Page 144 - DCAP403_Operating System

Unit 7: Memory Management

Overlaying: It means replacement of a block of stored instructions or data with another. Notes

Paged Memory Management Unit (PMMU): Same as MMU.
Physical Address: An address seen by the memory unit-that is, the one loaded into the memory-
address register of the memory-is commonly referred to as a physical address.

7.15 Self Assessment

Fill in the blanks:

1. The method assumes dividing a program into self-contained object code blocks called .......
........................... .
2. The place in memory where an overlay is loaded is called a .................................. region.
3. In multiprogramming several programs run at the same time on a .................................. .
4. In .................................. memory allocation method the memory manager places a process in
the largest block of unallocated memory available.
5. To move a program from fast-access memory to a slow-access memory is known as ...........
....................... .
6. The process of translating virtual addresses into real addresses is called ............................. .
7. Belady’s Optimal Algorithm is also known as .................................. .
8. .................................. happens when a hard drive has to move its heads over the swap area
many times due to the high number of page faults.
9. The full form of FINUFO is .................................. .
10. EPROM stands for .................................. .
11. RAM stands for .................................. .
12. 1 MB equals to .................................. .

7.16 Review Questions

1. Write a short description on:
(a) Binding of Instructions and Data to Memory
(b) Memory-Management Unit
(c) CPU utilization

(d) Memory Relocation
2. What is high-speed cache?
3. What is overlaying? Explain it.
4. Consider a logical address space of eight pages of 1,024 words each, mapped onto a physical
memory of 32 frames.
5. How many bits are there in the logical address?
6. How many bits are there in the physical address?
7. Why are segmentation and paging sometimes combined into one scheme?
8. Describe a mechanism by which one segment could belong to the address space of two
different processes.

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