmentation -
no; external fragmentation - yes
I-Y E-N :: internal fragmentation -
yes; external fragmentation - no
I-N E-N :: internal fragmentation -
no; external fragmentation - no
12. Fixed partitioning
I-Y E-N
internal
fragmentation; no external fragmentation
13. Dynamic partitioning
I-N E-Y
no
internal fragmentation; external fragmentation
14. Simple paging
I-Y E-N
no
external fragmentation; a small amount of internal fragmentation
15. Simple segmentation
I-N E-Y
no
internal fragmentation; some external fragmentation
16. Virtual memory paging
I-Y E-N
no
external fragmentation; a small amount of internal fragmentation
17. Virtual memory segmentation
I-N E-Y
no
internal fragmentation
(18-20) Describe these terms
related to relocation.
18. Relative address
An address expressed as a location relative to
some known point.
19. Physical address
An absolute address, an actual location in main
memory.
20. Logical address
A reference to a memory location independent of
the current assignment of data to memory.
(21-23) Describe these terms
related to paging and segmentation.
21. Frames
The equal-size chunks that memory is divided
into
22. Pages
The equal-size chunks that a process is divided
into.
23. Segments
The chunks that a program is divided into which
are not necessarily all of the same length.
(24-29) Identify the memory
management technique which has the following strengths (list
all that apply):
24. No internal fragmentation
dynamic
partitioning
simple
paging
virtual
memory, segmentation
25. Higher degree of
multiprogramming
virtual
memory, paging
virtual
memory, segmentation
26. Large virtual address space
virtual
memory, paging
virtual
memory, segmentation
27. Protection and sharing
support
virtual
memory, segmentation
28. Simple to implement; little
OS overhead
fixed
partitioning
29. No external fragmentation
simple
paging
virtual
memory, paging
(30-35) Identify the memory
management technique which has the following weakness
(list all that apply):
30. Overhead of complex memory
management
virtual
memory, paging
virtual
memory, segmentation
31. A small amount of internal
fragmentation
simple
paging
virtual
memory, paging
32. Inefficient use of memory
due to internal fragmentation
fixed
partitioning
33. Inefficient use of processor
due to need for compaction to counter external fragmentation
dynamic
partitioning
34. There is no simple
relationship between logical addresses and physical addresses.
segmentation
35. Maximum number of active
processes is fixed.
fixed
partitioning
(36-39) Identify these terms
and hardware and OS features used in support of program relocation and paging.
36. Contains the address at
which a program is loaded.
base
register
37. Contains the address of the
last memory location allocated to the code + data.
bounds
register
38. Used to check the address of
a memory access against the bounds register.
comparator
39. The address at which a
program is loaded
base address
40. T/F: The difference between
segmentation and paging is that under segmentation the entire program is placed
into contiguous memory, while in paging this may or may not be the case.
false