Long description

The figure shows three disks divided into 31 segments.

Figure a: The segments are labeled 0 to 29 from the top in a clockwise direction. The seventh segment is left empty and shaded in dark and labeled bad sector. Segments 30 and 31 are also left empty and shaded in a light color and labeled space sector.

Figure b: The segments are labeled 0 to 29 from the top in a clockwise direction. The seventh segment is left empty and shaded in dark. Segments 30 is labeled 7 and segment 31 is left empty and shaded in a light color.

Figure c: The segments are labeled from the top in a clockwise direction as follows, 0 to 6, then blank, 7 to 29, then blank. The first blank segment is shaded in dark color and the second blank segment is shaded in a light color.