Page 50 - slides.dvi
P. 50

8
               8
                      4
                                                  4
                                    4
                                           8
   Operating
                                    no
                                           OS
                             but
                                                                                                               Paging
                      clear
   Systems
                             get
   —
                                                  memory
                                           must
               additional
                                                                                                               Pros
                                    external
   Paging
                                           keep
                      separation
                                                                                                               and
                             internal
                                                  allocation
               overhead
                                           page
               on
                                                                                                               Cons
                      between
                                           table
                                                                                               Page 1
                                                                                                  Page 0
                                                                                           Page 2
                                                                                     Page 4
                                                                                        Page 3
                                                  easier.
                                    fragmentation
                                                             Page n-1
                                                                                                      Virtual Memory
                                           per
                      user
                                    (in
               context
                             fragmentation.
                      and
                                                                                 1
                                                                               1
                                                                                        1
                                                                                   0
                                                                                     1
                                                                       0
                                           process
                                    physical
                                                                                        4
                                                                                     6
                                                                                 2
                                                                               1
               switching
                      system
                      view
                                    memory
                      of
                                    at
                                                                                         Page 4
                                                                                      Page 3
                                                                               Page 0
                                                                        Page 1
                                                                                                Physical Memory
                                    least).
                                                                                             0
                                                                     7
                                                                  8
                                                                               4
                                                                                   3
                                                                                      2
                                                                        6
                                                                                         1
                                                                            5
                      memory
                      usage.





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