Storage device, access control device and electronic apparatus

An access control device, comprising:

• a command receiving section that receives a command including designation of an access point within a storage area where data is stored and designation of data access to the access point, the command receiving section being capable of accepting designation of a point in a visible area defined within the storage area as the access point, while being incapable of accepting designation of a point in an invisible area except for the visible area as the access point;
• a command distinguishing section that distinguishes whether the command received by the command receiving section is a within-protection command that designates an access point within a protected area defined in the visible area or an off-protection command that designates an access point outside the protected area in the visible area;
• an off-protection command control section that causes an access section that performs data access to the storage area to perform data access to the access point designated by the off-protection command;
• a within-protection writing control section that causes, when data writing is designated as the data access by the within-protection command, the access section to write data at an alternative point in the invisible area, and records a correspondence between the access point designated by the within-protection command and the alternative point;
• and
• a within-protection reading control section that searches for and finds, when data reading is designated as the data access by the within-protection command, the alternative point corresponding to the access point designated by the within-protection command based on the recorded correspondence, and causes the access section to read data from the found alternative point.

An electronic apparatus, comprising:

• an information processing section that executes information processing according to program data stored in a storage area where data is stored, and issues, during information processing, a command including designation of an access point within the storage area and designation of data access to the access point;
• an access section that performs data access to the storage area;
• a command receiving section that receives the command issued by the information processing section, and the command receiving section being capable of accepting designation of a point in a visible area defined within the storage area as the access point, while being incapable of accepting designation of a point in an invisible area except for the visible area as the access point;
• a command distinguishing section that distinguishes whether the command received by the command receiving section is a within-protection command that designates an access point within a protected area defined in the visible area or an off-protection command that designates an access point outside the protected area in the visible area;
• an off-protection command control section that causes the access section to perform data access to the access point designated by the off-protection command;
• a within-protection writing control section that causes, when data writing is designated as the data access by the within-protection command, the access section to write data at an alternative point in the invisible area, and records a correspondence between the access point designated by the within-protection command and the alternative point;
• and a within-protection reading control section that searches for and finds, when data reading is designated as the data access by the within-protection command, the alternative point corresponding to the access point designated by the within-protection command based on the recorded correspondence, and causes the access section to read data from the found alternative point.