Hands-On System Programming with Linux

Addressing 1 – the simplistic flawed approach

Okay, now to the memory pyramid; even if we agree that virtual memory is now a possibility, a key and difficult hurdle to overcome remains. To explain this, note that every single process that is alive will occupy the entire available virtual address space (VAS). Thus, each process overlaps with every other process in terms of VAS. But how would this work? It wouldn't, by itself. In order for this elaborate scheme to work, the system has to somehow map every virtual address in every process to a physical address! Refer to the following mapping of virtual address to physical address:

Process P:virtual address (va) → RAM:physical address (pa)

So, the situation is something like this now:

Fig 7: ...