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AST RESEARCH, INC.        TECHNICAL BULLETIN # 1097                  3-9-95

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			 PREMMIA LX P/60 HANGS WITH PCI NETWORK CARDS


PROBLEM

The Racal Interlan PCI T2 board and an Adaptec 2940 rev. F board can not 
successfully share an interrupt.  When the Racal board's network software is 
invoked, the Premmia LX motherboard hangs with the following error message:

	System Overflow
	System Halted

CAUSE

The problem occurs well before the Racal board ever issues its own interrupt.  
Normal SCSI operation is "broken" once the Racal software is loaded.  A simple 
"dir" command on the SCSI drive will invoke the problem.  

The Racal software is loaded and takes over the initial handling of the 
interrupt. If the interrupt is not intended for the Racal board, a clean 
transfer to the SCSI interrupt handler should occur.  The Racal board 
determines if the interrupt is intended for the Racal board by performing 
reads to it's own register.  The Racal interrupt handler does not perform 
these reads.  The Racal interrupt also issues an "end of interrupt" command 
very early.  This "end of interrupt" command comes before the PCI interrupt 
is cleared.  

Because the PCI interrupt is level-sensitive, an additional interrupt will 
occur immediately following the "end of interrupt" command.  Additional 
interrupts follow, causing the stack overflow. 

SYSTEMS AFFECTED
AST PART NUMBER AND DESCRIPTION

501288-011     PREMMIA LX P60/3 8MB

SOLUTION

Download the software driver from Racal Interlan's BBS (508) 264-4345.  
The file name is PCODIDOS.EXE, and it is located in the ILANPCI library.