| 摘要 |
PURPOSE:To minimize the number of I/O operations and the extent of movement of a disc head which are required for the final record detection, by setting the number of records in a group to a square root of the number of all records in a data set. CONSTITUTION:In an on-line system, journal information which stores operation conditions is outputted to a non-volatile external storage device such as a magnetic disc or the like to prepare for interruption of the processing due to troubles such as power break etc. A journal management program adds preliminarily sequential ascending numbers to individual journal records and outputs them to the external recording device. When the processing is restarted, the journal management program obtains the number of all records included in the journal data set and calculates a square root of this value. Records whose number is this square root are defined as one group, and only the first or the last records of individual groups are read, and their sequential numbers are compared with one another.
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