ECS 154A Lecture Notes - Lecture 21: Logical Address, Demand Paging, Base Address
2 Aug 2016
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Lectures 21: operating system memory management: in a uniprogramming system, memory is divided between the resident monitor and the user program. Cpu is idle much of the time as the user program waits for i/o, the overhead of changing programs makes that impractical: in a multiprogramming system the memory is dynamically allocated to the os, and the multiple processes. Instructions contain only logical addresses: a processor convert from logical addresses to physical addresses by adding the process" base address to the logical address using transparent hardware. Pages are always in sizes of powers of 2, so that address bits can be easily constructed: a given process can have one or more of its pages stored in ram at any given time. The os maintains a page table for each process: a processor does the conversion from logical address to physical address relying on a page tables supplied by the.
