Hard-disk drives are the most popular storage devices in modern PCs. Recently, for higher speed and higher capacity, the accurate positioning operation of read/write magnetic heads becomes required. As the inside flow often causes pressure and velocity fluctuations, more accurate research have been needed. Our present interest is the flow between two disks. Namely, we consider a pair of disks of the same radius in a stationary cylindrical enclosure. Disks are connected with a common shaft, and corotate. Such a flow is often non-axisymmetric, and consists of two regions, that is, the region in solid-body rotation and the region of secondary flow. Until now, various studies have been carried out in order to resolve the flow. The authors attempt flow and thermo visualizations on a real HDD. Thermo visualizations show no obvious increase of disk-surface temperature during first 60[min.]. We confirm the existence of the solid-rotation core with some obstructed flows. But, there is no core at higher brockage ratio of the obstruction.