Unformatted text preview: ington Virtual Address Mapping Physical
Memory A virtual address can be
mapped to either
physical memory or disk.
Disk IndirecMon University of Washington A System Using Physical Addressing CPU Physical address (PA) ... Main memory 0: 1: 2: 3: 4: 5: 6: 7: 8: M-‐1: Data word ¢ Used in “simple” systems like embedded microcontrollers in devices like cars, elevators, and digital picture frames IndirecMon University of Washington A System Using Virtual Addressing CPU Chip CPU Virtual address (VA) MMU Physical address (PA) ... Main memory 0: 1: 2: 3: 4: 5: 6: 7: 8: M-‐1: Data word ¢
¢ Used in all modern desktops, laptops, servers One of the great ideas in computer science IndirecMon University of Washington Virtual Memory (VM) ¢
¢ Overview and moMvaMon IndirecMon VM as a tool for caching Memory management/protecMon and address translaMon Virtual memory example Virtual Memory as Cache University of Washington VM and the Memory Hierarchy ¢ ¢ Think of virtual memory as an array of N = 2n conMguous bytes stored on a disk Then physical main memory (DRAM) is used as a cache for the virtual memory array § The cache blocks are called pages (size is P = 2p bytes) Virtual memory VP 0 Unallocated VP 1 Cached Physical memory 0 Uncached Unallocated Cached Uncached Cached VP 2n-‐p-‐1 Uncached N-‐1 Virtual pages (VPs) stored on disk 0 Empty PP 0 PP 1 Empty Empty M-‐1 PP 2m-‐p-‐1 Physical pages (PPs) c...
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- Fall '09
- Virtual memory, University of, Virtual Memory