Isolated pulse shapes and medium noise are analyzed for narrow track recording by micro-magnetic simulation. Low density recording is simulated and studied with thin film heads of widths 1.5, 1.0, and 0.5 /spl mu/m. Isolated pulse shape for a 0.5 /spl mu/m width recording is severely distorted compared with that for a wide recording. A formula for the PW50 of an isolated pulse is empirically obtained. For a fixed gap length, the first null in the spectrum shifts to lower frequency with a smaller head width. Increases in total noise power are sensitive to narrower heads, especially in the submicron region of the head width.