Control method of control device conducting data input and output to storage devices, and control device used therefor

Abstract

When a request to conduct format process is received from the external device, a write history management table which records histories of conducted writing processes in block units is referred to confirm whether or not writing process has been conducted to the block. As a result of the confirmation, the format process is conducted to only a block, which a writing process has not been conducted, and a history of conducting the writing process of the formatted block is recorded. In conducting the format process, when a request is received to conduct reading process and/or writing process from the external device, the write history management table is referred, and only in a case that a writing process has been conducted to said block, the disk array device is accessed and a reading process and/or writing process is conducted to the block.