^ Custom controller with unique track layout. [1] ^ 16 sector filesystems require a compatible disk controller (PROM update) and Apple DOS 3.3 or later. 1⁄2-inch (90 mm) drives use variable sectors sizes (tracks 00-15: 12 sectors, tracks 16-31: 11 sectors, tracks 32-47: 10 sectors, tracks 48-63: 9 s...