dbrower's response seems to relate to my question. Here's my story:
I work in a large enterprise that runs several Oracle based applications. All apps must peacefully co-exist on a single NT 4.0 PC workstation. All PC based Oracle clients access a shared Oracle home located on a network drive. (i.e. All Oracle apps on the PC are configured to look at a single NT registry key Oracle_Home = X that defines the network directory in which all Oracle client components are stored.) Presently, applications using Oracle client versions 7.x and 8.X are running off the shared Oracle home. A new application running 8i is to soon come on line. My task is to upgrade the shared Oracle home in such a fashion as to add function of the 8i client while retaining function of the 7.x and 8.x clients.
I first attempted to "upgrade" the shared home by directing the 8i installation program to install into the directory that holds the 7.x and 8.x components. This attempt failed because I "attempted to install into an Oracle home that was created with an older, incompatible version of the Oracle installer." OK. That seems straight forward. It doesn't work that way- I'll try something else.
I then installed all 8i components into a separate directory and replaced the older shared home.
I wound up with an 8i home out of which I can successfully tnsping all databases, 7.x, 8.x and 8i Oracle versions. An application requiring an 8i client connects to its database and runs properly. However, an application running Oracle version 18.104.22.168.1 cannot connect its database. The failing app returned Oracle error ORA-12154.
I am under the impression that 8i is backward compatible and should support the earlier Oracle client versions. Am I wrong on that? Is there some specific manner in which I should build an 8i home that will also support the earlier Oracle clients? Any other suggestions?
Thanks for considering this question,