Storage system with a data sort function

A storage system, connectable via a communication channel to one or more host devices, comprising an external storage device having one or more physical devices to store data for input from and output to said host devices and a storage control device which controls transfer of said data between said host devices and said external storage device, wherein:

• said storage control device has cache memory which temporarily holds one or more blocks of said data, control information memory which stores control information, and a control portion which is connected to said host devices, said external storage device, said cache memory, and said control information memory, defines each of one or more sets of blocks of said data stored in said external storage device as one or more logical devices, and controls the input and output of said blocks to and from said external storage device, said cache memory, and said host devices;
• said control portion has one or more processors which receive sort processing execution instructions from said host devices and perform sort processing;
• said one or more processors are notified, by means of said sort processing execution instructions, of sort-in information specifying an arbitrary block group within an arbitrary logical device as a sort-in block group, key information specifying data at an arbitrary position in said blocks as a sort key, sort-work information specifying an arbitrary block group in an arbitrary logical device as a sort-work block group, and sort-out information specifying an arbitrary block group in an arbitrary logical device as a sort-out block group;
• and,
• said one or more processors, when executing said sort processing in response to said sort processing execution instructions, write said specified sort-in block group in said external storage device to said cache memory, and while using said specified sort-work block group as a work area, sort said specified sort-in block group written to said cache memory based on said specified sort key, store said sorted sort-in block group to said specified sort-out block group, and notify said host devices of the completion of said sort processing.