Just before the job step program is invoked, the Tachyon Operating System can call an initialization user exit. This user exit is called in supervisor state and can therefore install SVCs, modify or create control blocks and perform any other customization.
The initialization user exit program must be in the Link Pack Area and must be named IEFUJI. If this module is found in the LPA, the Tachyon Operating System will call it after initializing all control blocks and just before calling the job step program. The calling conventions for the initialization user exit are very similar to the OS/390 IEFUJI user exit program. The Tachyon Operating System ignores the return code from IEFUJI. If the initialization user exit wants to prevent the job step from executing, it should use the ABEND service.
More information about the calling conventions and parameter list of the IEFUJI program can be found in the IBM manual entitled MVS/ESA Installation Exits (order number SC28-1459). A sample IEFUJI exit is provided in &SYSDIR\samplib\iefuji.390 where &SYSDIR is the directory into which the Tachyon Operating System was installed. An assembled and linked version is provided as &SYSDIR\samplib\iefuji.lpa. To use this version, move iefuji.lpa to the installation directory.