An information recording apparatus according to the present invention manages a priority value for each host that can log in, and allocates an immediate data buffer to each host based on the priority value. An upward-facing base dome in each cavity supports the lenses with the rims of the lenses downward. The protrusion portion extends from the front end of the plate-like extending portion toward the outside in the seat width direction. The opposed sealing surfaces define a sealing area therebetween. The window operator includes a drive shaft retention assembly for receiving and retaining the drive shaft once the drive shaft is inserted into the drive assembly.