The Free On-line Dictionary of Computing (30 December 2018):

Interactive Data Language

   (IDL) A commercial array-oriented language with numerical
   analysis and display features, first released in 1977.  It
   supports interactive reduction, analysis, and
   visualisation of scientific data.  It is sold by Research
   Systems, Inc.

   Version: 3.6.1 runs under Unix, MS-DOS, MS Windows,
   VAX/VMS and Macintosh.

   Not to be confused with any of the other IDLs.

   (ftp://gateway.rs.inc.com/pub/idl).

   E-mail: .

   (1994-10-07)