Increase page size Install larger hard drive Install multiple hard drive and use
ID: 3769628 • Letter: I
Question
Increase page size Install larger hard drive Install multiple hard drive and use all of them use better page replacement algorithm Lost Update p1, p2, are processes. X, y, z are common variables. Consider two processes: p1, p2. The processes access one and only one common variable x and several local variables. A, b are local variables. Will the following problem has lost update? P1 will ; Repeat 1000 time; c1 = 1; c1 = c1 + 1; x = c1; and repeat, P2 will; Repeat 1000 time; c2 = x; c2 = c2 - 1; x = c2; and repeat. P1 will; Repeat 1000 time; c2 = a; c1 = c1 + 1; a = c1; and repeat. P2 will; Repeat 1000 time; c2 = b; c2 = c2 - 1; b = c2; and repeat.Explanation / Answer
page fault is denoted by p and no page fault by n
number of frames = physical memory size / page size
the page size = frame size
Method: - if the requested page is in memory already, change its used bit as 1, otherwise, execute the following algorithm
Algorithm:
repeat until page has been stored
if scan pointer is at frame whose used bit is 0
then select it
put new page here
set used bit to 1
move scan pointer to the next frame
else
set used bit to 0
move scan pointer to the next frame (wrap around to first frame
if at the last frame)