READ SYSTEM OF DATA BY UNITARITY OF INDEX INFORMATION

摘要

PURPOSE:To shorten the read time of data by storing data concerned and index information showing the data storage position in a main storage device as to data having a high access frequency and storing index information showing the data storage position in a secondary storage device in the main storage device as to data which cannot be stored in the main storage device. CONSTITUTION:When a user program 4 requests a data processing part 3 of the reading of data, a data retrieval means 31 obtains retrieval information of data concerned from a special index storage part 221 and decides whether data concerned exists in a special data part 21. When data concerned exists, it reads data in the special data part 21. When nothing i registered in index information in the special index storage part 221 and data concerned does not exist in the special data part 21, index information showing the data storage position in a data part 51 is obtained from a secondary index storage part 222, and data in the data part 51 is read. Thus, the read time of data is shortened.