Quantum Corporation

Hewlett Packard Enterprise Development LP

Jaewook Lee

Turguy Goker

Suayb Sefik Arslan

Hoa Le

Roderick B Wideman

James P Peng

Umang Mehta

Marc Feller

Jerry Hodges

Mike Alan Holmberg

John D Hampton

Suayb Arslan

Robert Brummet

Embodiments disclosed herein provide systems, methods, and computer readable media to access data on removable storage media via a network attached access device. In a particular embodiment, a method provides receiving one or more user provided, in the removable storage media access device, receiving data over a packet communication network for storage on a removable storage medium. After receiving the data, the method provides preparing the data for storage on the removable storage medium. After preparing the data, the method provides writing the data to the removable storage medium.

Network attached device for accessing removable storage media

The technology described herein enables data storage across storage volumes having fewer features than the storage volumes otherwise would. In one example, a method includes, in a data access system, identifying first data for storage on physical storage volumes. Each of the physical storage volumes corresponds to respective ones of data channels and control channels. The method further includes segmenting the first data into data segments corresponding to respective ones of the data channels and transferring the data segments as respective bit streams over the respective ones of the data channels to the respective ones of the physical storage volumes. The method also includes providing real-time write control to the physical storage volumes over respective ones of the control channels. The real-time write control directs a process for how the physical storage volumes write the data segments.

Data storage across simplified storage volumes

Embodiments disclosed herein provide systems, methods, and computer readable media for storing data to a plurality of physical storage volumes. In a particular embodiment, a method provides identifying first data for storage on the plurality of physical storage volumes. Each of the plurality of storage volumes corresponds to respective ones of a plurality of data channels. The method further provides segmenting the first data into a plurality of data segments corresponding to respective ones of the plurality of data channels and transferring the plurality of data segments as respective bit streams over the respective ones of the plurality of data channels to the respective ones of the plurality of physical storage volumes. The plurality of storage volumes stores the respective bit streams in the exact condition in which the bit streams are received.

Efficient data storage across multiple storage volumes each representing a track of a larger storage volume

Example apparatus and methods combine erasure coding with data deduplication to simultaneously reduce the overall redundancy in data while increasing the redundancy of unique data. In one embodiment, an efficient representation of a data set is produced by deduplication. The efficient representation reduces duplicate data in the data set. Redundancy is then added back into the data set using erasure coding. The redundancy that is added back in adds protection to the unique data associated with the efficient representation. How much redundancy is added back in and what type of redundancy is added back in may be controlled based on an attribute (e.g., value, reference count, symbol size, number of symbols) of the unique data. Decisions concerning how much and what type of redundancy to add back in may be adapted over time based, for example, on observations of the efficiency of the overall system.

Data deduplication with adaptive erasure code redundancy

A magnetic tape for use in a tape drive includes a plurality of tracks and a plurality of media defect characteristics. The plurality of tracks are laid out along a length of the magnetic tape, each of the plurality of tracks being configured to receive data that is organized into a plurality of fixed-size subdata sets each including a plurality of codeword interleaves. The data is laid out on the plurality of tracks in accordance with a tape layout allocation strategy as determined by a tape layout module. The tape layout module includes a tape layout optimization system that receives information on the plurality of media defect characteristics, the tape layout optimization system determining the tape layout allocation strategy based at least in part on at least one of the plurality of media defect characteristics; and the tape layout optimization system determining the tape layout allocation strategy further based on distance spectra between pairs of the plurality of codeword interleaves.

System and method for tape layout optimization

A tape layout module for determining a tape layout allocation strategy for laying out data on tape, the data being organized into a plurality of fixed-size subdata sets with each of the plurality of subdata sets including a plurality of codeword interleaves, the tape including a plurality of media defect characteristics, includes a tape layout optimization system including a processor that receives information on the plurality of media defect characteristics. The tape layout optimization system determines the tape layout allocation strategy based at least in part on at least one of the plurality of media defect characteristics. Additionally, the tape layout optimization system can determine the tape layout allocation strategy further based on distance spectra between pairs of the plurality of codeword interleaves. Further, the tape layout optimization system can determine the tape layout allocation strategy by selectively utilizing at least one tape layout parameter.

A technique includes in a data storage device, sensing a plurality of data streams from a track of storage media as the media moves in a given direction using a plurality of read elements such that at least one of the read elements is redundant. The technique includes combining the data streams to generate a data stream indicating data read from the track.

Tape storage device having at least one redundant read data element

A magnetic recording device includes a preprocessor, an interpolator and a slicer. The preprocessor receives at least n saturated input signals including an nsaturated input signal The preprocessor is configured to process each of the n saturated input signals to produce a corresponding noutput signal. The n output signals include an nm output signal from the nsaturated input signal. The interpolator processes the noutput signal to determine an ninterpolator output. The slicer determines an nslicer output for the noutput signal. The nslicer output is at one of three different levels. The preprocessor can receive and process an n +saturated input signal to produce an n +output signal that is based on a difference between the ninterpolator output and the level of the nslicer output.

Adaptive correction of symmetrical and asymmetrical saturation in magnetic recording devices

A method for inhibiting cycle slip in a tape drive having at least three channels that each utilizes a corresponding numerically controlled oscillator includes establishing a reference clock that is based on an output of the numerically controlled oscillators for at least two of the channels, comparing the output of the numerically controlled oscillator for one of the three channels with the reference clock to determine a first channel phase delta value for the one channel, and generating an error signal for the one channel if the channel phase delta value exceeds a threshold phase delta value for the one channel. The method may also include applying an inhibition loop filter to the error signal for the one channel if the first channel phase delta value exceeds the threshold phase delta value, adjusting a gain of the inhibition loop filter based at least partially upon one of the first channel phase delta value and the threshold phase delta value, and/or feeding back the error signal to the numerically controlled oscillator of the one channel.

System and method for detecting and inhibiting cycle slip for multi-channel media drive

In one embodiment, a read channel comprises: a preprocessor for receiving a first signal and producing a second signal from the first signal using current values of a positive coefficient, a zero coefficient, and a negative coefficient; an interpolator for producing a third signal based on the second signal; and a slicer for producing a fourth signal from the third signal by estimating a level for the third signal. The fourth signal is at one of three levels consisting of a positive level, a zero level, and a negative level. For every n first signals received by the preprocessor, the current value of one of the positive coefficient, the zero coefficient, and the negative coefficient is adjusted depending on which of the three levels the fourth signal is at.

In one embodiment, an interpolator-based timing recovery system improves accuracy by calculating additional sampled signals of a digital signal and generating an interpolation based on the additional sampled signals and the digital signal, while employing a parallel architecture to maintain system clock frequency and a pipeline architecture to minimize sampled data memory requirement.

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Irvine, CA, United States of America

Jaewook Lee