Displaying device status and allocation (U)
- All devices
- A specific device type
- Online devices
- Offline devices
- Allocation information (that is, jobname and ASID)
- A range of devices
- Automatically switchable devices
- Unavailable devices
The DISPLAY U command can also display the job names and ASIDs of device users. Knowing the jobs and ASIDs using a particular device can help you determine if you can or cannot take a particular device offline.
To compare this DISPLAY U command with the DEVSERV PATHS command, see Displaying the status of devices and availability of paths.
- The system is to display unit status information about all devices or about specified devices, including non-supported devices (those devices defined in the IODF as DUMMY devices) and channel-to-channel (CTC) links.
- The device class for which the system is to display unit status information. You can enter any
one of the following operands for device type:
- CTC — channel-to-channel (CTC) adapters
- DASD — direct access storage devices
- GRAPHIC — graphic devices
- TAPE — magnetic tape units
- TP — communication equipment
- UR — unit record and dynamic switches
- ALL — all options displayed (equivalent to specifying DISPLAY U)
- The system is to display information (in message IEE457I) about only those devices of the specified device type that are online. If you do not specify a device type, the system displays information about all online devices.
- The system is to display information (in message IEE457I) about only those devices of the specified device type that are offline. If you do not specify a device type, the system displays information about all offline devices.
- The system is to display allocation information (in message IEE106I) for any specified device
that is allocated. Allocation information includes the job name and address space identifier (ASID)
of each job to which the device is currently allocated.
Tip: MASTER address space allocation could be caused by data sets in an active but unallocated LNKLST residing on that volume.
- AUTOSWITCH or AS
- The system is to display information the coupling facility has about one specific tape device or all tape devices that are defined as automatically switchable. AUTOSWITCH is valid only for tape devices (that is, for a deviceclass of TAPE.) If you omit deviceclass, the system displays information about all automatically switchable tape devices. If a device is offline to the issuing system, the information specifies that the device is offline (“OFFLINE” in the STATUS column) and does not provide any other information about the device.
- UNAVAILABLE or UNAVAIL
- The system is to display information (in message IEE457I) about the OFFLINE and UNAVAILABLE tape devices. When one or more devices are offline and unavailable, the UNIT and TYPE are displayed in message IEE457I. UNAVAILABLE is valid only for tape devices (that is, for a deviceclass of TAPE.) If you omit deviceclass, the system displays information about all offline and unavailable tape devices.
- The system is to display information about the status of automatically switchable devices on the system named sysname.
- The system is to display information (in message IEE457I) about the device from which the system was initially loaded (IPL'ed). For additional IPL information use the DISPLAY IPLINFO command.
- The volume serial of the device for which the system is to display unit status information in message IEE457I.
- The system is to display unit status information about devices starting with device
number devnum for nnnnn number of devices.
devnum is a 3-5 digit hexadecimal device number, optionally preceded by a slash (/).
If you omit the device number, the system assumes the starting device number is X'000'.
ALLOC does not support 5-digit device numbers and will fail with IEE453I.If you omit the number of devices to be displayed (nnnnn) and
- specify ALLOC the system assumes the number of devices to display to be 8
- do not specify ALLOC the system assumes the number of devices to display to be 16
The system displays status information for primary paths only.
- L=a, name, or name-a
- Specifies the display area (a), console name (name), or
both (name-a) where the display is to appear.
If you omit this operand, the display is presented in the first available display area or the message area of the console through which you enter the command.
- If you specify a device number that was not specified in the IODF during system installation, the display starts with the next higher device number that was specified.
- For multiple-exposure devices (supported pre-MVS/ESA SP 5.2), the value you specify for devnum must be the same as that specified in the IODF.
- For parallel access volumes, if you specify an alias device number, the system ignores it and starts with the next device number that is not an alias device number.
- When the system displays the device type for an MCS or SMCS console as a 3270 model X, HCD identifies it as a 3270 console.
- For autoswitchable devices, a DISPLAY U command without the AUTOSWITCH parameter may display a volume serial number other than for the currently mounted volume if the device is assigned to a different system. Use the AUTOSWITCH parameter to display up-to-date information for such a device.