can someone help me with this question? A process references five pages, A, B, C

Question

can someone help me with this question?

A process references five pages, A, B, C, D, and E, in the following order:

A; B; C; D; A; B; E; A; B; C; D; E

Assume that the replacement algorithm is first-in-first-out

(a) Find the number of page transfers during this sequence of references starting with an empty main memory with three page frames. Present all your explanations and details

b) Find the number of page transfers during this sequence of references starting with an empty main memory with four page frames. Present all your explanations and details.

Explanation / Answer

• There are quite a few trade-offs of small versus large page sizes:

• Small pages waste less memory due to internal fragmentation.

• Large pages require smaller page tables.

• For disk access, the latency and seek times greatly outweigh the actual data transfer times. This makes it much faster to transfer one large page of data than two or more smaller pages containing the same amount of data.

• Smaller pages match locality better, because we are not bringing in data that is not really needed.

• Small pages generate more page faults, with attending overhead.

• The physical hardware may also play a part in determining page size.

• It is hard to determine an "optimal" page size for any given system. Current norms range from 4K to 4M, and tend towards larger page sizes as time passes.

Main Memory frames: Page transfer count

A 1

B A 2

C B A 3

D C B 4

A D C 5

B A D 6

E B A 7

E B A 7

E B A 7

C E B 8

D C E 9

D C E 9

9 page transfers.

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