International Business Machines Corporation

Western Digital Technologies, Inc.

Xiotech Corporation

Michael John Shea

Gerald Wayne Swift

Mark J Bailey

Earl Albert Cunningham

Richard Greenberg

Russell A Billings

Timothy D Bouwkamp

A method, apparatus and program storage device for verifying existence of a redundant Fiber Channel path is disclosed. The present invention verifies that a redundant path exists prior to moving the WWNN and WWPN. Thus, if the path being used for Fiber Channel communication is lost, connectivity can be restored when the source of the original connection can access the physical interface where the WWNN and WWPN have been moved.

Method, apparatus and program storage device for verifying existence of a redundant fibre channel path

A surface laminar circuit board includes an insulating layer, and a signal ground conductive layer disposed on an upper surface of the insulating layer. The conductive layer has a hole formed therein. A photosensitive dielectric layer is disposed on an upper surface of the signal ground conductive layer. The dielectric layer has a photo micro-via formed therein. A signal trace is disposed on the photosensitive dielectric layer, and is electrically coupled with the signal ground conductive layer by way of the photo micro-via. A conductive pad is provided, which has a majority thereof within an area defined by an outer periphery of the hole. The conductive pad is electrically coupled with the signal trace. A surface mounted component is mounted on the conductive pad.

Surface laminar circuit board having pad disposed within a through hole

Method of making surface laminar circuit board

A disk drive employs a method of monitoring a transducer flying height to retire a defective data site on a disk. The transducer is designed to comply with a fly-height specification while flying above the disk. In one aspect, the method includes generating a warning signal representing a condition in which the transducer is flying outside the fly-height specification as a result of flying above a defect site within a physical sector having a physical sector address. The method includes associating the warning signal with a defect site address that points to the defect site and storing the defect site address in a defect discovery table. The method further includes using the defect discovery table to locate the physical sector address. The method includes storing the physical sector address in a defect management table to retire the physical sector. In another aspect, the method includes reading data stored in a data region on the disk to produce a read signal having a first fly-height varying component and a second fly-height varying component. The method further includes generating a warning signal responsive to the first and second fly-height varying components and a threshold value when the transducer means is flying outside the fly-height specification. The method includes retiring the defective data site on the disk in response to the warning signal.

Disk drive employing method of monitoring transducer flying height to retire defective data site on recording surface

A disk drive having a rotary actuator, an embedded servo system for controlling the rotary actuator, a rotating disk surface for recording and reproducing data, and a dual element head supported by the actuator comprising a read element and a write element. The disk surface has a plurality of repeating servo track patterns defining radially spaced-apart servo tracks. The disk surface further includes a user data band having a plurality of radially spaced-apart data tracks for storing user data. Each data track is written with an offset from a corresponding servo track centerline depending on a skew introduced by the dual element head. A reserved band is located outside the user data portion including a reserved data track for storing drive specific data wherein the reserved data track is centrally aligned with a corresponding servo track centerline. The reserved data track can be read reliably by the read element when the servo system is tracking on the servo track centerline. A method for making the disk drive includes writing the reserved data track in central alignment with a corresponding servo track centerline.

Disk drive with zero read offset in reserved area and method of making same

Apparatus and methods for storing predefined information with error correcting code (ECC) in a direct access storage device are provided. Predetermined information is identified and loaded to an ECC generator for customer data to be read and written. The identified predetermined information includes an address for customer data to be read and written. The customer data is written and loaded in parallel to the ECC generator. Then the generated ECC that reflects the pre-loaded predetermined information is written at the end of the written customer data. The customer data and ECC is read and loaded in parallel to the ECC generator. Errors in the predetermined information that is not written to the disk surface, can be detected from the read ECC.

Method and error correcting code (ECC) apparatus for storing predefined

A disk drive provides a defect list for each recording surface itemizing selected areas of recording surface by location, size and graded by an expected abnormal error rate. The defect list is utilized upon formatting of a recording surface to rate sectors as available or unavailable depending upon a map of data types to be written to the sectors and alignment of the map to the defects.

Growing community of inventors

Rochester, MN, United States of America

Michael John Shea