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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