A Technical History of the SEI

Diverse experience in industry suggests that this type of development is almost always accomplished
on the basis of early commitment to effective architectural structures. There are two principal
reasons for this. First, architectural structures have enormous influence on quality and security
outcomes for systems. Without early consideration of quality and security attributes, it may be
infeasible to “bolt them on” later in a process. Indeed, for many categories of systems, early architectural
decisions can be a greater influence on success than nearly any other factor. Second, architectural
structures strongly influence the work breakdown structure for major software-intensive
systems. The ability to achieve an effective granularity of effort—breaking larger tasks into
feasible subtasks that can be managed separately and at differing tempos—is an architecturebased
outcome at nearly every level of scale.
It is easy to see the benefits of the “framework-and-apps” model ubiquitously adopted in the commercial
sector for mobile devices, web applications, GUI development, and other categories of
systems. This model is a compelling example of architecture-enabled scale-up. At the SEI, we aspire
to that same approach in defense software: for example, in the development of principles of
design for systems of systems. Military leaders have described a shift from platform-focused approaches
to payload-focused approaches. This shift—which is premised on improving agility
while lowering costs and risks—is enabled by appropriate architectural concepts.
While many areas of technical development are needed to aggressively advance this vision, it is
nonetheless possible in many domains to advance development approaches based on these concepts.
The evidence of this feasibility is the widespread adoption of architecture-led approaches in
the commercial sector for products, software as a service (SAAS) services, and the like. Indeed,
many commercial and in-house government development organizations already employ practices
that are increasingly consistent with the ALIID vision. It is a major challenge, however, to adapt
these ideas to the kind of arm’s length engagement with development organizations characteristic
of DoD major defense acquisition programs.
Advancing the ALLIID vision involves at least four areas of particular emphasis:
a. Architectural structures and practices. This area includes identification of concepts
of operations for systems of systems, ultra-large-scale systems, 74 and the like. This area
also includes the development of practices for early validation, to assist in getting reliable
early assessment of quality and security outcomes associated with particular architectural
choices.
b. Measurement and process models for cost, progress, and engineering risks. Any
approach based on incremental and/or iterative development must incorporate effective
practices for estimating costs, progress, and risks and then use these practices to reward
developers for value earned. Cost-estimation techniques, for example, could be enhanced
to evaluate both estimated mean values and variances and to support ongoing
74 See https://www.sei.cmu.edu/uls/ for more information.
CMU/SEI-2016-SR-027 | SOFTWARE ENGINEERING INSTITUTE | CARNEGIE MELLON UNIVERSITY 288
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