In conventional image reading in a large-sized scanner using plural CIS sensors, overall linearity of an original is poor, and a shift occurs particularly at connection portions of the CIS sensors in the read image. A second similar isolation stage may be coupled to the first isolation stage, and a third similar isolation stage may be coupled to the second isolation stage. To that end, one portion of the disk array is organized into a home location array having a set of sequential home locations for disk blocks.