IMPORTANT: Conflicts between Application Versions
If an application is available both for 32-bit and 64-bit environments, parallel installation of both versions is bound to lead to problems. In such cases, decide on one of the two versions and install and use this.
To be executed correctly, every application requires a range of libraries. Unfortunately, the names for the 32-bit and 64-bit versions of these libraries are identical. They must be differentiated from each other in another way.
To retain compatibility with the 32-bit version, the libraries are stored at the same place in the system as in the 32-bit environment. The 32-bit version of libc.so.6 is located under /lib/libc.so.6 in both the 32-bit and 64-bit environments.
All 64-bit libraries and object files are located in directories called lib64. The 64-bit object files you would normally expect to find under /lib, and /usr/lib are now found under /lib64, and /usr/lib64. This means that there is space for the 32-bit libraries under /lib and /usr/lib, so the filename for both versions can remain unchanged.
Subdirectories of 32-bit /lib directories whose data content does not depend on the word size are not moved. This scheme conforms to LSB (Linux Standards Base) and FHS (File System Hierarchy Standard).