Does anyone know of a way to force StarCD to write a .pst file from within a user routine? I'm hoping for a simple call in POSDAT that can be used to override/supplement the normal fixed-frequency writes. Why? Because I want to be able to make StarCD respond to external triggers.

Maybe as an alternative you could do a system call to "mv star.pst star.`date --iso-8601`.pst" everytime posdat.f receives that trigger signal. This way, you can preserve the .pst file you want at that certain time step. But, you'll have to save a .pst file almost every iteration for this to work...