In addition, tracks did not need to be perfect rings, but could be sectioned so that sectors could be staggered across overlapping offset tracks, the most extreme version being known as spiral tracking. This allowed complex disk-based software copy protection, by storing data on half tracks (0, 1, 2.5, 3.5, 5, 6.), quarter tracks (0, 1, 2.25, 3.75, 5, 6.), and any combination thereof. On the Apple II, unlike modern computers that use standardized device drivers to manage device communications, the operating system directly controlled the step motor that moves the floppy drive head, and also directly interpreted the raw data, called nibbles, read from each track to identify the data sectors.
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