Abstract: A method writes at least a group of holograms in a predetermined pattern in the holographic storage medium, and writes a directory hologram which relates to the holograms of the group to form an anchor location of the predetermined pattern. Further, a directory comprising the directory hologram is stored in a memory, and a read operation of at least one hologram of a group is initiated with an access for the directory hologram of the group at the anchor location; reading the accessed hologram, employing a matched filter to cross-correlate the read accessed hologram with an ideal version of the directory hologram derived from the directory stored in the memory; and determining whether the read accessed hologram is the directory hologram of the group.

Abstract: Methods and recording systems are configured for recording different data simultaneously at two different depths of a tilted magnetic medium, the tilted magnetic medium having a hard axis of magnetization, the axis being out of a plane of the medium and at an angle of ?10 to ?80 degrees with respect to a direction along which data are recorded, the medium being capable of having two depths of recording. A method embodies writing with selected magnetic fields whose amplitudes and whose angles with respect to the medium hard axis direction differ at the two depths of the medium such that the recorded direction of magnetization at the respective two depths can be set independently.

Abstract: Phase-error combination for a multi-channel data detection system with a phase locked loop for each channel, comprises receiving phase error information with respect to each channel; combination logic configured to combine the received phase error information and generate a combined phase error; and a phase-error output configured to apply the combined phase error to at least one channel phase locked loop. Additionally, error signal combination comprises receiving error information of a signal relevant to a phase locked loop with respect to each channel; combination logic configured to combine the received error signal information and generate a combined error signal, weighting the received error signal information from each channel, for example with reliability information. An error compensation output is configured to apply the combined, weighted error signal to at least one channel phase locked loop.

Abstract: Methods and recording systems are configured for recording different data simultaneously at two different depths of a tilted magnetic medium, the tilted magnetic medium having a hard axis of magnetization, the axis being out of a plane of the medium and at an angle of ?10 to ?80 degrees with respect to a direction along which data are recorded, the medium being capable of having two depths of recording. A method embodies writing with selected magnetic fields whose amplitudes and whose angles with respect to the medium hard axis direction differ at the two depths of the medium such that the recorded direction of magnetization at the respective two depths can be set independently.

Abstract: Phase-error combination methods for a multi-channel data detection system with a phase locked loop for each channel, comprises receiving phase error information with respect to each channel; combining the received phase error information and generating a combined phase error; and applying the combined phase error to at least one channel phase locked loop. Error signal combination comprises receiving error information of a signal relevant to a phase locked loop with respect to each channel; combining the received error signal information and generating a combined error signal, weighting the received error signal information from each channel, for example with reliability information. The combined, weighted error signal is applied to at least one channel phase locked loop.

Abstract: Frequency error combination for a multi-channel data detection system with a phase locked loop for each channel, comprises receiving frequency error information with respect to each channel; combination logic configured to combine the received frequency error information and generate a combined phase error, weighting the received frequency error information from each channel; and a frequency error output configured to apply the combined frequency error to at least one channel phase locked loop.

Abstract: Frequency error combination for a multi-channel data detection system with a phase locked loop for each channel, comprises receiving frequency error information of a signal relevant to a phase locked loop with respect to each channel; combining the received error signal information and generating a combined error signal, weighting the received error signal information from each channel, for example with reliability information. The combined frequency error signal is applied to at least one channel phase locked loop.

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: Handling a magnetic tape cartridge comprises the steps of reading cartridge mount information from the cartridge memory; determining from the cartridge mount information whether the present mount is the first mount of the magnetic tape cartridge; and if so, fast forward and rewind the magnetic tape of the magnetic tape cartridge, e.g., the fast forward is to end of tape (EOT) and the rewind is to beginning of tape (BOT). Alternatively, if the cartridge mount information indicates the present mount is the first mount of the magnetic tape cartridge; monitoring input/output with respect to the magnetic tape cartridge for write errors during the mount; determining whether the number of monitored write errors meets a predetermined threshold; and if so, fast forward and rewind the magnetic tape of the magnetic tape cartridge.

