Accidental Architecture
Most IT departments have the best intentions of providing the best quality, coherent solutions, yet market conditions, projects running in parallel and various constraints on budgets, resources or time, often causes what might be defined as Accidental Architecture.
The easiest way to identify cases where you’ve been hit by accidental architecture is when describing your it architecture and look for the works “except” or “but not”. Typical examples include - we have a single-sign system utilized everywhere except…”, “We update all systems to current versions, but not this old system…”.