Displaying device status and allocation

Use the DISPLAY U command to help you keep track of the status (that is, the availability for allocation) of the devices attached to the system. This command lets you request the status of:
  • 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.

Syntax

 
D U{[,deviceclass][,ONLINE ][,[/]devnum[,nnnnn]]                   }
                 [,OFFLINE][,[/]devnum[,nnnnn]]                    
                 [,ALLOC  ][,[/]devnum[,nnnnn]]                                  
                 [,AUTOSWITCH|AS][,[/]devnum[,nnnnn]][SYS=sysname]  
                 [,UNAVAILABLE|UNAVAIL][,[/]devnum[,nnnnn]]      (See Note)
  
   {,IPLVOL}
  
   {,VOL=volser}

   [,L={a|name|name-a}]
Note: Supply all commas between DISPLAY U and a specified operand. For example, DISPLAY U,,OFFLINE.

To compare this DISPLAY U command with the DEVSERV PATHS command, see Displaying the status of devices and availability of paths.

Parameters

U     
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.
deviceclass
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)
ONLINE
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.
OFFLINE
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.
ALLOC
The system is to display allocation information (in message IEE106I) for any specified device that is allocated. Allocation information includes the jobname and address space identifier (ASID) of each job to which the device is currently allocated.
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.
SYS=sysname
The system is to display information about the status of automatically switchable devices on the system named sysname.
IPLVOL
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.
VOL=volser
The volume serial of the device for which the system is to display unit status information in message IEE457I.
Note: If you do not specify ONLINE, OFFLINE, or ALLOC, the system displays status information, without allocation information, about both online and offline devices.
[/]devnum,nnnnn
The system is to display unit status information about devices starting with device number devnum for nnnnn number of devices. devnum is a 3-digit or 4-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'.

If you omit the number of devices and do not specify ALLOC, the system assumes the number of devices is 16. If you omit the number of devices and specify ALLOC, the system assumes the number of devices is 8.

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.

Notes:
  1. 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.
  2. 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.
  3. 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.
  4. 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.
  5. 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.

Examples

Example 1:
To list the status of the first ten (if any) direct access devices with device numbers of 400 or higher, enter: 
D U,DASD,,400,10
Example 2:
To list the users (jobnames and ASIDs) of the first eight allocated devices with device numbers of A250 or higher, enter: 
D U,,ALLOC,/A250,8
or 
D U,,ALLOC,/A250
Example 3:
To list the status of a device specified by the volume serial number D72665, enter: 
D U,VOL=D72655
Example 4:
To list the status of the automatically switchable tape device with the device number of 270, enter: 
D U,,AUTOSWITCH,270,1
Example 5:
To list the status of the first 16 automatically switchable tape devices with device numbers of 000 or higher on the system named GRS127, enter: 
d U,,AUTOSWITCH,,,SYS=GRS127
Parent topic: DISPLAY command