General Considerations

Command processors that receive their input from SSI function code 10 should consider:

Using the 4-byte console ID. This is found in the SSCMCNID field of the SSCM control block. An application that uses the MCSOPER interface (see MCSOPER in z/OS MVS Programming: Authorized Assembler Services Reference LLA-SDU can only be assured of receiving the command response by using this field on a WTO. If a 1-byte console ID must be used, use the value in the SSCMSCID field. Please note, however, that the 1-byte console ID found in the SSCMSCID field cannot guarantee the command response message will reach the MCSOPER user who issued the command. Instances of 1-byte console ID usage will be recorded by the Console ID Tracking facility, which is invoked with the CNZTRKR macro. For information regarding the removal of 1-byte console IDs in favor of 4-byte console IDs, see z/OS MVS Planning: Operations.
Using the SSCMAUTH field. Use the flag settings of the SSCMAUTH field to test the command authority of the caller. This field is mapped by the UCMAUTH field in the UCME (IEECUCM).
Using the SSCMCART field. All command response messages issued through a WTO should use the values passed in the SSCMCNID field (above) and in the SSCMCART field. The use of these values ensures proper delivery of the message to the command issuer.

Considerations for Command Processing Calls in a Sysplex:

In a sysplex, command processing SSI calls are made to subsystems:

On the originating console's system only, when the command is not routed to any other system in the sysplex.
On the originating console's system only, when the command is routed to another system in the sysplex as the result of the location (L=) operand on the command or the specification of a console by name.
On the receiving system only, when it is a prefix command that is routed through the MCS command prefix facility.
On both the originating system and the receiving system, when the ROUTE command is issued, as follows:
- On the originating system for the ROUTE command.
- On the receiving system for the command that is routed.

Considerations for Commands That Specify System Symbols:

When a command contains system symbols, MVS™ provides the command text to the SSI after it substitutes text for the system symbols. For example, if the following command is entered to display a console group on system SYS1:

   DISPLAY CNGRP,G=(CN1GRP&SYSCLONE.)

The SSI receives the following text (assuming that the default for &SYSCLONE., the last two characters of the system name, is taken):

   DISPLAY CNGRP,G=(CN1GRPS1)

If the function routine requires the original command text (the one that existed before symbolic substitution), it can access the SSCMOLIB field in the SSCM (see z/OS® MVS Data Areas in the z/OS Internet library (http://www.ibm.com/systems/z/os/zos/bkserv/) for a description of the IEFSSCM mapping macro, which maps the SSCM).

Do not use the function routine to add or change system symbols in command text. The system cannot substitute text for system symbols that are added or changed through the SSI.