In particular, this technique allows heterogeneous coupling. In the SIPC technique, using UNIX System V Inter Process Communication possibilities, the synchronization is ensured by semaphores and shared memory segments are used to exchange the coupling fields. The GMEM technique works similarly as the SIPC one but is based on the NEC global memory concept. These transformations, or analyses, can be different for the different fields. Then follows the interpolation of the fields required to go from one model grid to the other model grid.
Additional transformations ensuring for example field conservation occur afterwards if required.
Finally the post-processing puts the fields into the receiving model format. Quite clearly, the only way to handle this heterogeneous environment was to create a very modular and flexible tool. The first version of the software, Version 0, was used in the forcing of an oceanic GCM by a set of atmospheric fluxes issued from an AMIP-type run. Version 1.1, released in 1994, incorporated several new features. Version 2.0 was a major rewriting of the software as the goal was much more ambitious.