In the computer system where the plurality of host computers and the plurality of storage apparatuses are interconnected, in order to carry out the data migration between the storage apparatuses transparently to the host computers, the back end server provides the virtual disk to the host computers. The polymer composite membrane can have a high proton conductivity andor a reduced methanol permeability and can be used in fuel cells, electrochemical sensor, and the like. The compounds of the invention are useful in preventing and treating diseases, such as anemia, organ injury, and diseases of the central nervous system, and as an adjunct to cellular treatments, such as stem cell therapies. The wavelength of a light beam passing through the transparent substrate has been selected from the range from 400 to 420 nm. Thereby, even if the printing device does not support one of, or both of the index printing and the multiple printing, the index printing andor the multiple printing can be conducted.