The role of structure: a dependability perspective

8 Summary

Any development aimed at producing a dependable system should pay careful attention to issues of structuring. Any old structuring will not do — poor structuring can harm system performance, and impede system maintenance and evolution. But weak structuring can directly impair dependability. Structuring is in fact not an option — it would seem that the only way that humans can recognise entities and attempt to cope with complexity is by presuming — and then relying on — structure. The problem is to ensure that there is an effective reality to back up such presumptions, and that this reality can survive and evolve as needed for the successful continued deployment of the system.

We have attempted to maximize the use of notions from technical systems on whole (computer-based) systems; this is in no way intended to deny or ignore the differences between the ways in which human “components” and technical components contribute to the dependability problems, and solutions, of computer-based systems. However it does, we believe, allow a number of useful general issues to be identified and addressed.