Oracle Message ORA-01092 - ORACLE instance terminated. Disconnection forced

ERRORORACLE instance terminated. Disconnection forced
CAUSEThe instance this process was connected to was terminated abnormally, probably via a shutdown abort. This process was forced to disconnect from the instance.
ACTIONExamine the alert log for more details. When the instance has been restarted, retry action.

613714Oracle 9i: ORA-00600 [qctstc2o1]
636475Secondary Oracle error codes
582427Error due to inconsistent Oracle DDIC