Method for recording and managing processing history information using a plurality of storage devices

A history information managing method for use in a data processing system which includes;

• at least three external storage device for storing therein history information of various lengths;
• first means for storing therein write position information indicating a position within a respective external storage device in which new history information is to be written for each said external storage device;
• and
• second means for storing therein information indicating one of said external storage devices in which history information has been most recently written;
• said history information managing method comprising:
• a first step of selecting one of said external storage devices in which the history information is to be next written in accordance with said second means;
• a second step of reading out from said first means write position information corresponding to said one of the external storage devices selected in said first step;
• a third step of writing the history information in a position indicated by said write position information which has been read out of said second step for said one of the external storage devices selected in said first step;
• a fourth step of updating the content of said second means after processing of said first step;
• and
• a fifth step of updating the write position information stored in said first means for said one of the external storage devices after processing of said second step in accordance with the length of the history information written in said third step.