CSSL(Continuous System Simulation Language) versions I, II,

III, IV and V have been commercially available since 1968.

CSSL-I was developed for Jet Propulsion Labs in 1968.

CSSL-III was widely distributed from 1969-1975. CSSL-IV

(interactive version) was developed by R. Nilsen and ran on

over 30 different computers. Currently CSSL-V is marketed by

Simulation Services International and available on PCs and

workstations.