A large-scale dual operating system

Abstract

The UT2D operating system is a large high-performance batch and time sharing system which runs on a dual mainframe configuration consisting of a CDC 6600 and a CDC 6400 sharing an Extended Core Storage unit and all of their disks. It was developed locally at the Computation Center of the University of Texas at Austin, in an evolutionary process which started with a simple batch system. UT2D is of general interest because of its successful use of a dual configuration, because of its ability to support a large and varied load of both batch and interactive jobs, and because it demonstrates that evolutionary development by a small programming staff can succeed with a large system. Furthermore, UT2D contains some unusual features such as a built in event recorder for performance evaluation and a distributed tape-based permanent file system. This paper describes the evolution, design principles, and unusual features of UT2D. An outline is provided here for the sake of the reader who is interested in specific topics.