Oracle database management SYSTEM tracks data storage through the information stored in the system tablespace. The SYSTEM tablespace contains data dictionaries, as well as (by default) indexes and clusters. The data dictionary contains a table that holds information about user objects in all databases.
Oracle development history:
Lawrence Ellison, his friends and former colleagues Bob Miner and Ed Oates set up the Software Development Laboratory (SDL) in 1977.
SDL developed the first version of Oracle Bone Inscriptions software. Oracle Bone Inscriptions's name comes from the code name of a project created by the Central Intelligence Agency in which Ellison worked at Ampex.
Refer to the above content: Baidu Encyclopedia -Oracle Database