PRIMA is an implementation of the Globus authorization callout. This callout allows the default Globus grid-mapfile to be overridden by a software implementation. In the VDT, GUMS is an alternative to the Globus grid-mapfile, but Globus does not know how to contact GUMS without a third-party callout. The PRIMA software is this third-party callout and it allows a connection between Globus and GUMS so that GUMS is used instead of the grid-mapfile.
There are two versions of PRIMA, one for Globus pre-web services, and one for Globus web services. The pre-web services implementation works for both pre-web services GRAM and GridFTP. The web-services implementation works for web services GRAM. Both of these versions of PRIMA are in the VDT.