this regard each block in the flowchart may represent a module segment or portion of code which comprises one or more executable instructions for implementing the specified logical function s it should also be noted that in some alternative implementations the functions noted in the blocks might occur out of the order depicted in the figures for example two blocks shown in succession may in fact be executed substantially concurrently it will also be noted that each block of flowchart illustration can be implemented by special purpose hardware based systems that perform the specified functions or acts or combinations of special purpose hardware and computer instructions some of the functional components described in this specification have been labeled as systems or units in order to more particularly emphasize their implementation independence for example a system or unit may be implemented as a hardware circuit comprising custom vlsi circuits or gate arrays off the shelf semiconductors such as logic chips transistors or other discrete components a system or unit may also be implemented in programmable hardware devices such as field programmable gate arrays programmable array logic programmable logic devices or the like a system or unit may also be implemented in software for execution by various types of processors a system or unit or component of executable code may for instance comprise one or more physical or logical blocks of computer instructions which may for instance be organized as an.