Rotting Design Awareness Bob Martin speaks of four main symptoms that indicate a software design is rotting. Reference: http://www.objectmentor.com/resources/articles/Principles_and_Patterns.pdf 1 4 Symptoms of Design Rot - Rigidity - Fragility - Immobility - Viscoscity 1 Rigidity - Symptom -- Even a simple change causes cascading changes in dependent modules -- Changes take long periods of time - Effect -- Managers fear allowing changes, official rigidity sets in, adverse management policy 1 Fragility - Symptom -- Even simple changes cause the software to break in many, sometimes unrelated places - Effect -- Every fix exacerbates the problem, the software becomes impossible to maintain -- Engineering loses credibility and trust by management and users 1 Immobility - Symptom -- Software reuse brings too much non-related baggage - Effect -- Software is rewritten instead of reused 1 Viscosity Design Viscosity - Symptom -- Design preserving changes are harder to employ than hacks (High Viscosity) - Effect -- It is easy to do the wrong thing but hard to do the right thing Environment Viscosity - Symptom -- Compile times take too long, version control check in takes too long, unit testing takes too long - Effect -- A slow development environment causes sub-optimal development decisions, (E.g. skip compile, check in rarely, test rarely) 2007-04-11 00:44:09.0 2007-02-10 01:31:13.0