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

Imperial Software Technology

    A software engineering company which emerged from
   Imperial College in about 1982.  It enjoys a world-wide
   reputation for technical excellence as a software product and
   technology provider in the Open Systems market.  Its flagship
   product is X-Designer, the award-winning graphical user
   interface builder.  It also has considerable expertise in the
   Z language and Formal Methods.

   (http://ist.co.uk/).

   (1995-11-23)