| 摘要 |
<p>An external storage using nonvolatile semiconductor memory, such as flash memory, includes a plurality of areas for storing user data. To facilitate using the external memory for the host computer, the access to the user data from the host computer is controlled while dynamically changing the areas where access control takes place. Specifically, the flash memory is divided to provide ordinary areas and password protection areas. A microprocessor controls the access to the ordinary areas and the protection areas depending on a command from the host computer. The protection areas are accessible after password authentication. The information indicative of the position of the protection areas is changed by the host computer to change the protection areas dynamically.</p> |
