The format of the MSGDISP macro with the MOUNT parameter is:

>>-+-------+--MSGDISP--MOUNT--,UCB=(reg)------------------------>
   '-label-'                               

>--+------------------+--+-------------------+------------------>
   |         .-'S'--. |  '-,MF=-+-L--------+-'   
   '-,LABEL=-+-'A'--+-'         '-(E,addr)-'     
             +-'N'--+                            
             +-'X'--+                            
             '-addr-'                            

>--+--------------------+--+--------------+--------------------->
   '-,SER=-+-'volser'-+-'  '-,MEDIATYPE=n-'   
           '-addr-----'                       

>--+-----------------+--+----------------+---------------------->
   |         .-YES-. |  |        .-NO--. |   
   '-,INDEX=-+-NO--+-'  '-,TEST=-+-YES-+-'   

>--+----------------+------------------------------------------><
   |        .-YES-. |   
   '-,WAIT=-+-NO--+-'   

MOUNT

Displays an 'M' in position 1 of the display area during a mount request. The 'M' is followed by a volume serial number and label type. The display flashes on and off until a volume is loaded and ready. If the device is ready at the time a mount request is issued, the 'M' is not displayed.

UCB=(reg)—(2-12)

Specifies a register containing the UCB address for the device. Use the address of a UCB, not a UCB copy.

LABEL='A' or 'N' or 'S' or 'X' or addr

Displays the label type of the mounted volume in position 8. If you specify an unknown label type other than a blank, a "?" is displayed.

'A'

Specifies ISO/ANSI (AL) or ISO/ANSI with user labels (AUL). Apostrophes are required.

'N'

Specifies no labels (NL), LTM (VSE), or bypass label processing (BLP) Apostrophes are required.

'S'

Specifies IBM® Standard (SL) or IBM Standard with user labels (SUL). Apostrophes are required.

'X'

Specifies nonstandard labels (NSL). Apostrophes are required.

addr—RX-type address, A-type address, or (2-12)

Specifies the address of an area containing an “A”, “N”, “S”, or “X”. (See the following explanations of these characters.) For MF=L, you can only specify an A-type address.

MF=L or (E,addr)

Specifies either the execute or the list form of MSGDISP. If you do not specify this parameter, the standard form of the macro is used.

L

Specifies the list form of MSGDISP. This generates a parameter list that can be used as input to the execute form. The execute form can modify the parameter list.

(E,addr)

Specifies that the execute form of the macro and an existing parameter list are used.

addr—RX-type address, (1), or (2-12)

Specifies the address of the parameter list.

SER='volser' or addr

Specifies the serial number of the volume to be mounted. The serial number is displayed in positions 2 through 7. If you do not specify SER, the system supplies the volume serial number. If the serial number is not available, a scratch volume is used, unless the volume use attribute indicates a default of "PRIVAT".

'volser'

Specifies the volume serial number as a literal. Specify in apostrophes.

addr—RX-type address, A-type address, or (2-12)

Specifies the address of the volume serial number. For MF=L, you can only specify an A-type address.

MEDIATYPE=n

Specifies what media type to mount for SCRTCH or PRIVAT mounts. The MEDIATYPE keyword applies only when volumes are to be mounted on devices that reside in a Manual Tape Library (MTL). If MEDIATYPE is specified for devices outside of a Manual Tape Library, it is ignored. The value n can be specified as a literal, the address of a 1 byte field containing the value, or the name of the addressable field containing the value. Valid values for MEDIATYPE are the numbers 1 through 8.

TEST=NO or YES

Specifies whether the macro expansion is to include code that tests the UCB to determine whether message display is supported. If the result of the test is that the message display is not supported, an SVC is not invoked.

NO

Specifies that the macro expansion is not to include code that tests the UCB to determine whether the device supports message display.

YES

Specifies testing the UCB by the MSGDISP macro before attempting to invoke the message display service routine.

Requirement: TEST=YES requires you to include the UCB mapping macro (IEFUCBOB) in the source code.

Restriction: There is a restriction when using TEST=YES. Programs running in AMODE 24 and invoking the MSGDISP macro with the TEST=YES parameter cannot pass the actual address of a UCB that resides above the 16 MB line. These programs must pass the captured UCB address or, if an actual address is passed, the UCB must reside below the 16 MB line.

INDEX=NO or YES

Specifies whether the automatic cartridge loader (ACL) should be indexed to satisfy a scratch mount request.

NO

Specifies that indexing should not be done regardless of the state of the ACL.

YES

Specifies that indexing should be done if:

• The ACL is present and loaded, and
• The request is for SCRTCH or PRIVAT.

WAIT=NO or YES

Specifies when control is returned to you.

NO

Specifies that the MSGDISP function is not to wait for completion of I/O initiated on the caller's behalf. When MSGDISP returns, the I/O request might still be running. I/O return codes are not returned, and I/O errors are recorded in the same manner as any permanent error by the error recovery procedure.

YES

Specifies that control is to be returned after I/O is complete.