Software organizations specify their software processes so that process
knowledge can be systematically reused across projects. However, different
projects may require different processes. Defining a separate process for each
potential project context is expensive and error-prone, since these processes
must simultaneously evolve in a consistent manner. Moreover, an organization
cannot envision all possible project contexts in advance because several
variables may be involved, and these may also be combined in different ways.
This problem is even worse in small companies since they usually cannot afford
to define more than one process. Software process lines are a specific type of
software product lines, in the software process domain. A benefit of software
process lines is that they allow software process customization with respect to
a context. In this article we propose a model-driven approach for software
process lines specification and configuration. The article also presents two
industrial case studies carried out at two small Chilean software development
companies. Both companies have benefited from applying our approach to their
processes: new projects are now developed using custom processes, process
knowledge is systematically reused, and the total time required to customize a
process is much shorter than before.