The jrk's graphical configuration utility only works in Windows, but there are other ways to configure the device. I think David's post
on the Pololu forum explains this better than I could (he is one of the primary engineers behind the jrk):
We don't distribute precompiled Jrk software for Linux, but you can download the Pololu USB SDK
and compile JrkCmd, a command-line utility (written in C#) for configuring and controlling the jrk. You can use JrkCmd to configure the jrk from a configuration file (which you can get from either JrkCmd or the Jrk Configuration Utility).
The complete documentation of the jrk's serial protocol is in the user's guide
, but the permanent configuration settings of the jrk can only be changed over USB using control transfers. For more information on what control transfers the jrk supports and what the protocol is for them, you can see the source code of the Jrk class in the Pololu USB SDK; that source code could be considered advanced documentation for the jrk. However, if all you want to do is configure the jrk from the command line, you won't need to look at the source code because JrkCmd supports that already.
As for Mac OS: we haven't tried compiling any of the jrk software for Mac OS and can't really support it, but you might be able to get it to work because both mono and libusb work on the Mac.
Note that the all of the jrk's settings are stored in non-volatile memory, so one option is just to find a Windows machine and use the graphical utility when you want to reconfigure the jrk, which probably won't be very often once you have it set up for a particular application.
Does this adequately address your questions?