Abstract: A database system accesses database records referenced by a binary number key having two fields, a typeID field containing only deterministic bits, and a uniqueID field permissibly containing one or more non-deterministic bits at any bit positions therein. The database system maintains a set of databases, each being identified by a separate value of the typeID field of the binary number key. The records of each database are allocated among a plurality of bins, with each bin being identified (keyed) by separate value of a binID field, and with each record being identified (keyed) by a separate value of a recID field. The database system locates a record of interest referenced by the binary number key by first selecting a particular one of the databases that is identified by the typeID field of the binary number key.

Abstract: An integrated circuit identification device (ICID) to be incorporated into an integrated circuit (IC) includes an array of electronic cells in which the magnitude of an output signal of each cell is a function of randomly occurring parametric variations which vary from cell-to-cell. The ICID also includes a circuit for measuring the output of each cell and for producing output data having a value reflecting the particular combination of measured characteristics of all of the elements of the array. When we make the number of elements in the array large enough, we insure that to a high degree of probability, the pattern of measured array cell characteristics for an ICID embedded in any one IC will be unique and distinguishable from such patterns measured by ICIDs embedded in millions of other ICs. Thus the value of the output data produced by an ICID circuit acts as a unique "fingerprint" for the IC in which it is installed, and can be used as a unique identification (ID) for that IC.

Abstract: A bi-directional buffer includes first and second unidirectional buffers connected for retransmitting signals in opposite directions between first and second buses. When an external bus driver pulls the first bus low, the first unidirectional buffer pulls the second bus low and generates a signal inhibiting the second unidirectional buffer from actively driving the first bus. When the external bus driver allows the first bus to return to the high logic level, the first unidirectional buffer temporarily supplies a high charging current to the second bus to quickly pull it up. Similarly, when an external bus driver pulls the second bus low, the second unidirectional buffer pulls the first bus low and generates a signal inhibiting the first unidirectional buffer from actively driving the second bus. When the external bus driver allows the second bus to return to the high logic level, the second buffer temporarily supplies a high charging current to the first bus to quickly pull it up.

Abstract: A field programmable interconnect device (FPID) flexibly interconnects a set of electronic components such as integrated circuits and other devices to one another. The FPID is an integrated circuit chip including a set of ports and a cross-point switch that can be programmed to logically connect any one port to any other port. Each FPID buffer port may be programmed to operate in various modes including unidirectional and bi-directional, with or without tristate control, and to operate at various input or output logic levels with adjustable pull up currents. Each FPID buffer port may also be programmed to perform various operations on buffered signals including adjustably delaying the signal, inverting it or forcing it high or low. The FPID is linked to a host computer via a bus that permits the host computer to program the FPID to make the desired connections, to select various modes of operation of buffers within the FPID and to read out data stored in the FPID.

Abstract: A bi-directional bus repeater includes two unidirectional bus repeaters connected for retransmitting signals in opposite directions between two buses. When an external bus driver pulls either bus low, one of the unidirectional bus repeaters pulls the other bus low. When the external bus driver allows the bus to rise to the high logic level, the unidirectional bus repeater temporarily supplies a high charging current to the other bus to quickly pull it up. Each unidirectional bus repeater also generates signals indicating when it is actively pulling its output bus up or down and the indicating signals inhibit one unidirectional bus repeater from actively driving its output when the other unidirectional bus repeater is actively driving its output.

Abstract: An integrated circuit identification device (ICID) to be incorporated into an integrated circuit (IC) includes an array of electronic cells in which the magnitude of an output signal of each cell is a function of randomly occurring parametric variations which vary from cell-to-cell. The ICID also includes a circuit for measuring the output of each cell and for producing output data having a value reflecting the particular combination of measured characteristics of all of the elements of the array. When we make the number of elements in the array large enough, we insure that to a high degree of probability, the pattern of measured array cell characteristics for an ICID embedded in any one IC will be unique and distinguishable from such patterns measured by ICIDs embedded in millions of other ICs. Thus the value of the output data produced by an ICID circuit acts as a unique “fingerprint” for the IC in which it is installed, and can be used as a unique identification (ID) for that IC.