Control Channel Toolkit: A Software Product Line Case Study
6 Early Benefits from CCT
The CCT story continues to unfold; user systems are still in development and the CCT sustainment processes are still relatively immature. Nonetheless there are early benefits to herald. First and foremost, CCT is a ground-breaking effort within its government communities. It broke down organizational and cultural barriers to garner support for a product line approach, and it achieved its objectives. CCT was completed on schedule and within budget in December 1999 with no outstanding risks and no outstanding actions. Few software efforts in its class can boast such a track record. Moreover, CCT is being used successfully to build the Spacecraft C2 System.
The initial NRO business case for pursuing a product line approach sought benefits in several areas. These included:
This business case attempted to quantify cost savings over a ten-year life cycle, including CCT development, use, and sustainment. The NRO determined that costs during the period of intense CCT development (1997-
2000) would be higher than normal, in spite of near concurrent use with the Spacecraft C2 System. However, when forecasting was done over the longer term (1997-
2009), it was determined that overall cost savings would accrue for systems using CCT as follows:
Development 18.2% savings in anticipated total government development-related expenditures Sustainment 27.8% savings in anticipated total government sustainment-related expenditures Savings in both cases are in comparison with expected costs using a non-product line approach.
The Department of Defense has already enjoyed specific, measurable benefits in the initial use of CCT on an actual operational system¾
namely, Spacecraft C2. Because of CCT, the Spacecraft C2 Program is enjoying
reductions in development costs, schedules, work force, and product risk, as well as increased product flexibility. Table 3 summarizes these benefits.
Table 3: Summary of Measurable Benefits Attributed to Use of CCT
Factor Benefits to Spacecraft C2 System Quality One-tenth the typical number of discrepancy (defect) reports for a system of this type. The problems identified were all local ones, with localized fixes, having no ripple effects, and no effect on the architecture. Performance Use of CCT improved performance over results predicted without CCT. In identified places where reuse may lead to timing problems, CCT variation points can be exercised to apply mechanisms that circumvent CCT software and apply faster algorithms. Integration time Incremental builds completed in weeks rather than months, as was the case for non-CCT portion. This approach is a direct carryover from the incremental approach to development. Code volume The number of design objects for subsystems using CCT is lower than planned by 34% to 88% with similar reduction in actual source code size. Total SLOC developed by Spacecraft C2 is 76% less than planned. Productivity Smaller development staff required (15 versus 100 for other similar systems)
Overall costs cut by 50%
Overall schedule cut by 50%
Documented flexibility in meeting requests for modifications by the Spacecraft C2 System customer
CCT treated like a COTS product (initial training required, then development proceeded on the basis of domain specification, interface definitions, and Reuse Guide) Interviews with the Spacecraft C2 developers also revealed other, less
tangible benefits. Program staff attrition is unusually low, at two staff
members in three years. After initial training, these developers were very
satisfied with the CCT approach and praised the selection of and support for
the variation points. They reported greater professional satisfaction with the
product line approach. They expressed a sense that the pedestrian tasks had
already been done and the focus was on the interesting, mission-specific
capabilities. The risks of system failure were felt to be fewer, and the
tension on the program to be substantially lower.
The government and Raytheon have achieved the intended benefits from CCT. Spacecraft C2 has achieved measurable benefits, and there are other users beyond Spacecraft C2. The government has already met three of its first four goals: reduced development costs, increased quality, and decreased time-to-field. It is too soon to calculate the savings in sustainment costs.
Raytheon is also capitalizing on the CCT experience by using the CCT assets in its other systems and by using the CCT processes and tools on other efforts.
Other commercial organizations will have access to CCT products and may use similar approaches for launching their own product lines in spacecraft command and control. The Software Object Technology Group, a joint government and industry group led by NASA and the NRO, has applied the CCT architectural concepts to the definition of an object/interface standard for space-related applications.
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