    AST RESEARCH, INC.         TECHNICAL BULLETIN #0697A                 08-19-91

                  SIMULATION SCIENCES SOFTWARE AND AST 486 SYSTEMS

    PROBLEM:       Systems using the 80486 microprocessor will not recognize the
                   hardware security key, causing Simulation Sciences Inc's
                   Software Process version 4.01 to stop execution.  This problem
                   exists on all manufacturers 80486 systems, including AST's
                   that have a parallel port implemented on the motherboard.

    SOLUTION:      This is not an issue that AST can resolve. However, AST
                   systems can be made to operate by disabling cache in system
                   setup.  This is a temporary work around and the customer
                   should contact Simulation Sciences Inc. at (714) 579-0412 for
                   proper corrective action.