    AST RESEARCH, INC.          TECHNICAL BULLETIN # 1485         5-2-96

    TITLE:  Ascentia 910N, PStation, UnixWare 2.01

    SUMMARY

       When an Ascentia 910N is docked to a PowerStation III and using
       an Adaptec 1542CF SCSI adapter, UnixWare Personal Edition 2.01 may
       not install successfully.  During the installation process,
       the operating system may halt with the following error message:

       PANIC: Kernel mode address fault at user address 0X00000000.

       This issue applies to the following systems: All Ascentia 910N and
       all Power Station III systems.

    ISSUE

       When the hardware subsystems are configured together, excessive
       noise may occur on the data bus.

    BACKGROUND

       During bus master cycles, the Adaptec board assumes control of the
       ISA bus in the PowerStation III.  The Adaptec board contains an
       ASIC chip that among other functions, acts as the bus transceiver
       for the board.  The drive characteristics of the ASIC chip will
       not allow it to successfully overcome noise on the system bus,
       when transmitting data from the Adaptec board to the ASIC system
       controller in the PowerStation III.

    ACTION

       Based upon the investigation of this problem, AST has determined
       that the issue cannot be resolved.

    NOTES

       The Adaptec 1540 fails in the same manner as the 1542.
       The Adaptec 1510 does not exhibit the failure condition and is an
       acceptable alternative adapter.

    TAN # 006000RH

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