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. 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:

9. 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

Solution :
7)

Here there is total of 11KB memory free.
But free memory is divided into two fragements.
Largest fragment is of 8K and new request is for 9K.
Hence, fragment with 9K memory can not have memory allocation here.

Here, there is an external fragmentation of 2KB.

8)
Paged virtual memory solution needs a specific unit,
which will translate Logical address to the physical address.

Page virtual memory also need memory inside main memory to store page table of currently running processes.

Where as, Base limit register solution will only need to store base and limit register of each partition.
Base limit register solution also need to have one allocation table.

but, size of allocation table will be very much less than size of page tables of all processes.

hence, paged virtual solution needs more memory.

9)

Answer 1 : from virtual address, we can say that page number is : 3E1 and offset is : 234
Answer 2 : From the table , we can say that Corresponding frame number is : 0044

If you have any doubts then you can ask in comment section.

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