Hi GE Osmonics,
Multiple versions of the LabWindows/CVI development environment can be installed on the same system. In your case, you can have both CVI 6.0 and CVI 8.0 installed on the same machine. One thing to mention here is that you will only have one version of the CVI Run-time engine installed on the system, regardless of how many different versions of the CVI development environment you have installed. This is because the CVI installer removes old CVI Run-time engines when a newer one is installed on the machine. All of your CVI programs will use the latest CVI Run-time engine, which is backwards compatible.
Hope this helps!
Best Regards,
Jonathan N.
National Instruments