After upgrading from Oracle 8.1.5 to 8.1.6, and deleting SDE 8.01 and installing 8.02, starting SDE service yields this error:
Giomgr.exe - initialization of DLL E:\oracle\ora81\bin\oranro8.dll failed. The process is terminating abnormally.
This appears to be caused by a known Oracle issue (#1233351). The file oci.dll is not overwritten during an upgrade from 8.1.5 to 8.1.6.
WARNING: The instructions below include making changes to essential parts of your operating system. It is recommended that you backup your operating system and files, including the registry, before proceeding. Consult with a qualified computer systems professional, if necessary.
ESRI cannot guarantee results from incorrect modifications while following these instructions. Therefore, use caution and proceed at your own risk.
1. Navigate to ORACLE_HOME\bin.
2. Disable the oci.dll by renaming it or moving it elsewhere.
3. Copy oci.dll, dated 01/25/2000, from a clean 8.1.6 install, to ORACLE_HOME\bin. The SDE service should start fine.