Disclosed are a method and apparatus, in a data storage environment with multiple devices sharing data, for writing data to one such device in a manner that indicates that the data need not be destaged to a lower tier of the storage hierarchy. Rollers, which have a greaseless bearing structure and are provided on support shafts of the vane, are rollably engaged with annular channels of a casing so as to interconvert reciprocation of the pistons and rotational movement of the rotor. The I-picture data may be divided into fraction according to the position on the screen, the DCT frequency, or layering, and the fractional I-picture data may be arranged in the image information blocks, and a header or parity signal is recorded in front of each fractional I-picture data. When placed upon a pallet for loading, the central panel fits atop the pallet, and the four side flaps extend outward. The upgraded systems comprise an optical data loop of a plurality of destination terminals and a single intermediate terminal.