Virtual Memory and Address Translation

Virtual Memory andAddress Translation1 ReviewProgram addresses are Virtual addresses. Relative offset of program regions can not change during program execution. , heap can not move further from Virtual addresses == physical Address inconvenient. Program location is compiled into the single offset register allows the OS to place a process Virtual Address space anywhere in physical Memory . Virtual Address space must be smaller than physical. Program is swapped out of old location and swapped into creates external fragmentation and requires large 2ggqgregions of contiguous physical Memory . We look to fixed sized units, Memory pages, to solve the MemoryConceptKey problem: How can one support programs that require more Memory than is physically available? How can we support programs that do not use all of their Memory at once?

address space. Address translation is ¾A. Frequent 9 ¾B. Infrequent Changing address mappings is ¾A. Frequent ¾B. Infrequent Paging Virtual address translation A page table maps virtual pages to physical frames (f,o) Program P CPU P’s Virtual Address Space Physical 20 910 1 Memory po 16 910 1 fo Virtual Add 10 Page Table (p,o) p Physical ...

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  Memory, Virtual, Translation, Address, Virtual memory and address translation, Address translation

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