An oxyfuel boiler system, comprising: an oxygen generator to separate oxygen from air; a coal supply unit to dry and pulverize coal; a burner having a fuel feed path for feeding pulverized coal supplied from the coal supply unit and an oxidizer feed path for feeding oxidizer; a boiler provided with the burner; an exhaust gas discharge line to discharge exhaust gas generated in the boiler into environment; an exhaust gas treatment apparatus provided in the exhaust gas discharge line, a CO.sub.2 separator provided downstream of the exhaust gas treatment apparatus in the exhaust gas discharge line to separate CO.sub.2 from the exhaust gas; an exhaust gas recirculation line including an exhaust gas tapping port provided in the exhaust gas discharge line to extract a part of the exhaust gas; and an oxygen supply line to supply the oxygen generated at the oxygen generator to the exhaust gas flowing through the exhaust gas recirculation line, wherein the exhaust gas treatment apparatus is provided with at least an SO.sub.3 removing unit and a moisture removing unit; and the exhaust gas tapping port of the exhaust gas recirculation line is disposed downstream of the exhaust gas treatment apparatus and upstream of the CO.sub.2 separator for recirculating a part of the gas extracted from the port to the coal supply unit and/or the boiler.

This storage system has an allocation unit for allocating a storage extent in prescribed units to the dynamic logical volume upon storing the data sent from the host computer in the dynamic logical volume; a management unit for managing the storage extent recognized as being currently used by the file system among the storage extents allocated to the dynamic logical volume by the allocation unit; and a release unit for releasing the storage extent that is not being managed by the management unit from the dynamic logical volume.

A storage controller calculates an access frequency of each logical disk; that is selects a first logical disk device of which the access frequency exceeds a first predetermined value, the first logical disk device being allocated to a first physical disk device; selects a second logical disk device which has the access frequency equal to or less than a second predetermined value, the second logical disk device being allocated to a second physical disk device; and reallocates the first and second logical device; and reallocates the first and second logical devices to the second and the first physical disk device, respectively.

A processor bus linked with at least a processor, a memory bus linked with a main memory, and a system bus linked with at least an input/output device are connected to a three-way connection control system. The control system includes a bus-memory connection controller connected to address buses and control buses respectively of the processor, memory, and system buses to transfer address and control signals therebetween. The control system further includes a data path switch connected to data buses respectively of the processor, memory, and system buses to transfer data via the data buses therebetween depending on t

There is provided with a cylinder apparatus comprising: a cylinder; a piston; a piston rod, one end of which is connected to the piston and the other end of which is extended outside; an external cylinder provided at an outer periphery of the cylinder so as to form a reservoir in which to seal the hydraulic liquid and gas therebetween; a base valve dividing the second chamber and the reservoir; a first check valve provided with the piston so as to allow flow of the hydraulic liquid only from the second chamber side to the first chamber side; a second check valve provided with the base valve so as to allow flow of the hydraulic liquid only from the reservoir side to the second chamber side; a flow passage connecting the first chamber with the reservoir; and an opening and closing valve opening and closing the flow passage.