Tom,
With a PXI-8175 controller, Windows 2000 and the LabVIEW RTOS are supported. You might be successful with a third party OS, but we have only fully tested the systems with the operating systems that they can ship with (Windows 2000/NT/98 or LabVIEW RTOS). The issue will be to make sure that you have the appropriate drivers.
We have NI-DAQ drivers for DOS, Windows, our LAbVIEW RTOS, and Macintosh. See the Drivers and Updates page: http://digital.ni.com/softlib.nsf/MainPage?ReadForm&node=132010_US
People use NI hardware all the time without LAbVIEW Real-Time. If you don't need deterministic real-time processing, then using C/C++ in Windows with NI-DAQ is just fine. You may want to consider using
Measurement Studio to make things easier.
Third party software vendors have been known to write register level programs to control NI hardware (not very fun).
If you want real-time response, Windows can't guarantee it, so that is why LabVIEW Real-Time was developed. Do you really need real-time performance, or is Windows adequate for you? Which other RTOS did you want to use?
Regards,
Chad H.
Applications Engineering
National Instruments
http://www.ni.com/ask