A method and machine to allow for the spark-erosion machining of parts, in particular their finishing, using cylindrical or tubular tools by successive layers. The edge stiffener may be coupled to leads of the lead-frame for providing electrical contacts at the periphery of the circuit module or may be form widened portions of a tie bar that is connected to the lead frame by leads extending through gaps between the ends of the edge stiffener portions. A method and system of the present invention includes an establishment of quotas for an area of a file system that takes into account the belonging of a file to a certain subtree or subtrees of the file system.