| 摘要 |
PURPOSE:To attain retrieval only in a specified track range and to improve the efficiency of retrieval by forming a final track address register in an I/O control device to set up a track address at the end of key information retrieval. CONSTITUTION:A central controller executes an instruction through a communication control part 11 while making a microprogram built in a control part 20 refer the contents set up in respective control registers, from a track address register 14 to the final track address register 17. To execute the retrieving method, the address ''1'' of a track to be started to retrieve, the position ''0'' of information in a retrieval starting track, key information ''1'', and the address ''10'' of a track to be ended at its retrieval are set up in the track address register 14, the location address register 15, the data register 16, and the final track address register 17 respectively from the central controller and an instruction for retrieving key information within a specified track range is set up in an instruction register 18 as the format of an instruction code.
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