Given Page requests: Reference string:$1,1,2,1,1,3,1,4,3,2,4,2$

Draw the memory allocation states as the above pages are being referenced for the given scheduling algorithm $($given the respective number of page frames$).$ What is the number of page faults for each algorithm $?$

$1.$LRU

Assume there are $3$ page frames of physical memory

$2.$

NFU $/$ LFU

Assume there are $3$ page frames of physical memory

There can be situation$/$s where more than one page can be evicted. In that case: use LRU to determine which page gets evicted.

$3.$

AGING

Assume there are $3$ page frames of physical memory

Also assume there are $4$ bits in the counter for each page

$4.$

NFU is a page replacement algorithm. But it has a major problem. What is it $?$ Explain.

$6.$

Which algorithm is the most efficient algorithm that approximates LRU well $?$