Does Sonar Disk-Stream A Duplicate Audio Track ?

Don't know, but it should be easy to find out.

Create a new project with the save preferences set to storing the audio in a per-project audio folder.

Create 1 audio track and record something into it, doesn't matter what, even just silence will do.

Create another track and copy the 1st track's audio into it.

Then save the project and take a look to see how many wave files are in the project audio folder. If 1 then the audio hasn't been duplicated, if 2 and when played back by e.g. Windows Media Player they're the same then they have been duplicated.

I'd do the test myself but am without a working PC at the moment and don't want to go through the hassle of installing Windows on a Mac just to find this out, sorry. :-)

I may not have asked the question quite detailed enough....
 
It wouldn't necessarily matter if there was 1 file or 2 files on disk, that may not give us the answer.  Let's say we clone a track inside a project, and there's not a new audio file created.  Sonar might still disk stream both tracks on playback (reading the same file).  Rather than be smart enough to know the same audio file can be read just once.  This is what I'm wondering about, and yeah it matters because if on occasion you are accustomed to taking mono tracks and cloning them for stereo imaging purposes, then you could be doubling the amount of disk I/O in the process.   

BTW I'm not sure what linked clips are, will have to look into that....
 
Sonic