Patent ID: 7904609

Claim:
A USB multi-function device connectable to a computer through a USB interface and recognized by the computer as one of a a plurality of devices comprising at least a USB storage device and an additional device different from the USB storage device, the USB multi-function device comprising: a data storage section configured to access a data storable physical storage area, and read data stored in the physical storage area or write data to the physical storage area; a file system configured to manage data to be stored in the physical storage area of the data storage section as a file, provide an interface for accessing to the file, and enable reading of data stored in the file or writing of data to the file by an access with the interface; a data processing section configured to execute a predetermined data processing, and during the data processing, access the file through the file system; a mode switching section configured to switch the USB multi-function device between a first mode in which an access from the computer to the USB storage device is permitted and a second mode in which an access from the computer to the USB storage device is prohibited; a data analysis section configured to analyze whether a data string transmitted between the computer and the additional device is a standard data string transmitted for an access to the additional device or a particular data string other than the standard data string; an additional device control section configured to, when the data analysis section analyzes that the data string is the standard data string, control the additional device on the basis of information in the standard data string; a mode determination section configured to, when a data string is transmitted between the computer and the USB storage device, determine which of the first and second modes is selected by the mode switching section; a physical area unit access section configured to, when the mode determination section determines that the USB multi-function device is switched to the first mode, access the physical storage area of the data storage section based on information in the data string transmitted from the computer to the USB storage device, and transmit a response data corresponding to the access to the computer; a pseudo response section configured to, when the mode determination section determines that the USB multi-function device is switched to the second mode, transmit a pseudo response to the computer, the pseudo response indicating that no storage medium is mounted to the data storage section; and a file unit access section configured to, when the data analysis section analyzes that the data string is the particular data string, access a file through the file system based on information in the particular data string, and transmit a response data corresponding to the access to the compute.