Question

Q1. Consider the following reference string and the frame size is 3 (3 pages can be in main memory at a time) 10 2 3 4 1 2 3 0 3 2 1 4 1 1 0 3 4 1 2 Apply the following page replacement algorithms and find the page faults: a. FIFO b. Optimal LRU

Answer 1

Given reference string 102 3 4 1 2 3 0321411034 12 frame size=3 Page fault:- in the memory. pager If the & not in the memory then page it is a considered a page fault, FIFD:- It stand for first in First out. It keeps track of all queue If a in to be inserted then the oldey P page removed which in in the front of queue leta start. page fault is indicated a "p new page 3 Initially there are empty slots so of poge faulta no =3 0 2 2 2 3 3 3 0 3 - 2 2 2 3 O o 4 3 4 3 3 - 1 -- 1 4 - - - 0 3 4 0 2 4 3 2 4 4 4 4 3 11 3 1 1 1 1 total no. of page faults = initial faubta + remaining, 14 => 14 page faults.

page replacement: in the memory Optimal → It keep track of all pogen queue. pages are replaced with the page which is not uned for the longent time. let start 0 2 3 4 2 3 3 2 9 2 2 2 2 2. 2 2 2 0 0 3 4 4 4. 3 4 3 Inlo - O 1 1 1 1 1 1 1 - O 3 - 2 - - 1 4 u 4 14 6 1 4 3 4 3 2 4 3. 0 0 0 no. page faults = 11 of Least recently wied: - It keep track of all the pogen in memory pa queue. . → Pagen are replaced with the pogen leart leta start which are recently wed - 2. 3 1 2 3 O 3 2 2 2 Jauml 0 0 -Mit 3 olm 3 mld Jall 2 ↑

1 4 1 10 3 4 1 2 3 3 3 4 2 4 2 g 0 - 2 O 2 0 1 1 total no. of poge faults = 16 Finally for ELFO no. of page for optimal no. of page to LRU no. faulte 14 fault=1 fault = 16 of page