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      STACKER NOTE                                         STACKER NOTE
                   STACKER AND WINDOWS FOR WORKGROUPS 3.11
                 (Applies to Stacker 4.0 for Windows & DOS)
      STAC FAX  4201 (02-16-1994)
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      BACKGROUND
      
      Windows for Workgroups (WFW) 3.11  includes a new feature called
      32-bit file access, which uses a 32-bit cache that resides
      between the Windows environment and DOS. Stacker 4.0 is
      compatible with WFW 3.11, as a 16-bit device driver. Stacker 4.0
      does currently work with 32-bit file access, although as a 16-bit
      device driver. Stac is committed to taking full advantage of 32-
      bit file access, and is working to address this important issue.
      
      32-bit file Access and Disk Compression
      
      Stacker 4.0 currently addresses the issue of 32-bit file access
      by identifying compressed drives as 16-bit drives to WFW 3.11.
      This has no effect on any other drives in your system, which
      continue to use the 32-bit file access feature. Any compression
      program, including DoubleSpace, that allows 32-bit file access to
      be enabled for a compressed drive continues to interface with the
      32-bit cache as a 16-bit program. According to our measurements
      the best performance is achieved by increasing the size of
      standard caches such as SMARTDRV.
      
      Please note that 32-bit disk access is not the same thing as 32-
      bit file access. Stacker 4.0 is compatible with 32-bit disk
      access.
      
      Speed
      
      WFW 3.11's cache holds data in an uncompressed form.  The
      advantage of this approach is that it eliminates decompression
      cycles. SMARTDRV holds data in a compressed form.  The advantage
      of this approach is that the cache can hold more than twice the
      data, and disk read access is reduced. Each method has its own
      advantages, but on a compressed drive, the SMARTDRV approach
      results in improved system performance.
      
      32-bit file access typically operates with a 4 MB cache size.
      When running Stacker 4.0 you can optimize your system's
      performance by increasing the size of the SMARTDRV, or other
      third party cache to match what WFW 3.11's cache size would be.
      Enabling the SMARTDRV (or other) cache with 2 to 4 MB of RAM
      should increase your overall system performance. Note that this
      approach increases the performance of DoubleSpace drives as well.
      
      For more tips on increasing your Stacker system's performance,
      see StacFax 4509.
      
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      Copyright 1994 Stac Electronics