International Business Machines Corporation

Atsushi Tobari

Hideo Asano

Hiroaki Suzuki

Akihiko Aoyagi

Tetsuo Ueda

Lee K Dorius

Kenji Ogasawara

Takashi Nakamura

Toshio Kakihara

Haruo Andoh

Koji Kurachi

Kazushige Okutsu

Shuji Yamada

Takao Chikazawa

Tsuyoshi Matsumoto

Tsuguaki Kowa

Satoshi Nishino

Yoshihiro Nakagawa

Tatsushi Aoki

Atshushi Kanamaru

A magnetic head has a left side rail formed on a disk facing surface in a protruded manner, and a right side rail formed on the disk facing surface in a protruded manner. A cross rail formed on the disk facing surface protrudes and is elongated continuously to both the left side rail and the right side rail. A left air bearing surface is formed on the disk facing surface in a protruded manner, and formed only on a side of a leading edge continuously from the left side rail. The left air bearing surface has a continuous portion to the left side rail, and a right air bearing surface which is formed on the disk facing surface in a protruded manner, formed only on a side of the leading edge continuously from the right side rail. The left air bearing surface has a continuous portion to the right side rail, wherein a recessed portion is constructed on the disk facing surface so as to be surrounded by the left side rail the left air bearing surface, the cross rail, the right air bearing surface, and the right side rail. At least part of the recessed portion produces negative pressure.

Hard disk drive magnetic head air bearing surface design for preventing particulate contamination thereon

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

An error recovery procedure (ERP) in a storage device such as a rotating magnetic hard disk drive is executed to the last step regardless of the established time-out period for an instruction, thereby more reliably recovering from errors. In accordance with one embodiment of the invention, when a disk drive receives a reset instruction from a host during the execution of an ERP, it executes the ERP until the error is recovered, or to the last step without interrupting the ERP. Further, in accordance with another embodiment of the invention, when a disk drive receives a reset instruction during the execution of an ERP, it stops execution of the ERP and holds the number K of the step which was completed immediately before stopping, and when receiving a retry instruction after that, sequentially executes the ERP from the K+1-th error recovery step.

Method for executing an error recovery procedure

The present invention provides a method and apparatus to efficiently switch heads in a disk drive. A disk drive comprises a plurality of recording surfaces and a plurality of heads and each head is opposed to a recording surface. The heads are used for reading data from or writing data to the plurality of recording surfaces. An offset quantity table stores an offset quantity for each of the plurality of heads. The offset quantity is a value representative of the distance of a head with respect to a reference head. A head sequence table stores a predetermined head switching sequence. Head switching operations use the head switching sequence stored in the head sequence table.

Disk drive apparatus and head switching method in a disk drive apparatus

In the slider 1 on which a transducer 5 is mounted and which moves above a recording surface 4, in order to generate different vibration modes according to various situations such as vertical lift-off and landing, and breaking away from stiction, etc. A plurality of piezo-electric elements 8A, 8B, 8C, and 8D are disposed on the slider 1 and means for supplying a different AC voltage to each of the piezo-electric elements 8A, 8B, 8C, and 8D is provided.

Magnetic disk slider having piezo-electric vibration elements

A magnetic head device comprising a magnetic core member made from a magnetic material having a positive magnetostriction constant and having confronting pole pieces separated by a non-magnetic material to form a transducing gap. A coil is wound around the magnetic core member so that a read signal can be read out from the coil, and a d.c. bias magnetic field is generated in the magnetic core member when a read signal is read out from the coil so that distortion of the read signal is suppressed.

Magnetostrictive head with d.c. bias magnetic field

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Fujisawa, Japan

Atsushi Tobari