Individuals and organizations increasingly use sophisticated software
systems from which they demand great reliance. "Reliance" is contextually
subjective and depends on the particular stakeholder's needs; therefore, in
different circumstances, the stakeholders will focus on different 
properties of such systems, e.g., continuity, availability, performance,
real-time response, ability to avoid catastrophic failures, capability of
resisting adverse conditions, and prevention of deliberate privacy
intrusions. The concept of dependability enables these various concerns to
be subsumed within a single conceptual framework.
Achieving dependability is a major challenge, which has spawned many
efforts both at national and international levels. This work is part of the
High Dependability Computing Program (HDCP), a five-year cooperative
research agreement between NASA and various universities and research
centers to increase NASA's ability to engineer highly dependable software
systems.
HDCP brings together, under the common goal of improving systems
dependability, a large and heterogeneous group of actors, from industry and
academia alike, with various perspectives, and different (sometimes even  
conflicting) needs. Thus, the polysemous nature of the concept of
dependability, while unifying so many different efforts, brings also the
risk of creating confusion, making the task of developing dependable
systems even more difficult.
UMIACS-TR-2004-43