ORA-07445: exception encountered: core dump [ksemgm()+320] [SIGBUS] error

I am getting the following error in the alert log.
Wed Jun 2 15:15:31 2004
Errors in file /oracle/OR09/udump/OR09_ora_27898.trc:
ORA-07445: exception encountered: core dump [ksemgm()+320] [SIGBUS] [unknown code] [0x000000000] [] []
Wed Jun 2 15:15:52 2004
Errors in file /oracle/OR09/udump/OR09_ora_27916.trc:
ORA-00600: internal error code, arguments: [12333], [16], [0], [70], [], [], [], []
Wed Jun 2 15:16:13 2004
Errors in file /oracle/OR09/udump/OR09_ora_27943.trc:
ORA-07445: exception encountered: core dump [ksemgm()+320] [SIGBUS] [unknown code] [0x000000000] [] []
Wed Jun 2 15:16:34 2004
Errors in file /oracle/OR09/udump/OR09_ora_27997.trc:
ORA-07445: exception encountered: core dump [ksemgm()+320] [SIGBUS] [unknown code] [0x000000000] [] []

What would one look for when Oracle says 'SIGBUS' or 'ksemgm'?
I have searched metalink for these 2 keywords but have not been able to find much.

Your input is highly appreciated,
Chintzs

The normal course of action with an ORA-00600 or ORA-07445 is search on MetaLink for bugs, and if that reveals nothing, open up a TAR.