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lecture15 - Caching and Intro to File Systems An old...

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Caching and IntrotoFile Systems An old Homework problem Consider a virtual memory system with 32 bit addresses and 8 KB pages. Each page table entry is 2 bytes long, and there is one leve lofpage table. The entire 32 bit address space is available to processes. Consider a process that has allocated the top and bottom 128 MB of its address space. Howmuch memory does its page table use. (Note that 1MB = 1048576 bytes) Nowconsider the same process in a twolev e lpaging system with the same size pages, but twopage identifiers of 10 and 9 bits for the first and second leve lo fthe page table. Howmuch memory does this page table consume for the same process? Answer: The first page table takes the same amount of space for all processes. 8K page tables imply that the offset takes up 13 bits, leaving 19 bits for the page identifier .There are 2 19 twobyte entries which
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lecture15 - Caching and Intro to File Systems An old...

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