Systems and methods of fault detection in a Unix environment. The invention also relates to use of PBI based polymeric forms of ionic liquids and their membranes for gas sorption, permeation and separation. The translation rules, mapping rules, and other information may be used by the integration bridge during a mapping process to control communication between components. Several graph metrics are calculated and applied to the clone dependency graph to estimate the impact of changing a source file on other source files of the software. A light detector is operable to detect light reflected by the marks or light passing through a plurality of regions each of which is defined between adjacent ones of the marks. The tag dispenser is then actuated to dispense the next printed tag.