Oracle Message ORA-12547 - TNS: lost contact

ERRORTNS: lost contact
CAUSEPartner has unexpectedly gone away, usually during process startup.
ACTIONInvestigate partner application for abnormal termination. On an Interchange, this can happen if the machine is overloaded.

954896ORA-12547 connecting to sqlplus / as sysdba on AIX 5L
106525Oracle processes terminates with memory problems
1568885ORA-12547: TNS:lost contact on AIX with online patches
505630Composite SAP Note ORA-12547
1055400Oracle 10.2.0.2: Work processes terminate on Windows 2003