DATA READING-OUT SYSTEM

PURPOSE:To always execute read-out at a high speed by always storing a record whose use frequency is high, in a resident area, and directly reading out a necessary data from the resident area, in case of reading it out. CONSTITUTION:When a work program reads out a necessary record, for instance, records R32, R51 and R71, a key of an aggregation 23 of records being in a resident area on a main storage device 2 is retrieved by a copy 24 of a key directory. As for the record R71, its corresponding key K71 exists, and the record R71 is read out of the aggregation 23 of recordes stored in the record resident area on the device 2 and it is delivered. On the other hand, in case of the records R32, R51, their corresponding keys K32, K51 do not exist, therefore, whether they exist in an aggregation 21 of records being a buffer area on the device or not is decided as usual. In case of the record R32, it exists, therefore, the record R32 is fetched from the aggregation 21, and the corresponding use time T2 of a buffer management table 22 is udpated. The record R51 dose not exist, therefore, it is transferred to a buffer of the oldest use time on the device 2, and R51 is fetched from the aggregation 21 and delivered.