Trail Making Test: Manual for Administration and Scoring
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A magnetic head drum includes an upper section that carries a set of magnetic heads and rotates at a preselected head speed, and a stationary lower section that is characterized by a reduced diameter step formed along the tape wrap path thereover (e.g., a helical path for a helical scan recorder). Because of the reduced diameter step, tape pressure is shifted from the lower drum section to the upper drum section which, by virtue of its rotation, produces a low friction air bearing. The reduction in diameter to produce the above-described step, moreover, results in a shoulder or ledge along the lower edge of the tape wrap path, which shoulder serves as a guide for the tape, and promotes accurate tape tracking over the drum.