Time Sharing Option
History of IBM mainframe operating systems |
---|
Time Sharing Option (TSO) is an interactive
.Use
In computing, time-sharing is a design technique that allows many people to use a computer system concurrently and independently—without interfering with each other.[1] Each TSO user is isolated; it appears to each one that they are the only user of the system.
TSO is most commonly used by mainframe system administrators and programmers. It provides:
- A text editor[2]
- Batch jobsupport, including completion notification
- System/360and later IBM mainframes
- Support for other vendors' end-user applications, for example for querying databases
TSO interacts with users in either a line-by-line mode or in a full screen, menu-driven mode. In the line-by-line mode, the user enters commands by typing them in at the keyboard; in turn, the system interprets the commands, and then displays responses on the terminal screen. But most mainframe interaction is actually via ISPF, which allows for customized menu-driven interaction. This combination is called TSO/ISPF. TSO can also provide a Unix-style environment on OS/390 and z/OS via the UNIX System Services command shell, with or without ISPF.
TSO commands can be embedded in
TSO eliminated the need to punch cards on a keypunch machine, and send card decks to the computer room to be read by a card reading machine.
History
When it was originally introduced in 1971,
When first released, TSO module names always had the "prefix" IKJ, plus the second and third letters of the associated pre-TSO functional group (IEA = original functional group of "supervisor", hence a TSO module name of IKJEAxxx, IEB = original functional group of "dataset utilities", hence a TSO module name of IKJEBxxx, etc.).
Batch use
It is common to run TSO in batch (as opposed to interactively): all the usual TSO line-mode interactive commands can be also executed via Job Control Language (JCL) by running any of the programs IKJEFT01
, IKJEFT1A
, and IKJEFT1B
and supplying the line commands in a file pointed to by the SYSTSIN DD
. The primary difference between the three programs is their handling of return codes from the executed commands.
Batch execution of TSO is one way to allow an IBM mainframe application to access
See also
References
- ^ "Time-sharing". Britannica.com. Encyclopaedia Britannica. Retrieved 20 December 2020.
- ^ "EDIT command - z/OS 2.5.0 - TSO/E Command Reference". ibm.com.
- ^ Myers, Steve (Spring 2004). "Dynamic Allocation ~ The MVS Way" (PDF). TSO Times: 5. Archived from the original (PDF) on 2012-04-25.
- ^ "Overview of TSO/E Programming Services", IBM z/OS V1R9.0 information center
Further reading
- Lowe, Doug (1991). MVS TSO, Part 1: Concepts and ISPF (Second ed.). Mike Murach & Associates, Inc.
- Lowe, Doug (1991). MVS TSO, Part 2: Commands And Procedures (Second ed.). Mike Murach & Associates, Inc.
External links
- Several TSO manuals from the early 1970s, available from the BitSavers.org archive