| 摘要 |
PURPOSE:To realize a data changing system for a file on a magnetic tape processable in a short time, by providing a plurality of erasing areas with a prescribed scale at the poststage of a file data storage area. CONSTITUTION:When a data block B2 is required to change, a central processor CC3 controls a magnetic tape controller 4. Data blocks B1-B4 of a file F1 are read on a magnetic tape 2 and a specified change is done for the block B2. The block is stored in the storage area of the blocks B1-B4 before the revision on the tape 2 together with the blocks B1, B3 and B4 unnecessary for change as blocks B1'-B4' after the revision, and an erasing area R1' is stored. As a result, the change in the storage location and residual data due to the recording accuracy of the controller 4 for the blocks B1'-B4' after the revision can be absorbed with erasing areas R1, R2 set at the file forming and with the erasing area R1' set at the revision. |
