7. Assume an architecture that uses base and limit register for memory managemen

Question

7. Assume an architecture that uses base and limit register for memory management. The memory manager uses variable sized partition allocation. The current memory allocation is as shown below.

There is a new memory request for 9 Kbytes. Can this allocation be satisfied? If not why not? What is the amount of external fragmentation represented by the above figure?

Solution:

8. What is the relationship between page size and frame size in a paged memory system?

Solution:

9. In terms of hardware resources needed (number of new processor registers and additional circuitry to generate the physical memory address given a CPU generated address) compare base and limit register solution with a paged virtual memory solution.

Solution:

10. Please answer the following question upon the figure shown in the following about page table,

1) What are the page number, and offset?

Solution:

2) What is the corresponding frame number?

Solution:

Explanation / Answer

7)

No this allocation cannot be satisifed as we don't have enough continous space to allocated 9k in the memory. Therefore we won't be able to allocate the requested 9K required by program.

External fragmentation is the amount of free chunks of space available in the memory. In this space we have 10k of space avialable in the memory. Usually the architecture should utilize the free memory chunks and should allocate them together in order to avoid separated free memory chunks.

8)

page size is generally equal to the frame size. page size is used in virtual address used by the CPU and the frame size is used in physical addresses. Both are used to find the region of memory where the access is made.

9)

In case of fixed parition we use base registers. It takes less hardware but we see the issue of internal fragmentation in this.

In case of variable partition we use both base and limit register. It requires additional hardware but the problem of internal fragmentation is solved in this type.It automatically allocates just enough memory for the processes.

10)

the page offset is 234 and page number is 003E1

the frame offset is 234 and page number is 0044

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