Problem Trends Why Hard? Syllabus Large discrete state spaces Continuous vs discrete math acks repetitive structure found in computer circuitry Cannot test exhaustively Intangibility Invisible interfaces Hard to experiment with and manage Transient hardware faults vs. software errors Hard to diagnose problems Copyright ncy Leveson, Sept 1999�� �� ������������������������ Problem Trends Why Hard? Slyllabus � Other Factors � � � � � � � � � � � � � � � � � � � � � � � �� �� �� �� �� �� �� �� �� �� �� �� �� �� �� �� �� �� �� �� �� �� �� �� Large discrete state spaces Continuous vs. discrete math Lacks repetitive structure found in computer circuitry Cannot test exhaustively Intangibility � � Invisible interfaces Hard to experiment with and manage Transient hardware faults vs. software errors � � Hard to diagnose problems Copyright c Nancy Leveson, Sept. 1999 