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

System Control Language

    (SCL) The command language for the VME/B
   operating system on the ICL2900.  SCL was block
   structured and supported strings, lists of strings
   ("superstrings"), integer, Boolean, and array types.
   You could trigger a block whenever a condition on a variable
   value occured.  It supported macros and default arguments.
   Commands were treated like procedure calls.

   ["VME/B SCL Syntax", Intl Computers Ltd. 1980].

   (2003-01-08)