| 摘要 |
PURPOSE:To attain the repetitive use of a floppy disk and at the same time to prevent assuredly the data destruction within a protection period, by attaining the control of number of days for the written contents of the floppy disk. CONSTITUTION:A control part for number of days is provided in a control area CTL of a floppy disk, and the number of recorded days and the store address are recorded for each data within a data protection period with corresponding data 1, 2, 3 are written. It is checked whether a blank space exists at first, before new data are written. If no blank space is available, the presence or absence is chekced for the data with which the protection period elapsed. If such data does not exist, the writing is inhibited. In case of 1, for instance, that passed the protection period exists, it is judged that 1 is not needed. Then the final end of 1 is defined as an end point EP, and 1 is opened and the writing is carried out over the 1. This ensures the effective use of the floppy disk and at the same time prevents the destruction of data. |
