Advanced Topics › How You Change the Status of Managed Devices (VARY) › Respond to ASSIGN Processing Requests

Respond to ASSIGN Processing Requests

Note: Any references in the following section to “assignable” tape devices include the following: 3480, 3490, 3590, and any other type of compatible device.

When you bring an assignable tape device online, z/OS issues an ASSIGN request for that device. The ASSIGN request indicates which system or group of systems can use that device. By default, z/OS assigns the device exclusively to the current system. You also can allow multiple systems to assign the device by issuing the z/OS command VARY ONLINE,SHR. This enables any system that provides the correct password to use the device.

You can tell GTAF to intercept ASSIGN requests for GTAF managed devices by using the GTAINIT ASSIGN statement.

Note: For more information, see the Statement and Command Reference Guide.

When you specify MULTISYSTEM, you must use the same value for ASSIGN on all systems that will be sharing the devices. For example, if you want systems A and B to share a group of devices (by providing the password “ NON-JES”), you must specify the following for both systems:

GTAINIT ASSIGN=(MULTISYSTEM,' NON-JES')

Use of different assign passwords in a multiple MIMplex environment is beneficial when both MIMplexes have access to the same devices. Devices brought online to a system in one MIMplex can only be brought online to other systems in the same MIMplex that supply the correct password. In other words, a device can only be online to one MIMplex at a time. Using the same assign password in two separate MIMplexes causes dual allocations if a device is brought online to both MIMplexes.

Important! All assignable devices must be offline to all systems before you start CA MIM if you are changing the value of the ASSIGN parameter since the last time GTAF was started.