International Business Machines Corporation

Hitachi Global Storage Technologies Netherlands B.v.

Hgst Netherlands, B.v.

Hitachi Global Storage Technologies

Hitachi Global Storage Technologies B.v.

Hitachi Global Technologies

Spencer W Ng

Richard M H New

Frank R Chu

Martin Aureliano Hassner

Jaishankar Moothedath Menon

Motoyasu Tsunoda

Daniel Jonathan Auerbach

Richard L Mattson

Richard K Treiber

Frank Rui-Feng Chu

Mario Yamaguchi

Jonathan Mark Haswell

Steven Robert Hetzler

Bruce Alexander Wilson

Nimrod Megiddo

Marco Sanvido

Windsor Wee Sun Hsu

Michael Anthony Moser

Honesty Cheng Young

Kirk Hwang

George Anthony Dunn

Hsieh T Hao

Richard Michael Hamilton New

Jorge Campello

David W Palmer

Richard S Thompson

Windsor Wee Hsu

A method for implementing data storage and a dual port, dual element storage device are provided. A storage device includes a predefined form factor including a first port and a second port, and a first storage element and a second storage element. A controller coupled between the first port and second port, and the first storage element and second storage element controls access and provides two separate data paths to the first storage element and second storage element.

Implementing data storage and dual port, dual-element storage device

A method and apparatus for deferring media writes for emulation drives are provided. By deferring media writes using non-volatile storage, the performance penalty associated with RMW operations may be minimized. Deferring writes may allow the RMW operations to be done while the disk drive is idle. Further, deferring writes may also allow data blocks to be accumulated over time, allowing a full (4K) disk drive block size to be written with a simple write operation, thus making a RMW unnecessary.

Non-volatile cache in disk drive emulation

A disk drive that includes nonvolatile memory monitors the drive's reliability-related parameters to detect real or potential failure events, and records failure-related data in nonvolatile memory, rather than in reserved areas of the disks. The monitoring may be by running a diagnostic routine or by regular or periodic monitoring of disk drive sensors, like temperature and shock sensors. The failure events to be monitored and recorded may include defective data sectors. When a new defective sector is detected after the disk drive has been put into operation, that defective sector is taken out of service and its logical block address (LBA) is mapped to a memory space in the nonvolatile memory rather to a reserved spare sector on the disk. When a read or write command is received for an LBA range that includes the defective sector's LBA, the defective sector is skipped while the whole LBA range of the command is processed and the user data for the defective sector's LBA is read from or written to the mapped memory space in the nonvolatile memory.

Disk drive with nonvolatile memory for storage of failure-related data

A magnetic disk for a hard disk drive comprising a plurality of physical sector sizes is disclosed. The magnetic disk includes a first sector size area physically formatted according to a first physical sector size and a second sector size area physically formatted according to a second physical sector size different from the first sector size by a multiple of the first sector size wherein the second sector size can be presented externally as multiple sectors of said first sector size.

Mixed format disk drive

WORM safeguards are provided in a magnetic disk drive in which the disks are pre-magnetized or pre-recorded such that all magnetic domains on each recording surface are completely aligned pointing in the same direction. A special write head which can magnetically write only in the direction opposite to the pre-magnetization orientation is also provided.

System and method for WORM magnetic recording

A mobile computing hard disk drive has both a flash memory device and a DRAM device, with the HDD controller managing data storage between disk, DRAM, and flash both when write requests arrive and when the HDD is idle to optimize flash memory device life and system performance.

HDD having both DRAM and flash memory

A hybrid disk drive, i.e., a disk drive with two types of permanent storage media (conventional disk media and nonvolatile memory, such as flash memory), uses its nonvolatile memory in operational modes other than the power-save or 'standby' mode wherein the disks are spun down. In a first additional mode, called a 'performance' mode, one or more blocks of write data are destaged from volatile memory (the disk drive's write cache) and written to the disk and simultaneously one or more data blocks of write data are destaged from the volatile memory and written to the nonvolatile memory. In a second additional mode, called a &#x201c;harsh-environment&#x201d; mode, the disk drive includes one or more environmental sensors, such as temperature and humidity sensors, and the nonvolatile memory temporarily replaces the disks as the permanent storage media. In a third additional mode, called a &#x201c;write-inhibit&#x201d; mode, the disk drive includes one or more write-inhibit detectors, such as a shock sensor for detecting disturbances and vibrations to the disk drive. In write-inhibit mode, if the write-inhibit signal is on then the write data is written from the volatile memory to the nonvolatile memory instead of to the disks.

