a high density fixed head disk drive is shown . small track width and small inter - track spacing is accomplished by small head - to - media distances , which are maintained by fabricating both read / write heads and demultiplexer circuitry on a single planer substrate constituting a head mount disk . spacing between the head mount disk and media disk is controlled by placing the head mount disk on the periphery of annular housings that are slightly thicker than the media disk and thus controlling the spacing there between . close inter - track spacing is provided by angularly offsetting radial groups of read / write heads on the head mount disk . construction of a head mount disk and media disk of the same material provides physical thermal tracking thus minimizing track misalignment problems due to temperature variations . additionally , shorter duration writing pulses are employed on outer tracks to increase information density per unit area of the media disk . in an alternate embodiment , head - to - media separation is eliminated by fabricating heads that extend to make contact with an opposing media disk . contact is maintained with the media disk by angling the lash heads in the direction of media disk travel and flexing them against the same .