Those code bases were started in the mid to late 70s. MUMPS was hot shit at the time, at least for health care software. The language was created at Massachuse

Those code bases were started in the mid to late 70s. MUMPS was hot shit at the time, at least for health care software. The language was created at Massachusetts General Hospital (affiliated with Dana Farber Cancer Institute and Harvard), put into the public domain, used be the VA (VistA), and others. Advantages (at the time): freely available, everybody else is using it, easy to learn, interpreted, good performance on resource constrained hardware, multi-process/multi-user support, built in database/persistent storage.