Hi Mariano, On May 16, 2017, at 6:35 AM, Mariano Martinez Peck <marianopeck@gmail.com> wrote: Guys, As you know, OSSubprocess does not work correctly in Linux unless you use the iTimer VM. As others have pointed out, you mean that OSSubprocess does not work correctly unless you use the threaded heartbeat VM. That the itinerary heartbeat breaks OSSubprocess. I would like to open a warning (that growl thingy on bottom left of the screen) or something at loading / install time if I can detect I am under Linux AND under traditional linux VM (not itimer). Do you know how can I do that? I made a mistake in that there is no way, other than by using the FFI, to discover if the timer heartbeat is being used. Would it be satisfactory if I provide a flag in vm parameter 48 that, if set, indicates the itimer heartbeat is in use? This could be done in a few minutes and would be ready for the official release of Pharo 6. -- Mariano http://marianopeck.wordpress.com