ORA-07445

[shuan.tay\(PCI鄭祺勛\)]

Dear all DBAs,   What is this error suppose to mean? $oerr ora 07445  Cause: An OS exception occurred which should result in the creation of a core file.         This is an internal error.  Action: Contact your customer support representative.   and $oerr ora 1242  Cause: The database is in NOARCHIVELOG mode and a database file was detected as         inaccessible due to media failure.  Action: Restore accessibility to the file mentioned in the error stack and restart          the instance.   What should i do and prevent the error mentioned above?   Thanks in advance.