The IT systems today must enable satisfactory services to be provided to users continuously by adapting the systems to accommodate ever-changing objectives and environments and to manage unpredictable failures.

Accountability to society when failure of services has occurred needs to be achieved.

This capability is called "OSD: Open Systems Dependability". DEOS is a body of knowledge needed to achieve OSD.

To realize OSD, that is to achieve service continuity and accountability for ever-changing systems, the following is indispensable.

• DEOS Process: an iterative process for achieving kaizen, continuous improvement.
• DEOS Architecture: an architecture that supports a DEOS Process.
• Elemental Processes and Technologies: processes and technologies to realize individual functions.