| 摘要 |
PURPOSE:To reduce a history quantity by comparing a generated history record with another history records, judging whether or not the history quantity is reduced when the both are combined, and combining the both only when the history quantity can be reduced. CONSTITUTION:A history record comparing means 6 compares the history record which is generated by a history record generating means 4 with another history records and judges whether or not the value obtained by adding the value of a head position recorded in the history control part of one history record, the length value, and the length of the history control part itself is larger than the value of a head position recorded in the other history control part. Further, it is judged whether the value of the head position recorded in the history control part of the other history record is larger than the value of the head position recorded in the history control part of one record. A history record combining means 7 combines those history records including parts between update parts when the results of those judgements are affirmative. Consequently, history records are combined when the history quantity can be reduced by combining the records to reduce the history quantity more effectively. |
