| 摘要 |
PURPOSE:To prevent the outsiders from copying files and to enable a person who performed the writing jobs to restore the files by dividing physically a subject file to write these divided files into the random idle areas of a subject writing disk and defining hereafter these idle areas as the inhibited areas for use. CONSTITUTION:All idle sector numbers of a writing disk 1 are checked (by checking a file allocation table FAT2). Then the random numbers including zero through the maximum sector number, e.g., 10000 is generates. If an obtained random number is included in a group of said sector numbers, the random number is written into the corresponding sector number. In case the obtained random number s not included in the sector number group, the next random number is acquired and the same operation is repeated. Then a 'use inhibiting mark' received from an operating system OS is written into an area of the FAT2 corresponding to the written sector number. Thus the outsiders can never detect the relevant sector number and the person who wrote it can restore the corresponding file in a comparatively easy way. |
