Zone 1 (21 sectors per track): tracks 1-21 (maximum density 4702bpi) Zone 2 (19 sectors per track): tracks 22-28 (maximum density 4694bpi) Zone 3 (18 sectors per track): tracks 29-35 (maximum density 4738bpi) Zone 4 (17 sectors per track): tracks 36-40 (maximum density 4716bpi) 764 non-directory track sectors per side