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

Digital Simulation Language

    (DSL) Extensions to Fortran to simulate analog
   computer functions.  Version DSL/90 ran on the IBM 7090.

   ["DSL/90 - A Digital Simulation Program for Continuous System
   Modelling", Proc SJCC 28, AFIPS, Spring 1966].

   [Sammet 1969, p 632].

   (1996-10-13)