For most people, this means predictable episodes of frustration, but for the US military, it's a more serious problem. DARPA's new Building Resource Adaptive Software Systems (BRASS) project aims to take a major shot at avoiding this obsolescence by developing software systems that can still operate properly a hundred years from now.

As systems become more complex, the problems of compatibility and obsolescence become more important. Perfectly good devices may be unusable, vital data may be inaccessible, and communications may be impossible. A simple example of this is the BBC Domesday Project of the 1980s, which digitized the famous 11th century Norman census of England's assets. The project was successful, but the LaserVision discs that the data was stored on were almost forgotten until 2002 when it was realized that their formatting was obsolete and would soon be impossible to access, resulting in a major preservation effort.