Abstract:
An apparatus for controlling a wheel motor is provided. A plurality of switches is provided for controlling a direction of current through motor coils of the wheel motor. A brushless motor control circuit is connected to each of the plurality of switches. Responsive to a request to adjust one of an angular velocity and an angular acceleration of the wheel motor, the plurality of switches are activated to place the motor coils in a predetermined configuration to maximize torque or reduce a total back electromotive force (BEMF) from the motor coils.
Abstract:
Data hologram recycling systems, methods and computer program products are configured to arrange data for storage in the intermediate data storage as data segments which are replicas of holographic storage segments for destaging to the holographic data storage, and to determine retrieval for recycling of the destaged holographic storage segments to which aggregated requests for deletion are directed. The retrieval determination may be based on a plurality of policies.
Abstract:
To improve reliability for multi-layer media, a data stream U is received for recording to a multi-layer rotating storage medium, the data stream U comprising a sequence of data bits. Each data bit U(J) is encoded into X representation bits. A first representation bit B(1,J) is recorded onto a first layer of the storage media, the second representation bit B(2,J) is recorded onto a second layer of the storage media, etc. When a request to read the recorded data U from the storage media is subsequently received, a plurality of the X representation bits are read back from the storage media and are decoded into the original data bit U(J). One embodiment employs a convolution encoding algorithm and PRML decoding algorithm. Another embodiment employs Reed Solomon encoding/decoding.
Abstract:
Data for storage by holographic data storage is arranged in an intermediate data storage as data segments which are replicas of holographic storage segments. Files of data are aggregated into the data segments, and a destaging control determines the destaging of the data segments to the holographic data storage in accordance with a plurality of policies, such as whether a segment is full, a time threshold has been reached, or whether a threshold number of segments are “open”. The intermediate data storage may be arranged into a number of partitions at least equal to the number of sources having input to the data destaging system, the partitions comprising integral multiples of the data segments.
Abstract:
Provided are a method, storage controller, and tape drive for adjusting read heads based on misregistration calculated from servo patterns. A plurality of first read heads read a plurality of servo patterns on a storage medium. A determination is made from the read servo patterns a skew at which the first read heads are positioned with respect to the servo patterns written to the storage medium. A determination is made of an adjustment factor to eliminate the determined skew. A plurality of second read heads that read the storage medium are adjusted by the adjustment factor.
Abstract:
An apparatus for controlling an electric motor is provided. A plurality of switches is provided for controlling a direction of current through motor coils of the electric motor. A brushless motor control circuit is connected to each of the plurality of switches. Responsive to a request to adjust one of an angular velocity and an angular acceleration of the electric motor, the plurality of switches are activated to place the motor coils in a predetermined configuration to maximize torque or reduce a total back electromotive force (BEMF) from the motor coils.
Abstract:
Holographic recording drives encode data for recording into a holographic medium. The steps comprise run length limited encoding three bytes of data into 5×5 matrix information, the data subject to a 4-byte error correction code; and providing the 5×5 matrix information to a spatial light modulator (SLM), as a portion of a two-dimensional pixel matrix of the spatial light modulator, for recording into a holographic image on the holographic medium.
Abstract:
Data for deduplication is received. The received data is deduplicated if selected conditions corresponding to the deduplication are satisfied, wherein the selected conditions include a deduplication ratio, a data deduplication threshold, and a data quiescence measure. Deduplication of the received data is discontinued if the selected conditions corresponding to the deduplication are not satisfied.
Abstract:
A method using an optical holographic data storage medium and an optical holographic data storage drive, comprising removeably disposing the optical holographic data storage medium in the optical holographic data storage drive, and determining whether to write information to the holographic data storage layer, and/or whether to read information from the holographic data storage layer, and/or whether to write information to the optical data storage layer, and/or whether to read information from the optical data storage layer. The optical holographic data storage medium comprises a holographic data storage layer and an optical data storage layer. The optical holographic data storage drive comprises a reflective spatial light modulator, a first lasing device, a first optical detector for detecting first laser light, a second lasing device, and a second optical detector for detecting second laser light.
Abstract:
A portable data storage cartridge comprising a housing, a first information storage medium removeably disposed within the housing, a holographic data storage medium disposed within the housing, wherein the housing is formed to include an aperture, and wherein the holographic data storage medium is disposed adjacent the aperture.