SYSOUT

SYSOUT is a ddname used in IBM mainframe batch processing, notably in JCL (Job Control Language). It designates the destination for a step’s standard output, typically routing data to the system’s spool, a printer, or a dedicated output dataset. SYSOUT output is managed by the system’s output management facilities, and it is commonly contrasted with other DD names such as SYSIN (input) and SYSPRINT (program listings or diagnostic output).

In a JCL job, a step can direct its output by defining a DD statement with the name SYSOUT. The actual destination is determined by site-defined output classes and device definitions. The value assigned to SYSOUT may indicate a class, a specific destination, or the default spool location, depending on the system’s configuration. Output routed through SYSOUT usually ends up in a print queue or a held/spooled dataset, from which it can be printed, stored, or routed to further processing.

Typical usage is simple: a DD statement with SYSOUT can be given a keyword such as SYSOUT=* or SYSOUT=A, though exact values depend on the site’s conventions and the operating system version. For example, SYSOUT=* often routes to the default spool class, while SYSOUT=A selects a predefined output class named A. The actual behavior—form size, destination printer, and retention policy—depends on the system’s printer and spool definitions.

SYSOUT is commonly used alongside related DD statements like SYSIN (input data) and SYSPRINT (diagnostic listings). It is a core mechanism for directing program output in batch processing environments. See also SYSIN and SYSPRINT.