Rules and Recommendations for Using System Symbols

The general rules and recommendations for using system symbols are described in z/OS MVS Initialization and Tuning Reference.

As a example, suppose that you require two members (named SYS1 and SYS2) to share the following LOGON(2) initialization statement. 
LOGON(2) APPLID=jes&SYSNAME;,...
You have defined &SYSNAME; as SYS1 on member SYS1, and &SYSNAME; as SYS2 on member SYS2. Following symbolic substitution, the LOGON(2) statement for each member appears as: 
LOGON(2) APPLID=JESSYS1,...   /* Init statement for member SYS1 */
LOGON(2) APPLID=JESSYS2,...   /* Init statement for member SYS2  */

Do not code system symbols in JES2 initialization statements that are to be processed by members that are below the JES2 SP 5.2 level. Those members cannot substitute text for system symbols in JES2 initialization statements.

Parent topic: Sharing JES2 Initialization Statements