External storage device and method for data saving, data backup

A data saving, data backup method operates in an information processing system including a first external storage device (20), a host device (1,4) which performs data input and/or output operations to/from the first external storage device and a second external storage device (30). A connection (14) is formed between the first external storage device and the second external storage device. The second external storage device is not connected to the host device. An operation is performed of automatically saving data from the first external storage into the second external storage device via the connection formed therebetween. The saving is performed based on configuration information stored in the first external storage device. The configuration information includes information for designating an execution start time of saving data to the second external storage device, and a data storing area and/or a data set name in the second external storage device at which stored data is to be stored and information for indicating at least one type of second external storage device.