A variation of the PICK database programming language. In a nutshell, Unidata uses flat nested tables that can be relationally linked. The first form of this language (PICK) was invented in the late 1960's by some TRW engineers working for the U.S. government on a Cheyenne helicopter program. Ardent (at www.ardent.com) is the current owner of Unidata (Jan. 2001).
This was the fourth language I learned to program in, easier to learn than COBOL, but the code I had to untangle was elderly and fairly convoluted