- Virtual address bits are decided by ISA (Instruction Set Architecture), and P address bits are based on RAM available. In the cases considered here, there is 32-bit ISA and 256MB RAM.
- Page offsets depend upon frame/page size. Here each page has a size of 4KB.
- This is how an address in RAM is translated.
- When T. address (Page) is on Disk.
- In this case, CPU generates an exception: Page Fault
- Hardware gives control to OS’s Page Fault Exception handler.
- OS decides which page to move out from RAM to replace with this recently accessed one.
- If the page is dirty, it has to be written on the disk too.[ The bit indicates that its associated block of memory has been modified and has not yet been saved to storage. ], then update page table. Now OS jumps to the same instruction what caused fault.
- Page Faults are very expensive.