Described herein are one or more implementations for reducing the effects of distortion caused by the distorters in medical image-capture components used in medical electromagnetic tracking system. In an aspect, journal bearing asymmetry is minimized or eliminated and axial span is increased between journal bearings, reducing wobble or run-out between relatively rotating components. When a read-ahead abort prevention function is provided at the host computer side, if the read ahead is interrupted by detecting an error at the disk drive side during the read ahead, the host device, after receiving an error report, causes the disk drive to resume the read ahead from the address at which the read ahead was interrupted.