Software architecture characterization

A large part of Boeing Defense d Space Groups (D&SG) business is to build sojtware-intensive systems for its government customers such as the U.S. DoD and NASA. Some of these products, such as an Airborne Warning and Control System (AWACS) or an inertial Upper Stage (lUS), exist as long-lived (20+ years) product lines that are more like legacy systems under continuous maintenance than true product lines. Also, the business climate for U.S. aerospace companies over the past several years has stimulated Boeing DdWG to look for ways to reduce system development costs and improve the quality factors for the products it deiivers. Systematic reuse, with its emphasis on domains, competencies, product lines, and architectures is viewed as an enabling technology for achieving those goals. To understand and test application of these concepts, Boeing D&SG kicked off a Hardware and Software Reuse Initiative in August of 1995. As the name implies, ~heD&SG Reuse Initiative must jind ways to apply systematic reuse thattreat hardware and sojlware issues together. Part of the reason for this challenge is that the majority of products that D&SG delivers have signljicant functionality being provided via electronic, electro-optical, or electro-mechanical devices. Another part of the reason is thatD&SG emphasizes “systems thinking” during product development. The point of intersection of hardware and sojiware where systematic reuse perhaps has the greatest leverage is architecture. Therefore, an internal research and development activity under the auspices of the D&SG Reuse Initiative was kicked off in September of 1995 to spec.ijically address architecture issues. One of the jirst observations emerging from this activity was that the lack of Urrforrnip among the vars”ous D&SG groups in descriptions of architecture signt~cantly impedes exchange of technical architecture data and knowledge across groups. This paper discusses an approach to architecture description devised specifically to alleviate that problem in the hope of creating a climate for reuse of open, commercial off-the shelf (COTS) based architectures.