Use this system macro to:
- Mount or dismount a symbolic device address (SDA)
- Request the status of an SDA mount.
Format
- label
- A symbolic name can be assigned to the macro statement.
- FUNCT
- This is the name of the function to be performed. It must be one of
the following values:
- MOUNT
- Specified SDA is to be mounted
- DISMOUNT
- Specified SDA is to be dismounted
- STATUS
- Return the mount status of the specified SDA
- PARM
- This is the required parameter for the function to be performed.
- MOUNT
- This is a label assigned to an area of storage containing a MDR or a
register containing the address of a MDR as defined by the DCTMDR
DSECT. See MSDAC-Mount a Symbolic Device Address (SDA) for more information.
- DISMOUNT
- This is the label of a halfword field containing the SDA or a register
with the SDA in bytes 2-3 and zeros in bytes 0-1. See the DSDAC-Dismount a Symbolic Device Address (SDA) for more information.
- STATUS
- This is a label assigned to an area of storage containing a DDB or a
register containing the address of a DDB as defined by the DCTDDB
DSECT. See ISDAC-Interrogate Symbolic Device Address (SDA) Status for more information.
Entry Requirements
R9 must contain the address of the ECB being processed.
Return Conditions
- Control is returned to the next sequential instruction.
- The contents of R14 are unknown. The contents of R0 - R7 are
preserved across this macro call.
- A code is returned in R15 as follows.
MOUNT:
- 0
- SDA mount was successful.
- 4
- SDA is in-use.
- 8
- SDA is not valid.
DISMOUNT:
- 0
- Dismount was successful.
- 4
- Dismount was unsuccessful.
STATUS:
- 0
- SDA is in-use.
- 4
- SDA is available.
- 8
- SDA is not valid.
- If the extended option is set in the DDB (DDBX = 1) for STATUS, the path
management control words and the subchannel status words are returned in the
area defined by the DCTDDB DSECT.
- The path available mask is returned on a successful mount in the area
defined by the DCTMDR DSECT.
- For MOUNT and STATUS requests, the channel path identifier (CHPID) type
indicator is returned.
Programming Considerations
- This macro can be run only on an I-stream having affinity with the
specified SDA.
- An SDA specification that is not valid for a dismount results in a return
code of 0.
- This macro is for use in a real-time program only.
Examples
None.