P.L. Garrido and G. Gallavotti Boundary Dissipation in a Driven Hard Disk System (451K, LaTeX 2e with 7 PS Figures, tar+gzip) ABSTRACT. A simulation is performed aiming at checking the existence of a well defined stationary state for a two dimensional system of driven hard disks when energy dissipation takes place at the system boundaries and no bulk impurities are present