[12/02/2011]

FINAL EXAM IS THURSDAY 12/15 from 3:00-6:00pm.

CONFLICT FINAL EXAM IS WEDNESDAY 12/14 from 1:00-4:00pm.
-- You must email me to take the conflict exam
-- Email must be received by Friday 12/2 (today!)

Project #2 is due Friday 12/9 by 11:59pm

==============================================================

Project #2
-- If you run through all characters A-Z...a-z,
   then consider that an OUT-OF-MEMORY situation
   and exit.  Or better yet, call it a PROCESS-LIMIT
   error and simply exit the simulation.

-- If the user enters invalid input, ignore it and re-prompt.

==============================================================

Virtual memory overcomes inherent problems in contiguous and
 noncontiguous memory allocation schemes, as well as problem
  of loading ENTIRE process into memory

-- applicable to both paging and segmentation

-- virtual memory address must be translated to a physical
    memory address and, if necessary, the "missing" page or
     segment has to be loaded in from disk

==============================================================

FIFO:
   Page reference stream:
   1 2 3 2 1 5 2 1 6 2 5 6 3 1 3 6 1 2 4 3
 --------------------------------------------
   1 1 1 1 1 1 1 1 2 2 2 2 2 3 3 3 3 5 6 1
   - 2 2 2 2 2 2 2 3 3 3 3 3 5 5 5 5 6 1 2
   - - 3 3 3 3 3 3 5 5 5 5 5 6 6 6 6 1 2 4
   - - - - - 5 5 5 6 6 6 6 6 1 1 1 1 2 4 3
   * * *     *     *         *       * * * ===> 9 page faults

 


FIFO (3-frame mem):
   Page reference stream:
  1 2 3 4 1 2 5 1 2 3 4 5
 --------------------------
  1 1 1 2 3 4 1 1 1 2 5 5
  - 2 2 3 4 1 2 2 2 5 3 3
  - - 3 4 1 2 5 5 5 3 4 4
  * * * * * * *     * *   ===> 9 page faults
 
 

FIFO (4-frame mem):
   Page reference stream:
  1 2 3 4 1 2 5 1 2 3 4 5
 --------------------------
  1 1 1 1 1 1 2 3 4 5 1 2
  - 2 2 2 2 2 3 4 5 1 2 3
  - - 3 3 3 3 4 5 1 2 3 4
  - - - 4 4 4 5 1 2 3 4 5
  * * * *     * * * * * * ===> 10 page faults

 

 
  /abc/def/B2

  /abc/A1

  cd def
  cd ../def/B1

 


   ls
   B2 -> /abc/def/B2

   A hard link cannot span filesystems (e.g. NFS)
   A symlink can



Last slide
-- Given a cluster/block is 4K, what is the maximum file size
    using 1 inode (12 blocks)?
-- using single indirect?
-- using double indirect?
-- using triple indirect?