Disk drive with nonvolatile memory having multiple modes of operation

For non-bursty data writes, data is written to flash memory of a hard disk drive for subsequent de-staging to disk, whereas for bursty writes data is written directly to disk.

System and method for selective write to flash memory in HDD

A RAID subsystem with a plurality of hard disk drives has each disk controller autonomously executing data scrubbing on its disks instead of requiring the RAID controller to execute data scrubbing. The data scrubbing may be interrupted upon an I/O request from the RAID controller, or it may continue if a guaranteed scrub rate is not being achieved. Data is stored in large bands of concentric data tracks, and a band may be preferentially selected for scrubbing based on frequency of reading the band, or recency of writing to the band.

System and method for autonomous data scrubbing in a hard disk drive

Stored data can be recovered from a disk array having at least 2n+1 physical disks that are capable of storing n physical disks worth of data when any two disks fail, or when more than two dependent disks fail. Data is stored in data stripes that are divided into n substantially equal-sized strips and are distributed across the n disks. Each data stripe has a corresponding parity strip that is generated by including the data strips in the data stripe only once when the parity strip is generated. The data strips of each data stripe, the copy of each such data strip and the corresponding parity strip are distributed across the disks in such a manner that the data strips of each data stripe, the copy of each such data strip and the corresponding parity strip are each on a respectively different disk of the disk array.

Method and means for tolerating multiple dependent or arbitrary double disk failures in a disk array

In a disk drive that uses large block sizes (e.g., 4 KB) for storing data and that responds to read and write requests from a client that uses small block sizes (e.g., 512 bytes), at least the starting and ending 4K blocks of read data are cached. Since much disk data that is the subject of a write request is first read, upon a subsequent write request the drive controller determines whether the starting and ending blocks are in cache and if so, writes new data to those blocks, calculates a full ECC for them, and then calculates ECC for intervening blocks and writes new data to the intervening blocks. If both starting and ending blocks are not in cache the drive controller executes either a high data integrity routine or a high performance routine as chosen by the user.

System and method for handling writes in HDD using 4K block sizes

A RAID-1 system achieves sparing by allocating 1/(2N&#x2212;1) of each storage device as a spare region, in a mirrored RAID-1 system having N pair of mated devices. The remaining portion of each device is partitioned into (2N&#x2212;2) data partitions. If a device fails, the contents of its mate are copied into the spare regions of the other devices. This preserves fault tolerance even if a second device subsequently fails.

System and method for sparing in RAID-1 system

A system and associated method efficiently complete write commands in an ISF disk drive/RAID system with minimal disk accesses to the underlying disk drives. The system updates data in a parity-based disk array system by receiving a write command to write new data. The present system minimizes the number of disk accesses. The present system completes the same or comparable write commands in a total of four accesses to the disk drives. This is realized by combining the read-modify-write operation of updating one or more sectors in an ISF cluster with the read-modify-write operation associated with updating one or more sectors in a parity-based array system, such as a RAID-5 system.

Integrated sector format-error correction code system and method for efficient writing in a disk array system

When writing to a hard disk drive, an effective track skew is used which differs from the track skew used when reading from the disk. During reads from the disk, the disk controller uses a traditional logical track layout and logical block address (LBA) numbering having a track skew value related to read settle time. A different effective track skew value, optimized for write settle time, is used, however, when writing to the disk. Logical blocks are written to the disk out-of-sequence in order to accommodate this different effective track skew value.

Turning read/write performance for disk drives with very high track density

Upon receiving a read command, a disk drive moves a read head to target data and reads the data into a read buffer. In an action called &ldquo;prefetching&rdquo;, the drive continues to read nearby data into the read buffer which doubles as a data cache. When another I/O command is present and must be serviced, prefetching is preempted thereby reducing the data read into the cache. Moving the head from the current I/O command to the next I/O command creates a delay comprising two components: seek time and rational latency. Based on the relative values of these components, a time period, less than the entire delay period, is calculated in which prefetching will continue. By continuing prefetching instead of preempting it, the likelihood of cache hits is increased because more data is available in the read buffer. Furthermore, by performing prefetching during part of the otherwise unused delay period, no performance penalty is introduced.

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San Jose, CA, United States of America

Spencer W Ng