Abstract: An alignment disk including data tracks written in a spiral configuration, through the use of microstepping techniques, to accurately test a variety of transducer head parameters including head alignment, resolution and offset. The tracks include standard spiral tracks, S-shaped clamping spiral tracks and bordered spiral tracks, comprising a sequence of discrete address blocks each containing unique identifying information. The spacing of each address block is precisely known and because each is separately identifiable transducer head location can be precisely ascertained. The microstepping technique may also be employed to create a copy protected disk for disk drives having half-track read and write capabilities.

Abstract: A multiple system data storage disk adapted for use with more than one type of computer. The disk is specially formatted to include software for each computer. The disk includes four discrete recognition headers, one for each target computer, placed at locations on the disk where each computer expects to being its data loading operation. Each header further includes software directing the computer to step out to a discrete group of data tracks located elsewhere on the disk. Each data track group contains an identical program, written in each target computer's language. The disk is suited to video games for multiple computers. An alternative embodiment of the disk includes a header or headers containing a magnetic signature for copy protection. A disk can be produced with twenty-four such headers, one for each type of computer on the market, which can be mass produced to provide low-cost copy protection for all machines.