The System library (TBSYSLB) contains all of the system Views that are used by tablesONLINE/CICS for table definition and utility functions. This library also contains tables that are used internally by tablesONLINE/CICS, like the Cursor Positioning table and Session ID table. The System library is read-only and can be shared by all CICS regions using tablesONLINE/CICS.
These Views and tables have write passwords and are not intended for public use. The exceptions are the Session ID table that is used to delete sessions, the TBSYSVTS table which is used to control which VTS-TSRs or local TSR to load/access tables from, the MRO table and the Constants table, all of which are described in tablesONLINE/CICS Administration.