A lower portion has a lower end and an upper end. Mirror housing 2 includes concave part 2C formed in an opening manner downwardly which is arranged in the vicinity of photographing window 2B where lens 5B of the camera main body part 5A is faced, and capable of accommodating an illumination light source. The plurality of data placement optimizers are each configured to analyze the system configuration data and the system performance data for developing a corresponding data movement plan. An arm carrying a shoe extended outside the strands of chain and positioned to contact an outside portion of chain is pivotally mounted to the fixed pin. The host may push the variables onto the stack and the TOE may pull the variables from the stack. The temperature or the dew point is measured in the environment of the place where, when cool drying, the temperature of the gas to be dried is the lowest.