A computer has a main memory with access time $M,$ and a disk with average access time per page $D.$ The

only accesses attempted to main memory are due to cache misses. Of these, a fraction $h_t$ hit in the TLB

yielding a valid translation. Of the fraction $1-h_t$ that miss in TLB$,$ a fraction $h_m$ are present in physical

memory; the rest page fault. Assume that page table accesses always themselves take $M$ cycles as they are

always in main memory. What is the average main memory access time ignoring any software overhead?

$($Hint: Consider three cases: TLB hit; TLB miss with no page fault; TLB miss with page fault.$)$