SYSE.13:10 - Rationale

The configuration basis is an episteme for one engineering decision. Starting from one decision makes the boundary and maintenance burden testable. Keeping actual Systems, variant descriptions, software packages, installed realizations, episteme editions, baselines, and status claims separate prevents the situation in which every record is valid but no one knows which unit may be changed or released.

Effectivity is load-bearing because change rarely applies uniformly across a family. Time is only one condition; another condition—for example, serial unit, lot, site, installed part, software realization, environment, or operating envelope—may determine applicability.