as guests of a third systemVM/XA. This way, the new MVS/XA system could be tested while the old production OS/VS1 system was still in use. On January 24, 1989, IBM announced the intention to withdraw OS/VS1 and OS/VS1 BPE from marketing effective April 24, 1989, and to discontinue service effective February 28, 1990. Time-sharing Although IBM's Time Sharing Option (TSO) required VS2, customers with a 370/145 or 370/148 had other time-sharing options. One combination was VM/CMS for time sharing, and a guest "machine" running OS/360 MFT II for batch. Conversational Remote Job Entry Optional component of OS/360 MFT II, OS/360 MVT and OS/VS1, CRJE allowed the user at a line-mode terminal to edit text datasets, submit jobs and access job output. TONE for VS1 A non-IBM time-sharing product named TONE (TSO-like, for VS1 / VS ONE) was marketed by Tone Software Co. References Further reading Functional structure of IBM virtual storage operating systems, Part I: Influences of dynamic address translation on operating system technology, by M. A. Auslander and J. F. Jaffe, IBM Systems Journal, Volume 12 (1973), No 4, Page 368 OS/VS1 Concepts and Philosophies, by T. F. Wheeler, Jr., IBM Systems Journal, Volume 13 (1974), No 3, Page 213 The job entry subsystem of OS/VS1, by J. H. Baily, J. A. Howard, and T. J. Szczygielski, IBM Systems Journal, Volume 13 (1974), No 3, Page 253 (The OS/V1 job entry subsystem was named JES1) IBM mainframe operating systems 1972 software