Every process sees its own address space. The MMU translates each virtual address to a physical one through page tables, and a TLB caches the recent translations so most accesses never walk the tables.

With a TLB hit rate \(h\), a TLB lookup time \(t\) and a memory access time \(m\), the effective access time for a two level table is

\[ T = h(t + m) + (1 - h)(t + 3m) \]

which is why the hit rate matters so much more than the lookup time. See also the eigenvalue tree for how trees in other courses are linked the same way.