After some additional reading, it appears that the linux community started working and then stopped. From wikipedia and zaraxtrem.org site, there have been no updates in the past 2 years or so. Note that per wikipedia, Zara still has a nightly build for linux, but I could not find any info on it from the zara site. Also of note is that the rendering engine was NOT included in the Open Source code, so that part of the code was written by someone in the FOS community at some point. I expect that this means that the linux version is not as fast windows version.