Define an I/O device as static, installation static, or dynamic
With MVS/ESA SP V4, the ability to define I/O devices as static, installation static, or dynamic was introduced through HCD.
A Static device is a device that cannot be dynamically added, deleted, or modified in the software configuration definition. Therefore, the device is not available for use until the next IPL of MVS™.
An Installation Static device is a device that can be dynamically added to the software definition but cannot be modified or deleted dynamically. Or, the device can be dynamically added, deleted, and modified in the hardware configuration definition.
A Dynamic device is a device whose device definition can be dynamically added, deleted, and modified in the software and hardware definition.
You cannot swap a device with different device attributes. This means that a device with an attribute of Dynamic cannot be swapped to a device with an attribute of Installation Static, or vice versa. Attempts to do so result in message "IGF513I - DEVICE devnum INVALID FOR SWAP - DYNAMIC/STATIC INCOMPATIBLE" being issued.
When a device attribute is changed from Installation Static to Dynamic, its UCB address changes. Programs within the system that save UCB addresses encounter problems if an attempt to use that UCB that was valid when the device was Installation Static.
The following table describes the type of swap migrations that are allowed by the MVS operating system:
| TARGET VOLUME | |||
|---|---|---|---|
| Source Volume | Dynamic | Static | Installation Static |
| Dynamic | YES | NO | NO |
| Static | NO | YES | YES |
| Installation Static | NO | YES | YES |
The type of device configuration is determined by the Unit Information Modules (UIM) of the operating system with the Dynamic=No or Dynamic=Yes parameter in HCD. DASD devices are allowed to be Dynamic or Installation Static based on the Dynamic parameter. Therefore, TDMF is not concerned with Static devices.
Take the following steps to determine the device configuration of a volume.
- Open an IPCS session, and set the default to ACTIVE.
- Go to option 6 and issue LISTUCB addr for the specific device.
- Locate the NXUCB data field in the display of the control block (UCBOB + 8).
If the NXUCB data field is zero, the device has a configuration of Dynamic. If the NXUCB data field contains an address, the device has a configuration of Static or Installation Static. Scroll to the bottom of the display to see if the device is Static, Installation Static or Dynamic.
If a TDMF Swap migration is attempted with different device configurations, TDMF issues the message "GTD1230S - Both volumes of a Swap migration must be either Dynamic or Installation Static".
For more information, see the applicable OS/390® HCD Planning, or the applicable MVS/ESA HCD Planning topics "Defining Whether an I/O Device Will be Dynamic" and "Redefining the Dynamic Parameter for an I/O Device".