Sustaining Software-Intensive Systems

As today's systems become increasingly reliant on software, the issues surrounding sustainment become increasingly complex. The risks of ignoring these issues can potentially undermine the stability, enhancement, and longevity of fielded systems. Questions about sustaining new and legacy systems include 1. What does it mean to perform sustainment from a software perspective? 2. What types of development and acquisition activities are required to sustain software-intensive systems? 3. Although the Department of Defense (DoD) has a technical definition of sustainment, does the DoD typically consider sustainment as maintenance? 4. How does the increased use of commercial-off-the-shelf software complicate sustainment? This technical note discusses these questions and presents definitions, related issues, future considerations, and recommendations for sustaining software-intensive systems. Sustainment done well leads to well-supported software-intensive systems and reduced total ownership costs and should help organizations meet current and new mission area and capabilities requirements. The information contained in this technical note is based on information that the Software Engineering Institute gathered during work with Air Force software-intensive systems. While the information is pertinent and can be applied to systems in the commercial sector, keep in mind minimal effort was made to convert "DoDspeak" into commercial sector language.