A system and method are provided for generating and detecting unique identification signatures for customer replaceable components or units for use in customer owned andor controlled image forming devices. For example, a first virtual device and a second virtual device may be configured to use the same physical port. For each group, aggregate element structures are formed from the intermediate result structures and, if the aggregate function specifies ordering, the aggregate element structures are sorted based on a sort key. The business method is invoked again based on a predefined retry policy when the retry conditions are satisfied. From superposed sub-beams, a detector system is able to generate position signals at least with respect to the movement of the object along the first and second direction of movement. The thickness of the spacer is smaller than the thickness of the first brazing filler metal before melting.