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      STACKER NOTE                                         STACKER NOTE
                  ADAPTEC SCSI DISK CONTROLLER WITH STACKER
                          (Applies to Stacker  4.x)
      STAC FAX  4501 (01-31-1994)
      -----------------------------------------------------------------
                                      
      BACKGROUND
      
      This document covers the use of the Adaptec 154x SCSI controller
      and MS-DOS 6.0/6.2, or PC-DOS 6.1 with file dates 9/30/93 or
      later, with Stacker. Under certain conditions, use of an Adaptec
      controller with a Stacker drive can make it appear as though your
      disk contains no data even though the root directory is
      preserved. Your data is intact.
      
      SOLUTION
      
        - Properly install the Adaptec controller.
        - Properly configure Stacker, Smartdrv and ASPI4 DOS 6.
           
      Properly install the Adaptec controller
      
      If you are using an Adaptec 154x bus-mastering SCSI disk
      controller, be sure that Adaptec's ASPI (Advanced SCSI
      Programming Interface) manager is properly installed on your
      system.  Install the ASPI DOS managers as well to help DOS
      communicate with the SCSI host adapter more effectively and allow
      additional SCSI devices. You'll need the ASPI DOS managers also:
      
          - To support programs that use virtual memory (such as
            Microsoft Windows 3.0 and 3.1, QEMM 386 and Qualitas
            386MAX)
          - To support programs that write large amounts of data
            directly to video memory (AHA-1540, 1542, and 1640 host
            adapters only)
          - When more than two hard disk drives are already installed
          - To install a SCSI drive that is configured at a SCSI ID
            other than 0 or 1
          - To install removable media such as a CD-ROM or tape backup
            drive
           
      For example, if you are using a AHA 1542/B, or 1542/C controller,
      the following lines should be included in your CONFIG.SYS file:
      
                FILES=40
                BUFFERS=20
                DEVICE=C:\DOS\HIMEM.SYS
                DOS=HIGH,UMB
                DEVICE=C:\DOS\EMM386.EXE NOEMS
                DEVICE=C:\ADAPTEC\ASPI4DOS.SYS
      
                                    Note
   Adaptec does not recommend loading the ASPI4DOS manager high with the
   154x/B card, but that is possible with the 1542/C model. See your Adaptec
   software manual for further details regarding  proper installation of this
   and other ASPI DOS manager software.
      
      Properly configure Stacker
      
      Stacker can work with the Adaptec controller if one of the
      following is true:
                - The /EMS switch is not used in STACKER.INI
                - Use double buffering when loading Smartdrv
                - ASPI4 DOS 6 is installed.
      
       1.  To examine or edit the STACKER.INI file type ED at the Dos
           prompt. From the File menu, select STACKER.INI. When the
           file displays, look for a line with the switch /EMS. If the
           switch is present, remove it, save the file, then restart
           your computer.
       2.  Install Smartdrv double buffering in accordance with the DOS
           instructions.
       3.  Install ASPI4 DOS 6 in accordance with Adaptec's
           instructions.
      
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      Copyright 1994 Stac Electronics
