Abstract: A digital business card has a rectangular substrate and a magnetic stripe. The substrate has a printing surface disposed on a surface of the substrate for printing visual data, and a photo-recording region disposed on the rear of the substrate for storing digital data. The magnetic stripe is disposed on the surface of the substrate adjacent to a short side of the substrate for recording magnetic recording data and storing a specific encoded password. The digital business card effectively controls reading data in the digital business card through the combination of the magnetic stripe and the photo-recording region so as to prevent the data from being stolen. Besides, the digital business card has the same size as a conventional printed business card, so that the digital business card is carried handily and has high capacity of storing data.

Abstract: An apparent data erasure method for an optical disk. The content of a first data content table and the content of a second data content table are stored in the boot region of the optical disk. By removing the data in the a second data content table from the data in the a first data table, only a portion of the data in the data-recording region of the optical disk is displayed.

Abstract: A digital data vending machine suitable for downloading digital data to a user after a payment and allowing a service provider to update digital data at any convenient time. The user uses the input controller to select digital data content. Thereafter, the fee-charging device is activated under the supervision of the central processing unit. The requested digital data are permitted to be transferred from the data storage device to the data input/output device, ready for the user to download when proper fees are paid. The service provider also uses the input controller to select the digital data content to be updated. After selection, external data is transferred from the data input/output device to the data storage device under the supervision of the central processing unit.

Abstract: A digital business card has a rectangular substrate and a magnetic stripe. The substrate has a printing surface disposed on a surface of the substrate for printing visual data, and a photo-recording region disposed on the rear of the substrate for storing digital data. The magnetic stripe is disposed on the surface of the substrate adjacent to a short side of the substrate for recording magnetic recording data and storing a specific encoded password. The digital business card effectively controls reading data in the digital business card through the combination of the magnetic stripe and the photo-recording region so as to prevent the data from being stolen. Besides, the digital business card has the same size as a conventional printed business card, so that the digital business card is carried handily and has high capacity of storing data.