As grids become more and more attractive for solving complex problems with high computational and storage requirements, the need for adequate grid programming models is considerable. To this purpose, the GridRP C model has been proposed as a grid version of the classical RPC paradigm, with the goal to build NES (Network-Enabled Server) environments. In this model, data management has not been defined and is now explicitly left at the user's charge. The contribution of this paper is to enhance data management in NES by introducing a transparent data access model, available through the concept of grid data-sharing service. Data management is totally delegated to the service, whereas the applications simply access shared data via global identifiers. We illustrate our approach using the DIET GridRP C middleware and the J UXME M data-sharing service. Notably, our experiments performed on the Grid'5000 using a real-life application show the efficiency of using JuxMem for managing persistent data in the GridRPC model: application execution times in a grid environment are of the same order as in a cluster environment.