Mam,all that i know but please have a look at this :)
"
Virtual memory involves the separation of logical memory as perceived
by users from physical memory. This separation allows an extremely large
virtual memory to be provided for programmers when only a smaller physical
memory is available (Figure 9.1). Virtual memory makes the task of programming
much easier, because the programmer no longer needs to worry about
the amount of physical memory available; she can concentrate instead on the
problem to be programmed.
" ---From Galvin
what does this mean then