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Unformatted text preview: 1 CSC 4103 - Operating Systems Fall 2009 Tevfik Ko ! ar Louisiana State University October 27 th , 2009 Lecture - XVII Main Memory 2 Roadmap • Paging – Address Translation Scheme – Shared Pages • Segmentation – Address Translation Scheme – Shared Segments 16 Paging - noncontiguous • Physical address space of a process can be noncontiguous • Divide physical memory into fixed-sized blocks called frames (size is power of 2, between 512 bytes and 8192 bytes) • Divide logical memory into blocks of same size called pages . • Keep track of all free frames • To run a program of size n pages, need to find n free frames and load program • Set up a page table to translate logical to physical 17 Address Translation Scheme • Address generated by CPU is divided into: – Page number (p) – used as an index into a page table which contains base address of each page in physical memory – Page offset (d) – combined with base address to define the physical memory address that is sent to the memory unit 18 Address Translation Architecture 19 Paging Example 20...
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This note was uploaded on 10/01/2011 for the course CSC 4103 taught by Professor Ullmer,b during the Fall '08 term at LSU.
- Fall '08
- Operating Systems