Abstract: A method and apparatus for checking performance and alignment of a disk drive designed for use with a floppy disk having a motor driven linear positioning mechanism for locating the read/write transducer over the diskette circular tracks. A digitally prerecorded diagnostic diskette has a series of precisely located special diagnostic tracks providing reference data for various alignment and response characteristics, both mechanical and electronic. A first group of tracks have sector ID blocks followed by progressively offset data blocks interspersed therein, with the range of the offset greater than the width of the track for which the disk drive is designed, which guarantees a read failure upon reading any track. These tracks are distributed radially across the surface of the diskette at positions corresponding to each rotational phase position of the transducer stepper motor.