CSC369H1 Final: csc369 cheating sheet
Document Summary
Memory management goal: 1, ef ciency, 2, transparency; 3, protection & sharing. 1, ef ciency: make use of memory wisely. (some portion are in dram, some portions are on disk, transfer data back and forth as needed) 2, transparency: data move back and forth between ram and disk. (give each process its own view of memory, large contiguous address space, starting at address 0. Decouple the data layout from where the data is actually stored in physical memory) 3, protection & sharing: process co-exist memory, should not access other process" memory, so we need access right(r/w/x). for vm, address spaces are per-process completely isolated. Fixed partitioning: each process gets a xed partition to use, divide physical memory into 8m regions, os occupied a separate partition, each process is granted one of these. Problems: 1, if process is smaller than partitions, wast memory (internal fragmentation); 2, if program needs more memory than partition size, overlays.
