I am a PhD (stipend) student at a Max Planck Institute (for a biological science) here in Germany. I came here to write software, but ended up spending practically all my time doing wet-lab work. As a consequence, the programming I wanted to do had to be done in the evenings outside of the institute (although what constitutes 'PhD time' and 'programming time' is a bit of a blur, since I use my programs to solve PhD problems...)
Coming to the end of the PhD, I am now finally ready to "publish" the first of the three programs I have written during my time here in Germany, but there are three stakeholders all with competing interests in my software which make it difficult for me to know how to proceed...
The Max Planck - they will want to claim ownership of the software, because I wrote it while doing a PhD with them. Over the course of the PhD, no one from the Max Plank or the University have had any input whatsoever on the software, however, certainly between 10-20% of the code was developed 'on PhD time'.
The Journals - publishing is not a requirement, but it would be nice. It forms a stamp of approval (in some people's minds) and acts as free advertising at the very least. But for this to happen, I suppose I cannot "publish" my code already, meaning open source it and share it so people can bug-check it before publication?
The Users - Arguably the most important stakeholder for me, because I wrote this software for them. I want to make the code's licence as permissive as legally possible, probably under Creative Commons Zero to aid with this, but I feel this will make publishing impossible, and it may not even be allowed if I am not the owner of the copyright in the first place.
How should I proceed?