| 摘要 |
<p>PURPOSE:To reduce the storage quantity of a journal required to restore a file and to decrease the saving frequency of the whole file. CONSTITUTION:When the file 2 is generated, a save tape 4 is generated in advance, and a block image after file update by a process group 1 is stored in a journal tape group 6. When the journal tape group 6 is gathered, the save tape 4 is rolled forward by using a tape roll forwarding process 7 and a new save tape 4' is generated. In case of a file fault, the file is restored by using the new save tape 4' and a journal tape group 6 which is stored newly after the roll forwarding process.</p> |
