a tool such as a profilometer the acquired surface irregularity information may used by a computer to provide a correction function or a series of correction factors as shown in fig5 d in one embodiment the interior of the calibration standard 100 is protected from contaminants by an enclosure 70 in one embodiment the enclosure 70 is secured to fixtures 81 82 by attaching means such as screws 91 92 in this embodiment the fixtures 81 82 are secured to the mock disc by a material such as an adhesive in one embodiment the mock slider 50 contacts the mock disc 10 via the beams 52 53 54 the mock slider 50 is held to the mock disc 10 by the spring force pre loaded bend of the suspension arm 40 amount of force necessary to maintain contact as illustrated in fig5 d in one embodiment three support bumps 42 43 44 of substantially the same height are located on the suspension arm 40 in this embodiment each support bump 42 43 44 is located directly below a respective bracing beam 52 53 54 on the mock slider 50 in one embodiment the suspension arm 40 has two locating pins 45 46 which are utilized to maintain the mock slider 39 s 50 position upon the suspension arm 40 in one embodiment the locating pins 45 46 are shorter come to a point lower than the surface of the mock slider 50 upon.