| 摘要 |
An access control module restricts access to a computer system to authorized users and selectively controls each user's access to associated computer peripherals such as data storage units, printers, and communications equipment. During start-up of the computer system, a microprocessor associated with the module invokes a software routine that requests entry of a valid user identification code. In response to the code, the microprocessor retrieves from a main non-volatile storage unit pre-recorded information regarding the user's authority to access each of the peripherals, and loads the information into a secondary storage unit comprising random access memory and an address decoder adapted to retrieve data therefrom. Thereafter, the address decoder responds to each peripheral address signal generated in the input/output channel associated with the computer system and retrieves from the secondary storage unit the access information relating to the peripheral identified by the address signal. A latching circuit generates and maintains a signal indicating a violation of computer security if the retrieved information indicates that the current user of the computer system is not authorized to access the selected peripheral. The microprocessor responds to the signal indicating security violation by applying signals to the input/output channel which interrupt the operation of the computer system and interfere with access to the selected peripheral.
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