Conventionally, an information storage medium such as a memory card or optical recording disk capable of saving information is detachably installed in a digital still camera or digital video camera.
Information saved in such an information storage medium is electronic data such as an electronic file. The information storage medium cannot make information saved in it visible by itself. To see the information saved in the information storage medium, an apparatus such as a camera or personal computer (PC), which can read and display the information saved in the information storage medium, must be used.
Some information storage media have a display unit (label) to display, e.g., the index of saved image data or the remaining capacity of the information storage medium (e.g., Japanese Patent Laid-Open No. 2002-245747). A memory card having a rewritable display unit (label) is also available (e.g., Japanese Patent Laid-Open No. 2003-331560).
An information storage medium having such a display unit (label) visibly displays saved information. Hence, the information storage medium can make information saved in it or its remaining capacity visible by itself.
In the information storage medium having a display unit, however, when saved information contents are rewritten, and the display contents of the display unit are not rewritten, a problem is posed. That is, the information contents saved in the information storage medium do not match the display contents of the display unit. For this reason, a user who determines the information contents saved in the information storage medium on the basis of the display contents of the display unit erroneously recognizes the information contents saved in the information storage medium. That is, the information saved in the information storage medium cannot be recognized in itself.
Additionally, when the rewrite of information contents is frequently done, the display unit (label) memorized by the user does not match the display unit (label) actually displayed by the information storage medium at a high probability. Especially when one user handles a plurality of information storage media, he/she cannot identify each medium at a high probability.
Even when the information storage medium has a rewritable display unit, the display unit is invisible when the information storage medium is installed in a device. The medium is inconvenient because the user cannot identify the information storage medium currently in use.
Furthermore, even when the information storage medium has a rewritable display unit, it may be difficult for a user who uses a plurality of media to identify each medium.