Abstract: A reliable, fast, easily operated system for enabling the use of both sides of existing single-sided floppy diskette units involving creation of new disk-positioning (DP) holes centered at a pre-set location, so that the new holes bear the same spacial relationship to the disk-access slot on one side of the unit the original DP holes do to the disk access slot on the other side of the unit; the system includes a DP punch comprising a plunger and plate spaced from and cooperating with the plunger, and a positioning matrix to center the DP punch plunger over the appropriate pre-set location; the positioning matrix comprises a flat top section and a flat bottom section, which are joined along a portion of their perimeters to define a slot of sufficient length, depth and width to receive said unit therebetween; one edge of the top section defines a notch adapted to receive the disk-positioning punch, and the slot and notch are located, sized and shaped so that when the unit and a punch are fully inserted into the