Thanks!

The documents highlight by Albert Rafetseder help me to find some answers.

From Miller's writing "The Deadly Embrace Between Music Software and Its Users" (http://msp.ucsd.edu/Publications/pdf_EMS14_puckette.pdf), I would synthetise as follow.

The three most important criteria in development of Pd:

• longevity:
• limit of maintainability < 100 000 lines of code (not 10 000 indeed !)
  
• usable lifetime of 50 years : avoid adding any but the most carefully justified and planned extensions now
• new versions of Pd should run older patches compatibly (For me, it sounds like the first criteria)
  
• Pd should never stop working unexpectedly during a live performance

<3

j.