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STACKER NOTE                                                   STACKER NOTE
Title: Stacker 2.0 Memory Requirements.
STAC FAX Index #2503 - 2/20/92                           
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Background.

   The Stacker device driver, STACKER.COM , requires a modest amount of
   resident conventional memory.  The resident size of the Stacker device
   driver depends on the Stacker product being used, and on the way Stacker 
   is configured.  During the initialization phase, as it is loading and 
   mounting the Stacker drives, it requires slightly more memory than when 
   resident.

   Refer to the following tables to determine how much memory the Stacker 
   device driver requires.  These numbers should be used as guidelines.  Once 
   Stacker is installed, observe the STACKER.COM display as the system starts 
   to see the exact amount of memory the driver is using.


Stacker 2.0.

   This table represents memory required for each Stacker product with a
   single Stacker drive using 8k clusters.  It also shows the requirements
   on a system where Stacker is using EMS memory.  When Stacker is
   configured to use available EMS memory, it will use 64k of EMS for its
   cache and buffers.

       Product                With EMS              Without EMS
                         (Resident/(Initial))   (Resident/(Initial))
    
    2.0 Software            26K/(40K)               41K/(47K)
    AT/16, MC/16, XT/8      14K/(40K)               30K/(41K)


Additional Stacker Drives.

   If using more than one Stacker drive, the device driver will consume
   slightly more memory to map each additional drive.

       Product                With EMS              Without EMS
         
         All                    1.2K                    3 K


4K vs. 8K Clusters.

   A default cluster size of 8k offers better compression than 4k . However, 
   the device memory required to achieve the better compression is slightly 
   greater than the 4k option.  With 4k clusters, the base driver size is 
   reduced by the amount in the table below.
                                  
                                  Driver Size Reduced By
       
       Product                With EMS             Without EMS
     
     2.0 Software                4K                     8K
    AT/16, MC/16, XT/8                                  4K

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Copyright 1993, Stac Electronics                    
