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AST RESEARCH, INC.         TECHNICAL BULLETIN # 0871B                4-4-95

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			   AST COMPUTERS BANYAN ICA PLUS & BANYAN VINES


PROBLEM

When 16 megabytes (or more) of memory is installed in an AST computer system, 
a Banyan Vines ICA Plus adapter card is not functional.  


CAUSE

The Banyan Vines ICA Plus adapter card requires 128k of contiguous memory 
space to be mapped out of system memory for each adapter installed.  If two 
adapter cards are installed in a computer, the mapping for the first card 
usually takes place in 512k-640k region and the mapping for the second card 
usually takes place in the 15-16 megabyte memory region.  If RAM is installed 
in the 15-16 megabyte region, a conflict will exist between RAM and the ICA 
Plus adapter card.


BACKGROUND

This problem is usually experienced when a computer system containing two ICA 
Plus adapter cards and 8 megabytes of RAM has been operating without any 
problems.  Then the owner of the computer system decides to increase the 
amount of RAM to 16 megabytes.  Once the computer contains 16 megabytes of 
RAM, a conflict will exist and a adapter card will loose its functionality.


NOTE

The ability to set 512K of base memory is not available in the Manhattan P or 
V systems, but it is available in the older systems: Premium SE, Premium TE, 
Premmia SE, and SMP.


SYSTEMS AFFECTED

All AST computer systems except Manhattan SMP.


SOLUTION

Several possible solutions exist to resolve this problem.

1.  Use less than 16 megabytes of memory.  AST has successfully tested the 
configuration with 8 megabytes of memory.

2.  Disable the 15th megabyte region of memory.  This is a advanced setup 
feature and currently is only supported on AST's Manhattan SMP computer.

3.  Use Banyan's Memory Reduced ICA adapter card.  The ICA-RM adapter card 
only requires 16k of contiguous memory space to be mapped out of system memory 
for each adapter installed.  Additionally, the card can be mapped anywhere in 
the Shared Memory Region (640k-1MB).  Support for the Memory Reduced ICA 
adapter card began with release 5.54(5) of the Banyan Vines operating system.  
Banyan Product Notice 430 provides details on the ICA-RM adapter card.