2. [Total: 25%] In this task, we deal with virtual memory and related topics. Assume you...

 

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2. [Total: 25%] In this task, we deal with virtual memory and related topics. Assume you work on an embedded system that provides a hardware MMU. The memory page size is 4 KB, and there are in total at most 8 pages. The system only uses one level of paging, i.e., there is a single page table. The given device has 16 KB of physical memory, and 1 MB of permanent Flash storage. (a) Briefly explain the concept of virtual memory, and the role it plays in providing process isolation (max. 3 sentences). [5%] (b) How many bits does a virtual memory address have in the given scenario? Which bits are used to index the page table, and which bits for the byte offset within a page? [5%] (c) How many bits does a physical memory address have? Explain your answer. [3%] (d) The contents of the page table of a process (all addresses in hex) are as follows: page number page base address 0 Ox1000 1 0x3000 2 not mapped 3 not mapped 4 not mapped 5 0x0000 not mapped 0x2000 6 7 Resolve the virtual address 0x78CD to a physical memory address. Briefly explain the process. [7%] (e) Is the available memory sufficient to store the complete addressable virtual memory? If not, how could the limitation in physical memory be overcome? [5%] 2. [Total: 25%] In this task, we deal with virtual memory and related topics. Assume you work on an embedded system that provides a hardware MMU. The memory page size is 4 KB, and there are in total at most 8 pages. The system only uses one level of paging, i.e., there is a single page table. The given device has 16 KB of physical memory, and 1 MB of permanent Flash storage. (a) Briefly explain the concept of virtual memory, and the role it plays in providing process isolation (max. 3 sentences). [5%] (b) How many bits does a virtual memory address have in the given scenario? Which bits are used to index the page table, and which bits for the byte offset within a page? [5%] (c) How many bits does a physical memory address have? Explain your answer. [3%] (d) The contents of the page table of a process (all addresses in hex) are as follows: page number page base address 0 Ox1000 1 0x3000 2 not mapped 3 not mapped 4 not mapped 5 0x0000 not mapped 0x2000 6 7 Resolve the virtual address 0x78CD to a physical memory address. Briefly explain the process. [7%] (e) Is the available memory sufficient to store the complete addressable virtual memory? If not, how could the limitation in physical memory be overcome? [5%]