Abstract: Consistency for replicating data storage subsystem configurations in accordance with a “golden” configuration file. A data storage subsystem comprises a blade system with a plurality of slots, the blade system configured to support a plurality of blades and a storage system, each arranged in a predetermined slot of the blade system. The storage system arranges a logical configuration of the server blades in accordance with a “golden” configuration file. The server blade slot versus WWN information is collected and provided to the storage system. The storage system converts the “golden” configuration file slot information to WWNs. The server blades are enabled for access to said storage system as they log on with WWNs in accordance with the “golden” configuration file.

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 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: In a data storage subsystem with disk storage and a pair of clusters, one set of DASD fast write data is in cache of one cluster and in non-volatile data storage of the other. In response to a failover of one of the pair of clusters to a local cluster, the local cluster converts the DASD fast write data in local cache to converted fast write data to prioritize the converted data for destaging to disk storage. In response to failure to destage, the local cluster allocates local non-volatile storage tracks and emulates a host adapter to store the converted fast write data by the local non-volatile storage, reconverting the converted fast write data of the non-volatile storage to local DASD fast write data stored in the local non-volatile storage and stored in the local cache storage.

Abstract: A data storage system which copies data from source data storage volumes to target data storage volumes restricts a write operation to at least one source data storage volume (FREEZE), to prevent the updating of a source while the data of a consistency group of interdependent data is being copied. Program logic selects a source data storage volume to which the restriction applies as a verification volume; and the program logic responds to a verification request to first employ the verification volume to verify that the restriction remains in place with respect to the verification volume, and to allow a reset of the restriction (THAW).

Abstract: A data storage cartridge comprises data storage media configured to store data for read and/or write access, wherein the data may be arranged in a plurality of partitions; and a plurality of cartridge memories. A control system, for example of a data storage drive, is configured to allocate at least portions of capacity of the data storage media to cartridge memories of the data storage cartridge; and to provide information defining the allocated portions of capacity to the cartridge memories. Each of the cartridge memories may have a separate user and thus provide access for that user to separate partitions.

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: A magnetic tape cartridge, a recording system, and a magnetic tape drive are configured to, for example, guard against tampering with a write once overwrite protection pointer which allows a rewritable magnetic tape to be treated as write once. In one embodiment, the magnetic tape cartridge comprises a magnetic tape and a cartridge memory. The magnetic tape is configured to provide at least one overwrite protection pointer, the overwrite protection pointer identifying data to be protected from being overwritten; and the cartridge memory is configured to provide the at least one overwrite protection pointer, the overwrite protection pointer identifying magnetic tape data to be protected from being overwritten.

Abstract: With detection of a selected error event involving a data storage drive and data storage media, a subsystem attempts to move the media to another drive, and conduct a similar operation. The subsystem separately tracks successive error events of individual drives and individual media, wherein a complete successful operation breaks the chain of the successive error events; and upon the number of successive error events reaching a threshold, fails the data storage drive or the data storage media. Error events are categorized into: 1) error events before or during a mount of a media into a drive; and 2) error events after a successful mount of a media into a drive; and conducts the tracking, comparing and failing steps separately for each of the categories for the drives and the media.

Abstract: A data storage system writes data supplied from a host to data storage in accordance with write I/O of an owning application. A workload manager directs the processing of the supplied data in accordance with the write I/O of the owning application, provides service workload identification describing the write I/O, a storage subsystem control adds the service workload identification to record set information for the data, and a journal management system stores the record set information in a journal. The journaled information, for example, may be employed for performing forensic analysis of data corruption events or to perform security audits, etc.

Abstract: A data storage system writes data supplied from a host to data storage in accordance with write I/O of an owning application. A workload manager directs the processing of the supplied data in accordance with the write I/O of the owning application, provides service workload identification describing the write I/O, a storage subsystem control adds the service workload identification to record set information for the data, and a journal management system stores the record set information in a journal. The journaled information, for example, may be employed for performing forensic analysis of data corruption events or to perform security audits, etc.