Page 60 - slides.dvi
P. 60

2.
                                                                          1.
              •
                                                              3.
                                                                                                  •
                                                                                       •
                          •
                                                       •
                                                                    if
                                                  •
                                        •
                                             •
                                                                                 Then
                                                                                                  we
                                                                                                         When
   Operating
                                                                                       add
                                                                    an
                                 Scheme
                          never
              hence
                                                                          check
                                                       find
                                                                                       its
                     process
                                             when
   Systems
                                                                                                               Demand
                                                       a
                                                                                             “invalid”
                                        restart
                                                              otherwise
                                                                                                  create
                                                  initiate
   —
                                                                                                         loading
                                                                          PTE
                                                                                             or
                                                                    invalid
                     first
              many
                          brings
                                             I/O
                                                                                 whenever
                                                                                                  its
                                                       free
                                                                                                         a
                                        the
                                                                          to
                                                  disk
                                             is
                          in
                                                                                       process
                                 described
   Demand
                                                              ‘page
                                                                                 we
              real
                          a
                                                                                                         new
                                                                                                               Paging
                                                  I/O
                                                              in’
                                                       frame
   Paged
                     begins.
                                                                                                  address
                                        process
                                                  to
                                                                    reference
                                 above
                                                       in
                          page
                                                                                       control
                                                              the
                                             finished
                                                                                 receive
   Virtual
                                        at
                                 is
                                                                          determine
                                                                    ⇒
              systems
                                                                                 a
                                                                                                         process
                                                  read
                                                                          if
                                                                                                  space
                          until
                                                                                             “non-resident”;
                                        the
                                                                                                               Details
                                                                    kill
   Memory
                                                                                       block
                                                                                                         for
                                 pure
                                                  in
                                                              desired
                                             modify
                                                       memory
                                                                                 page
                                                                                             and
                                                                                                  (e.g.
                                                  the
              explicitly
                                             the
                                                                                       (PCB)
                                        faulting
                          required
                                                                          “invalid”
                                                              page:
                                                                                 fault:
                                                                    process;
                                                                                             then
                                                                                                  page
                                 demand
                                                                                       to
                                                                          or
              load
                          ⇒
                                             PTE
                                                                                                         execution:
                                                  desired
                                                                                       the
                                                                          not
                                             for
                          get
                                                                                                  tables,
              some
                                 paging:
                                                  page
                                        instruction
                                             this
                          lots
              core
                                                                                                  etc),
                          of
                                                  into
                                             page
                                                                                                  but
                                                  the
              parts
                          page
                                             to
                                                                                       ready-queue.
              of
                                                  new
                                                                                                  mark
                                             show
                          faults
              the
                                                                                                  all
                                                  frame
                          and
                                             that
                                             it
                                                                                                  PTEs
              process
                          I/O
                                             is
                                                                                                  as
              first
                                             now
                          when
                                                                                                  either
                          the
                                             valid
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