The TBOPEN service reads a permanent table from the table input file into virtual storage, and opens it for processing. TBOPEN should not be issued for temporary tables.
An ENQ is issued to ensure that no other user is currently accessing the table. The ENQ applies only to the specified table in the table (member) in the table input library, not the entire library. For the WRITE option, an exclusive ENQ remains in effect until the table is closed. For the NOWRITE option, a shared ENQ remains in effect only during the time that the table is read into storage.