CIS343|510
Chapter Seven Review w/ AnswersIdentify 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 exact physical parallels.
logical organization
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
Briefly characterize the fragmentation that is found with each of these memory management techniques. (For example, “no internal fragmentation, a small amount of external fragmentation”).
12. Fixed partitioning
internal fragmentation; no external fragmentation
13. Dynamic partitioning
no internal fragmentation; external fragmentation
14. Simple paging
no external fragmentation; a small amount of internal fragmentation
15. Simple segmentation
no internal fragmentation; some external fragmentation
16. Virtual memory paging
no external fragmentation; a small amount of internal fragmentation
17. Virtual memory segmentation
no internal fragmentation
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18. What is compaction? Why is it needed? For which memory management
techniques is it needed?
a. Moving used portions of memory up to the top to fill up the
holes left by fragmentation.
b. Because of external fragmentation.
c. Dynamic partitioning
Identify these terms related to relocation.
19. A reference to a memory location independent of the current assignment
of data to memory.
logical address
20. An address expressed as a location relative to some known point.
relative address
21. An absolute address, an actual location in main memory.
physical address
Identify these terms related to paging and segmentation.
22. The equal-size chunks that a process is divided into.
pages
23. The equal-size chunks that memory is divided into.
frames
24. The chunks that a program is divided into which are not necessarily all
of the same length.
segments
25. What is the advantage of using a page size that is a power of 2?
Logical addressing scheme is transparent to the programmer,
assembler, and linker.
Fairly easy to implement hardware function to perform dynamic
address translation at run time.