Software Complexity and Modeling ◾ 13
Standalone systems, such as word processors, simple databases, and
games, may be sold to any customer if designed with sucient general-
ity. Alternatively, such systems may be targeted toward more specialized
communities such as education and medicine. Custom soware typically
requires specic contracts for product development. Common examples
include embedded systems, aircra, military, and government. Oen such
systems have enhanced requirements for security and/or preservation of
proprietary information.
Perceived as an essential but costly stage of soware development, so-
ware maintenance spans all stages of the SDLC and encompasses dierent
types of modications. When expanded functionality a ...