Patent ID: 7949796

Claim:
A device that is connectable to a computer through a communication interface capable of transmitting a data string based on SCSI (Small Computer System Interface) standard, and functions as a storage device capable of being controlled by the computer according to SCSI commands defined in the SCSI standard, the 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, when several kinds of commands previously selected from among the SCSI commands are defined as particular SCSI commands, and other commands than the particular SCSI commands are defined as standard SCSI commands, switch the device to one of a first mode in which an access to the storage device with the standard SCSI commands is permitted and a second mode in which an access to the storage device with the standard SCSI commands is prohibited; a data analysis section configured to, when an SCSI command from the computer is transmitted through a logical data transmission line between the computer and the storage device, analyze whether the SCSI command is a standard SCSI command or a particular SCSI command; a mode determination section configured to, when the data analysis section analyzes that the SCSI command is a standard SCSI command, 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 device is switched to the first mode, accesses the physical storage area of the data storage section on the basis of the SCSI command, and transmits response data corresponding to the access to the computer through the data transmission line; a pseudo response section configured to, when the mode determination section determines that the device is switched to the second mode, transmit a pseudo response to the computer through the data transmission line, 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 SCSI command is a particular SCSI command, access the file through the file system on the basis of the particular SCSI command, and transmit response data corresponding to the access to the computer through the data transmission line.