os.arch "amd64" or "x86_64"?

[Michael McMahon]

Following from the last message, I just want to get opinions on this 
question.
Currently, the os.arch system property is set to "amd64" in common with the
other platforms (solaris, windows and Linux) when running on an 
amd64/x86_64 CPU.
However, the property is set to "x86_64" in Apple's Java 6 runtime.

So, the question is, what/if any compatibility issues could there be, if 
we maintain
this behavior? On the other hand there probably should be a good reason 
to change it
so it's different from the other 64 bit platforms.

Thanks,
Michael.