International Business Machines Corporation

Hitachi Global Storage Technologies Netherlands B.v.

Toshio Kakihara

Hideo Asano

Tetsuo Ueda

Atsushi Kanamaru

Yukio Fukushima

Yoshiju Watanabe

Kazushige Okutsu

Terumi Takashi

Koichi Arai

Yuzo Nakagawa

Masahiko Sato

Katsuhiro Imoto

Atsushi Tobari

Hiroshi Oshikawa

Hiromi Nishimiya

Takahiro Saitoh

Tomoyuki Oyama

Akinori Yuba

Yuhji Kigami

Takumi Satoh

Akihiko Mouri

Atshushi Kanamaru

Masahiko Satoh

Shuhji Yamada

A method for writing data to a disk drive. The method includes: receiving a write command; and, determining whether a beginning and an end of a rewrite area specified by the write command agree with boundaries of large-sized data sectors on a disk. The method also includes: reading head and tail data sectors and making a backup of the head and tail data sectors in first and second non-volatile memory areas, respectively, if the beginning of the rewrite area does not agree with the boundaries. The method includes starting a rewrite of the rewrite area after completing backups into first and second non-volatile memory areas. Moreover, the method includes: determining a state stage by using data in first, second, third and fourth non-volatile memory areas if a power shut-down occurs during execution of the write command; and, executing a recovery process in accordance with the determined state stage.

Disk drive including a host interface supporting different sizes of data sectors and method for writing data thereto

Embodiments of the present invention help to securely manage a data cryptographic key in a data storage device. In an embodiment of the present invention, a cryptographic processor for encrypting and decrypting data is located between a host interface and a memory manager. In parts of the hard disk drive (HDD), except for the host interface, the HDD handles user data in an encrypted state. A data cryptographic key which the cryptographic processor uses to encrypt and decrypt the user data is encrypted and stored in a magnetic disk. A multiprocessing unit (MPU) decrypts the data cryptographic key using a password and a random number to supply it to the cryptographic processor. Using the password and the random number, the HDD can manage the data cryptographic key with more security.

Data storage device and management method of cryptographic key thereof

In one embodiment, a HDD creates a segment table to associate an address of user data in a flash memory with an LBA in a magnetic disk. The HDD updates the segment table in a DRAM and saves it to the flash memory at a specific timing. The HDD creates journals indicating the update of the segment table and saves it to the flash memory. The latest segment table can be restored using the segment table and the journals in the flash memory.

Data storage device and data management method in data storage device

An executable command selection system and method are provided. A command is selected as the next-to-be-executed command when the execution waiting time for the command is less than or equal to a predetermined reference time. In addition, the command selected as the next-to-be-executed command has an execution waiting time greater than or equal to a scanning time. Once a command is selected as the next-to-be-executed command, calculation of execution waiting times for subsequent commands in the command queue stops. In this manner, when the number of commands in the command queue exceeds a predetermined number, the method of the present invention improves the efficiency of command execution for a storage device.

Data storage unit, executable command selection method, and data processing method

To provide a method of starting a data storage unit which allows a computer system to be used as early as possible. The present invention relates to a method for starting up a computer system having a data storage unit equipped with an actuator arm which supports a flexible cable. The method allows a command from the host computer to be processed before generation of corrected tension data for the flexible cable. The method includes the steps of turning on power; executing a start operation, excluding generation of corrected tension data of the flexible cable; causing an access command from a host computer to be in an executable state, following the step of executing a start operation; and executing generation of corrected tension data of the flexible cable, following the step of causing an access command from a host computer to be in an executable state.

Data storage unit and method for starting data storage unit

A disk device, track positioning method, and method for generating a position error signal in which the occurrence of a wrong correction operation can be prevented by creating an appropriate PES without using a burst pattern having a defect, and reassign sectors can be decreased by decreasing defective sectors thereby to reduce the performance degradation is disclosed. In the disk device and track positioning method, the defect of a burst pattern read out from a disk is detected, and if a defect is detected in the burst pattern, a data value corresponding to the sum data of the burst pattern pair having the defect detected is obtained by measuring the maximum amplitude value of the burst pattern pairing with the burst pattern having the defect detected, and a PES is created according to the amplitude of the burst pattern having the defect detected and the maximum amplitude value.

Disk device, track positioning method and method for generating a position error signal

The present invention provides a disk drive device containing a cache memory having K queue entries (K is an integer) to operate in a write cache mode and a method for controlling the disk drive device. The number of the queue entries to be used in the write cache mode can be gradually decreased from the number K to a decreased number by a predetermined number, and the number of the queue entries to be used in the write cache mode can be gradually increased from the decreased number towards the number K by a predetermined number, in response to values of parameters, such as an error rate and Non Repeatable Run Out or Repeatable Run Out of the rotating data recording disk at writing of data from the cache memory to a rotating data recording disk.

Disk drive device and a method for controlling the same

A disk drive and a control method thereof to reduce the number of write operations to a medium while minimizing command overhead time. A disk drive,comprises a hard disk controller (HDC),, a cache memory,, and a host interface controller (HIC),with a command queue for retaining a plurality of commands which are cached in cache memory,. The HIC,performs the periphery interface processing by hardware. The disk drive,further comprises a local microprocessor unit (MPU),for controlling the overall operation of HDD,, including operations of HDC,and HIC,. The local MPU,instructs the HIC,to write data to a medium by write commands cached in the cache memory,. When local MPU,retrieves a command from a plurality of write commands cached in cache memory,which is completely overwritten by a command more recently issued, a write operation to the medium is not performed by the retrieved command.

Disk drive having control mechanism to reduce or eliminate redundant write operations and the method thereof

Methods and apparatus are described for a data transfer unit between a storage unit and a host, wherein a slower data transfer rate is established when a predetermined error is detected. In one embodiment the cyclicity of the error occurrence calculated and a wait is inserted between data to avoid transferring data at the calculated cyclicity point of the detected error. Optionally the data transfer unit may return the data transfer rate to the original data transfer rate or state after a predetermined time has elapsed, after a predetermined number of commands have been received, after a predetermined amount of data have been transferred, or by combination of these.

DMA transfer from a storage unit to a host using at least two transfer rates and cyclic error detection

A disk drive unit and an error recovery method for the disk drive unit which can reduce processing time for ERP in resetting, thereby shortening response time to the reset is described. A normal error recovery procedure is executed if there is no reset request when a write error occurs, but if there is a reset request pending, a data record in which a write error occurs is registered as a defective position (e.g. sector) and an alternate (spare) position is assigned to accelerate the time when the drive can respond to the reset instruction. Data records with alternate positions assigned as a part of the reset activity are specially marked so that alternate position assignment can be undone as soon as is appropriate, for example, when the record is next read or written.

Disk drive unit and error recovery method executing shorter error

A disk drive and a method for controlling the disk drive in which an additional read from a medium can be performed as needed while minimizing the command overhead to the minimum. In a disk drive device 10, even if a read command is issued, and all the required data is stored in the cache memory such that the data transfer can be performed without the intervention of a local MPU 16, a HIC 15 performs the data transfer so as to leave the last one block and waits for the intervention of the local MPU 16. The local MPU 16 provides instructions to transfer the last one block when the preparation for the command termination is completed, and if a plurality of blocks of data to be transferred are remaining when the local MPU 16 instructs the HIC 15 to transfer the last one block, the HIC 15 executes all the data transfer without stopping the data transfer before the last one block, completing the command.

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Fujisawa, Japan

Toshio Kakihara