| 摘要 |
PURPOSE:To contrive the shortening of the time for detecting an unused block, by providing a file for recording an unused block to which use information by some large block unit has been added, in addition to a flag bit for showing an unused state provided by a block unit on a disk file. CONSTITUTION:By inspecting a file 7 for recording an unused file descriptor 6, the unused file descriptor 6 is searched, and subsequently, by inspecting a file 8 for recording an unused block, the position of the unused block is is detected. Next, its detected position is recorded in the file descriptor 6, and also, the contents of the file 8 are updated, and a novel data is written in the block being in a position where a data has been detected. In this case, the procedure for detecting the unused file 8 becomes as follows. First of all, by inspecting a byte 11 for showing the number of blocks being in an available state, whether a block of some unit is idle or not is checked, and if it is idle, which block it is checked by a flag bit 9, and the position of an unused block can be known.
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