FINDUCB subcommand — locate a UCB

Use the FINDUCB subcommand to locate the unit control block (UCB) for a specified device. When the subcommand finds the control block, it creates an entry in the symbol table for UCBdddd, where dddd is the device number.

FINDUCB processes the specified device number as follows:

Searches the symbol table for the symbol UCBdddd. If found, IPCS displays the storage associated with that symbol.
Verifies that the device was defined during system initialization.
Locates the device's UCB.

Note:

This subcommand may modify X, the current address.
Casual use of the FINDUCB subcommand is not recommended because FINDUCB's processing requires a great deal of time.

Related subcommands
- FIND
- FINDMOD

Syntax

  {FINDUCB }  device-number
  {FINDU   }

-------- SETDEF-Defined Parameters -------------------------
Note: You can override the following SETDEF parameters.
See SETDEF subcommand — set defaults.

 
              [ ACTIVE | MAIN | STORAGE          ]
              [ DSNAME(dsname) | DATASET(dsname) ]
              [ FILE(ddname) | DDNAME(ddname)    ]
              [ PATH(path-name)     ]
              [ DISPLAY[(display-options)]   ]
              [ NODISPLAY[(display-options)] ]
              [ FLAG(severity) ]
              [ PRINT | NOPRINT ]
              [ TERMINAL | NOTERMINAL ]
              [ TEST | NOTEST ]
              [ VERIFY | NOVERIFY ]

Parameters
device-number

Specifies the device number of the device whose UCB is to be found. The number is 1 to 4 hexadecimal digits; leading zeros are optional.
Return codes
See Standard subcommand return codes for a description of the return codes produced by the FINDUCB subcommand.
Example: Locate the UCB for device number 8000.
- Action
```
COMMAND ===> FINDUCB 8000
```
- Result
  Even if you are using captured UCBs, FINDUCB returns the address of the actual UCB. In this example, the actual UCB address is 01D0E028.
```
UCB8000 - UNIT CONTROL BLOCK FOR CHANNEL TO CHANNEL ADAPTER
LIST 01D0E028 ASID(X'0001') POSITION(X'-0008') LENGTH(48) STRUCTURE(UCBCTC)
```