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Then the CPU also maintains the page table?

direprobs
– direprobs

2017-07-04 20:23:25 +00:00
Commented Jul 4, 2017 at 20:23
Yes, as always. Paging is not only used for swap. It also used for security (W^X/DEP etc). Simply disabling swap does not disable virtual memory.

user996142
– user996142

2017-07-04 20:30:59 +00:00
Commented Jul 4, 2017 at 20:30
That's to say there would be no virtual pages and processes have only page frames in physical memory. Because there's nothing stored at disk. However, those processes are still given virtual addresses. I'm not sure if I got this right. So to some process they could have page frames without having pages?

direprobs
– direprobs

2017-07-04 21:02:36 +00:00
Commented Jul 4, 2017 at 21:02
4

The term virtual memory does not primarily refer to the fact that pages don't have mappings to physical pages, swapping to backing storage is just a secondary mechanism. The term virtual in this context is related to that each process is presented with its own address space starting from address zero, that is decoupled from the physical address space. This is why it is called virtual. The MMU handles the mapping between virtual and physical addresses, but the operating system maintains a separate mapping for each proecss, and switches the active mapping when scheduling processes.

Johan Myréen
– Johan Myréen

2017-07-05 13:17:40 +00:00
Commented Jul 5, 2017 at 13:17

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