Abstract: An expandable system such as a computer system includes a plurality of stacked functional modules with each module engaging an abutting module in a physically locked relationship. Electric power for the modular system is provided to all modules through power lines within each module housing for EMI shielding with abutting modules having mating electric power connectors.

Abstract: An access control mechanism for granting, revoking, and denying authorization to computer system objects using a customer supplied set of verbs, parameters, attributes, and functions. The access control mechanism employs a processor for providing access controls to objects comprising subject memory, verb memory, object memory, definition memory, rule memory and an evaluator. The processor may be embodied as a microprocessor and memory, or a computer using software. The subject memory stores specified user attributes in a matrix having information for each user on each row, with user attributes in each field. The object memory stores object names, object attributes, and rules for defined verb names. The definition memory stores field definitions, external function declarations and strings. The rule memory stores rule names with their associated boolean expressions.