* os.name should point to the actual os.name and not be "java". We
currently have an os._name that does this, but there are plenty of
ways to detect that we are on the JVM and so we don't need to take up
this spot with another check.
May I humbly suggest following IronPython on this?

The Python 3.3 doc says:

The name of the operating system dependent module imported. The following names have currently been registered: 'posix', 'nt', 'mac', 'os2', 'ce', 'java'.

See also

sys.platform has a finer granularity. os.uname() gives system-dependent version information.

The platform module provides detailed checks for the systemís identity.

Note that all of the names other than "java" are actually operating systems.

Iron Python (on Windows) returns os.name as 'nt'.
>>> os.name
>>> sys.platform
>>> platform.uname()
('cli', 'z-PC', '', '', '', ''
>>> platform.system()
>>> platform.platform()
>>>>>> repr(sys.implementation)
=sys.version_info(major=2, minor=7, micro=3, releaselevel='final', serial=0))"