DEVICE (Define I/O Devices)

Use this form of the DEVICE statement to define a device that JES3 can use:

to satisfy its own functions (JES3 device).
to satisfy the needs of a job (execution device).
as a JES3 device or as an execution device (shared device).

Because JES3 varies assignable devices and all execution devices online or offline to MVS™ and to JES3 at initialization, satisfy all conditions necessary for the MVS VARY command to execute properly before initializing JES3.

If you want two or more mains to share a device, use the XUNIT parameter to define each main. These devices are called shared devices.

Deciding whether to specify a device as shared or not (using the XUNIT parameter) depends on how the device is attached to the system. Channel-attached devices, such as 3900 printers, that you want to operate under the control of an output writer functional subsystem (FSS), must be defined as shared. Those other devices (ex: 3827 printers), which you want to operate under control of an FSS yet are not channel-attached, must not be defined as shared.

Except for RJP devices, you must code one DEVICE statement for each I/O device that you want JES3 to use.

For more information on defining I/O devices, see “Defining I/O Devices to JES3” in z/OS JES3 Initialization and Tuning Guide.