IC card and OS activation method for the same

An OS activation method for an IC card capable of sending/receiving data by a plurality of data transfer methods and including a plurality of OSs respectively corresponding to said plurality of data transfer methods, comprising:

• an OS activating step of activating one of said plurality of OSs when power is supplied to said IC card;
• a transfer method determining step of determining, on the basis of an externally received data, which of said plurality of transfer methods is employed for data transfer with an external device;
• an OS applicability determining step of determining whether or not a first data transfer method out of said plurality of data transfer methods corresponding to said OS activated in the OS activating step accords with a second data transfer method determined in the transfer method determining step;
• and
• an OS switching step of switching said OS activated in the OS activating step to another OS out of said plurality of OSs when it is determined that said first data transfer method does not accord with said second data transfer method in the OS applicability determining step.