Failed what? In its domain, it succeeded in its goals: a high reliability platform for aerospace, defense, and other mission critical domains. It was mandated by the US DoD for all software in the nineties and used in Airbus avionics and aboard the ISS, etc.
Its syntax and concepts were considered solid and so was selected as the basis of the VHDL hardware description language, also successful in its domain.
Its syntax and concepts were considered solid and so was selected as the basis of the VHDL hardware description language, also successful in its domain.