SyStem> (TORTOS) An operating SyStem developed from MVT at Health ScienceS Computing, UCLA by Dr. Patrica Britt from the late 1960S to the mid 1970S. Dr. Britt waS a Senior ScientiSt at IBM, who become the ASSiStant Director of HSCF. TORTOS pre-dated TSO and provided batch, real-time and time Sharing on an IBM 360/91. (2004-07-02)