CPSC 313 Lecture Notes - Lecture 15: National Research Universal Reactor, Working Set, Memory Management Unit
5 Jun 2016
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Consider call to open(): does so preliminary setup transfers: execution control -> os kernel while switching the cpu to supervisor mode. Kernel accesses disk to read inode for le. No user program should be able to access disk directly mem locations used to access devices should only be available in sup mode kernel stores information about the le in an object (only accessible by the kernel) Pages can be: cached: page is in physical memory uncached: on disk but not in memory unallocated: non-existent. Don"t allocate a page until you know you"re going to need it!!! Most likely programming error ie using an uninitialized or null pointer. The os will: terminate process copy contents of process" memory (memory dump?) No, core dump (oh, unix be old as shit. ) Access a page not in physical memory (major page fault) Figure out where to store page in physical memory.
