Compounds of formula are useful in treating conditions or disorders prevented by or ameliorated by histamine-3 receptor ligands. A digital model of a feature for printing is received, wherein the feature is for authentication by an external device. Shared memory between compute nodes is emulated by tunneling packetized interconnect packets between the compute nodes. The first and second passageways are in fluid communication with one another and the second body portion is movable relative to the first body portion between first and a second positions. The programming voltage may be a high voltage, above the VCC of the integrated circuit.