Architectural Description Language = Module (Inter)Connection Language? In my previous posting, I noted that "one can view the design as embedded not only in the circuit board, but also in the connectors embedded in the chips themselves." It is difficult to express this distinction between the concrete circuit board with specific chips embedded on it and an electronics kit containing a breadboard with a box of chips. Certainly the circuit board is a concrete, fully realized, architecture, whereas the "kit" is some form of abstract architecture. The kit cannot be used to design or build anything; it can only be used to realize a range of possible designs. The set of possibilities is determined to a large degree by the modular interfaces of the electronic components.
It turns out that others have noticed the connection between an architecture and connection or interconnection. Just try "module (mil OR mcl) adl language (connection OR interconnection)" as a Google search term. It appears that some of the literature considers a MIL (module interconnection language) to be simply an older term for ADL (Architectural Description Language). In any case, it seems clear that connections, interfaces, interconnections, interoperability, are all core concerns of architecture. I'll go further and claim that composition is the essence of architecture, and thus the design of interfaces among the composed components (be they objects or processes) is the essence of architecture.
Thus, the essence of the LEGO architecture is the stud-and-tube coupling system, which was patented in 1958. In fact, LEGO was originally (1955) described as the "LEGO System of Play." Not an individual toy, but a system for making toys. The original name for a LEGO brick was "Automatic Binding Brick." (Note the use of the term "binding" outside the realm of computer languages.) What do I mean by the essence of architecture? I mean something along the lines of the definition of architecture given in IEEE Std 1471 Recommended Practice for Architectural Description of Software-Intensive Systems:
Architecture: The fundamental organization of a system embodied in its components, their relationships to each other and to the environment and the principles guiding its design and evolution.
Of course, this begs the question, what is the fundamental organization of a system? This is where the term architecture gets overloaded. If I buy a LEGO kit for a Star Wars object, say the Millennium Falcon (MF), when it is finished, it has an architecture. Thus, what should we call the (1) kit, (2) the blueprint for building the MF, (3) the set of all possible LEGO Bricks, (4) the coupling system? LEGO calls (3) the "System of Play". I lean towards calling it the LEGO Modular Architectural Framework (MAF). I'd then call (4) the LEGO (Brick) Module Architecture (MA). That leaves (2), which I'd call the LEGO MF Architectural Blueprint.
Let's apply this to the electronics kit. The kit would still be the kit. The schematic for the kit would be the Architectural Blueprint. The result of using a blueprint would be an actual electronic application, say a radio, that has an Architecture. The bread board and all the chips I can use with it is the MAF. The chip and breadboard connectors would be the MA. Note how each of these architectures can evolve. I can evolve the radio without changing the MAF or the MA, say add a noise filter chip from the kit. I can evolve the MAF w/o changing the MA, say adding new types of components or changing the function of existing components. Or I can change the MA, which that new components may not work with old components.
4:05:16 PM 
