What Does Application Development Facility Mean?
The Application Development Facility (ADF) is an IBM-developed 4GL application package to be used with IMS databases. A programmer is able to define a set of rules using the Application Development Facility, which, when combined with a simple screen printer, could be used to create an IMS DC application. The codes being programmed are more like logical transactions rather than full programs, allowing the smooth transition to DBMS and new computer types that eventually upgraded the entire application set.
Techopedia Explains Application Development Facility
The Application Development Facility was popular in the early '80s for quickly developing applications for the large IMS DB/DC environments. It was mostly used to develop overly simple systems with very small budgets, but some companies used it as their main tool, even for developing complex online systems.
By the mid-'80s IBM had also developed another 4GL product, the Cross System Product (CSP), which it favored over the ADF for development because it supported more platforms/OSs compared to the ADF. In 2003, sales of ADF were discontinued, but support is still provided to any customer still using it.