0 votes 0 votes in calculating emat with page fault service time given some solutions use( page fault rate(p)*page faullt service) + memory time and some use ( p*page faullt service) + ((1-p)* memory time) whats the difference? A_i_$_h asked Nov 6, 2017 A_i_$_h 493 views answer comment Share Follow See all 7 Comments See all 7 7 Comments reply abhishek tiwary commented Nov 6, 2017 reply Follow Share depend upon the question framing u get to know which formula is to be applied when and why refer previous year question both formula has to be applied 1 votes 1 votes Habibkhan commented Nov 6, 2017 reply Follow Share Post the specific questions instead @A_I_$_h.. 0 votes 0 votes Shubhanshu commented Nov 6, 2017 reply Follow Share @A_i_$_h post the question. 0 votes 0 votes joshi_nitish commented Nov 6, 2017 reply Follow Share @A_i_$_h this is because, if p<<1 (extremely less than 1)....then 1-p$\approx$1 for ex: if p=0.1, then use ( p*page faullt service) + ((1-p)* memory time), because here 1-p=0.9(you can not ignore p), but if, p=$10^{-6}$=0.000001, then use ( page fault rate(p)*page faullt service) + memory time, because here 1-p$\approx$1 0 votes 0 votes Shivam Chauhan commented Nov 6, 2017 reply Follow Share @A_i_$_h Page fault service time includes memory access time after page is replaced. (Refer to Galvin) So EMAT = [p*page faullt service time] + [(1-p)* memory time] always use this formula 0 votes 0 votes A_i_$_h commented Nov 8, 2017 reply Follow Share A demand paging system takes 100 time units to service a page fault and 300 time units to replace a dirty page. Memory access time is 1 time unit. The probability of a page fault is p. In case of a page fault, the probability of page being dirty is also p. It is observed that the average access time is 3 time units. Then the value of p is for this we use ( page fault rate(p)*page faullt service) + memory time 0 votes 0 votes A_i_$_h commented Nov 8, 2017 reply Follow Share thanks @joshi If p value is known we can decide based on it but if p value is supposed to be found then ? 0 votes 0 votes Please log in or register to add a comment.