Adjusting power states for improved device performance

A method of controlling an electronic apparatus that operates in a normal mode and a power-saving mode, a smaller amount of electricity being consumed in the power-saving mode than in the normal mode, the electronic apparatus including a connection interface to which a reader that reads information from an external storage medium is connectable, the method comprising:

• when the electronic apparatus transits from the normal mode to the power-saving mode, causing the electronic apparatus to transit to a first power-saving mode if the reader is connected to the connection interface or to a second power-saving mode if the reader is not connected to the connection interface,
• wherein both the connection interface and the reader are operable in the first power-saving mode,
• wherein a lower amount of electricity is consumed in the second power-saving mode than in the first power-saving mode, and
• wherein before the electronic apparatus transits from the normal mode to the first power-saving mode or the second power-saving mode, the electronic apparatus transits to a fourth power-saving mode in which a lower amount of electricity is consumed than in the normal mode and in which a larger amount of electricity is consumed than in the first power-saving mode, and then determines whether the reader is connected to the connection interface.