Hgst Netherlands, B.v.

International Business Machines Corporation

Anthony Edwin Welter

David Robison Hall

Gary Allan Herbst

Rajesh Koul

Shad Henry Thorstenson

James Bowling French, Jr

Sridhar Chatradhi

Timothy John Everett

Lynn Charles Berning

Christopher Scott Dudley

Christopher Scott Taylor

Thomas James Despins

Ryan Matthew Schulz

A method, apparatus and a data storage device are provided for implementing drive list mode for read and write transfers on a recordable surface of a storage device. Drive List mode provides a queue in a linked list to chain together multiple independent transfers on a single track. The multiple drive independent transfers include at least one of sequential transfers, near-sequential transfers, and random transfers on the single track. A drive list mode transfer of multiple independent transfers on the single track is enabled in one disk revolution, and requiring a single hardware setup for the drive list mode transfer.

Implementing drive list mode for reads and writes for hard disk drives

Approaches for an emergency power off (EPO) power island, for saving critical data to non-volatile memory in the event of an EPO condition, for use in a hard-disk drive (HDD) storage device. The EPO power island includes a controller for detecting an EPO condition. A voltage regulator supplies power from spindle motor back EMF only to the EPO power island and to the non-volatile memory. Thus, the remainder of the hard drive controller (HDC) is isolated from the EPO power island so that it will not corrupt the data as the HDC's power supply is decaying. Using the power provided by the voltage regulator, the EPO power island transfers critical data from a memory internal to the island to a non-volatile memory external to the island, such as to a flash memory chip.

Emergency power off (EPO) island for saving critical data to non-volatile memory

Disk drives are described in which the conventional write-to-read gap is omitted in selected sectors which frees up space that can be used for other purposes including writing a higher number of bits in the user data area in the gapless selected sectors. Alternative embodiments can use the additional space for servo information such as a repeatable run out (RRO) field. Conventional servo sector SID formats can be used for both gapped and gapless SIDs, which means that during seeking and reading operations full SIDs can be read for every wedge. The tradeoff for being able to write data much closer to the gapless SIDs is that the servo system does not detect the SAM or read the TID in the gapless SIDs during write operations.

Disk drive with a subset of sectors with reduced write-to-read gap

A system and method are provided for hard disk drive command queue ordering with locational uncertainty of commands. For each command in the hard disk drive command queue, an expected access time is calculated utilizing a probability distribution for a currently executing command and a probability distribution for a candidate command. A command in the hard disk drive command queue having a minimum calculated expected access time is identified. Then the identified command having a minimum calculated expected access time is executed. The probability distribution for a currently executing command represents an ending location distribution for the currently executing command. The probability distribution for a candidate command represents a starting location distribution for the candidate command. For an estimated seek time of less than a time for one full revolution, a probability of a miss multiplied by a time of one extra revolution and multiplied by a candidate arrival probability is calculated and the result is added to an estimated seek time to provide the expected access time. For an estimated seek time of greater than a time for one full revolution, a probability of a make multiplied by a time of one extra revolution and multiplied by a candidate arrival probability is calculated and the result is subtracted from an estimated seek time to provide the expected access time.

System and method for scheduling of random commands to minimize impact of locational uncertainty

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Rochester, MN, United States of America

Anthony Edwin Welter