MAGNETIC DISK UNIT AND METHOD FOR EXECUTING WRITE COMMAND

• Main Authors: NAGASHIMA YASUYUKI, SASAKI KIYOTAKA, KITAHARA SHOICHI, UMEDA MICHIHIKO
• Format: Patent
• Language: English; Japanese
• Published: 04.02.2016
• Subjects: CALCULATING; CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION ANDCOMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION ANDCOMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THIR OWNENERGY USE; COMPUTING; COUNTING; ELECTRIC DIGITAL DATA PROCESSING; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; INFORMATION STORAGE; INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORDCARRIER AND TRANSDUCER; PHYSICS; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS; TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINSTCLIMATE CHANGE

PROBLEM TO BE SOLVED: To allow time of reporting of status to a host to be accelerated while guaranteeing written data.SOLUTION: A controller of a magnetic disk unit starts reception of first data specified by a first write command from a host and starts writing of the first data on a disk in accordance with the first write command. The controller reports status to the host in response to whether or not a second capacity of non-written data on the disk reduced in association with the writing of the first data on the disk is equal to a first capacity of a first space area in a nonvolatile cache capable of being utilized for saving data during a first period when power can be supplied by a backup power source in response to cutoff of a main power source of the magnetic disk unit or less.SELECTED DRAWING: Figure 1 【課題】書き込みデータを保証しつつ、ホストへのステータスの報告時期を早めることができるようにする。【解決手段】実施形態によれば、磁気ディスク装置のコントローラは、ホストからの第１のライトコマンドで指定された第１のデータの受領を開始し、前記第１のライトコマンドに従い、ディスクへの前記第１のデータの書き込みを開始する。前記コントローラは、前記ディスクへの前記第１のデータの書き込みに伴って減少する前記ディスクに未書き込みのデータの第２の容量が、前記磁気ディスク装置の主電源の遮断に応じてバックアップ電源によって電力が供給可能な第１の期間にデータをセーブするのに利用可能な不揮発性キャッシュ内の第１の空き領域の第１の容量以下であるか否かに応じて前記ホストにステータスを報告する。【選択図】 図１