Time Sharing Option (TSO) is an interactive command line interpreter for IBM mainframe operating systems such as MVS/ESA, OS/390 and z/OS. It fills the same purpose as a command shell like Bash on Unix, or cmd on Windows. TSO is normally used by mainframe system administrators and programmers. For more information see the book MVS TSO by Doug Lowe.

So named since when it was originally introduced in the 1960s, time-sharing was considered an "optional feature", and hence TSO was offered as an optional feature of OS/360.

TSO is rarely used in production shops alone, most mainframe interaction is actually via the ISPF facility which allows for customized menu-driven interaction, the combination is referred to as TSO/ISPF.

See also

• Michigan Terminal System
• Multics
• MUSIC/SP
• ISPF

Mainframe computers

Time-Sharing Option | Time Sharing Option | Time Sharing Option | Time Sharing Option