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AST RESEARCH, INC.         TECHNICAL BULLETIN # 1157                4-26-95

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		 ASSIGNING A BOOTABLE SCSI CONTROLLER IN A MULTIPLE SCSI 
					   CONTROLLER ENVIRONMENT

PROBLEM

When installing a DPT PM3224 SCSI controller on Manhattan P & V servers 
with the onboard NCR SCSI controller(s) enabled, the primary/bootable 
controller will be the DPT controller.


CAUSE

PCI 2.0 specifies that the BIOSes load in order, beginning with the largest 
BIOS and ending with the smallest BIOS.

For instance, if the onboard NCR SCSI controller BIOS uses an address space 
of 16KB, and an add-in SCSI controller BIOS uses an address space of 32KB, 
the add-in controller will become the primary/bootable controller.


SYSTEMS AFFECTED
AST PART NUMBER AND DESCRIPTION

All Manhattan P and V systems.


SOLUTION

Currently, the Manhattan P & V systems DO NOT support the option of 
allowing the user to manipulate the default settings for Primary and Secondary 
controller assignments.

AST is currently negotiating with vendors for a BIOS that supports the PCI 2.1 
specification which allows the user to manipulate the load order of BIOSes.