Abstract: Disclosed is a method of operating a data identification system.

Abstract: Disclosed are systems, methods, and computer readable media for restoring virtual machines. In a particular embodiment, a non-transitory computer readable medium is provided having instructions stored thereon that, when executed by a computer system, cause the computer system to perform a method for restoring virtual machines. The method comprises generating a snapshot of a storage volume representing a virtual machine in a virtual machine environment and storing the snapshot in the virtual machine environment which tracks changes to the snapshot that occur since the snapshot was generated. Based on the changes, the method provides merging differences between the storage volume and the snapshot.

Abstract: A request for a physical import/export (I/E) slot is satisfied using a tape library slot that is not a physical I/E slot. According to one embodiment, the request for the physical I/E slot, that is associated with the tape library, is received. A different slot, which is not any of the physical I/E slots associated with the tape library, is used to satisfy the request.

Abstract: Techniques for operating tape heads are provided. In an example, a method includes detecting a potential at a sensor region, determining a target potential using a transfer function, and applying the target potential to an effector region.

Abstract: Embodiments disclosed herein provide systems and methods for creating snapshots from a list of changed blocks. In a particular embodiment, a method provides establishing a base state for a data storage volume having a file system, creating a snapshot of the data storage volume, and restoring data items by merging the snapshot and the base state.

Abstract: A head rotator assembly for positioning a head of a tape drive relative to a storage tape that moves over the head comprises a head supporter and a supporter mover assembly. The head supporter is coupled to and supports the head. The supporter mover assembly includes a first actuator that indirectly rotates a portion of the head supporter about an axis to move the head in an azimuth direction relative to the storage tape as the storage tape moves over the head. The supporter mover assembly can further include a first lever. The first actuator moves the first lever to rotate the portion of the head supporter so that the head moves in the azimuth direction relative to the storage tape.

Abstract: A method for associating a physical address with a logical communication address for an Ethernet-connected media drive (22A1-22A4, 22B1-22B4) in a media library assembly (10) includes the steps of providing a first media drive (22A1) having a first physical address; sending a request for a first logical communication address from the first media drive (22A1) to a library controller (16) via an Ethernet switch (18) the first physical address being imbedded in the request; and recording the first physical address with the Ethernet switch (18). The method can include associating the first physical address with one of a plurality of Ethernet switch ports (26A1-26A4, 26B1-26B4) using a mapping server (25) of the library controller (16). The method can include searching a routing table (228) of the Ethernet switch (18) with the library controller (16) to determine the first physical address.

Abstract: 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.

Abstract: Example apparatus and methods protect state in a file system using a message-passing multi-threaded journal. One example apparatus stores, in memory, data and metadata affected by a file system transaction. The apparatus may run a thread that receives the file system transaction from the file system and that produces a set of atomic operations configured to complete the file system transaction. The apparatus may also run a thread that records a set of journal entries associated with the set of atomic operations to protect the file system while the atomic operations complete. The journal entries may be written on a non-volatile computer-readable medium. The apparatus may also run a thread that co-ordinates usage of space on the computer-readable medium. Rather than synchronizing journal activity with locks, the threads running on the example apparatus may synchronize their activity using message passing.

Abstract: Example apparatus and methods reserve space in a journal using an observation based approach instead of a fixed sized approach or a worst case scenario approach. One example method receives a request to allocate space in a journal to support a file system transaction. The example method reserves an amount of space in the journal based on a pre-existing reservation size estimate. Unlike conventional systems, the estimate is not based on a worst-case scenario. The example method observes the actual amount of storage used in the journal by the file system transaction and then selectively automatically adjusts the pre-existing reservation size estimate. The estimate may slowly shrink if no overflows are encountered but may quickly grow if an overflow is detected.

Abstract: Disclosed is a method of operating a data storage system. The method comprises generating first metadata describing storage of a volume of data in a first storage volume, storing the volume of data within a second storage volume, generating second metadata describing storage of the volume of data in the second storage volume, and processing the first metadata and the second metadata to increase sparseness of the volume of data stored in the second storage volume.

Abstract: A method for mover transition in an open systems based media library (14) for use with a host (10) that relays command requests comprises the steps of retaining a storage medium (20); selectively moving the storage medium (20) within the media library (14) with a first media mover (26); and when the first media mover (26) has a status of unavailable due to mover transition, indicating to the host (10) with a control system (40) that the first media mover (26) is not ready to perform a motion operation, and is in the process of becoming ready. Additionally, the host (10) continues to relay command requests to the media library (14) when the first media mover (26) has the status of unavailable, and the control system (40) performs any subsequent command requests relayed by the host (10) when the first media mover (26) subsequently has the status of available.

Abstract: A data control system comprises a communication interface, a processing system, and a storage system. The communication interface is configured to receive a request to retrieve data from a primary storage volume that includes a secondary storage volume. The storage system is configured to store the primary storage volume that includes the secondary storage volume. The processing system is configured to identify changed segments of a plurality of segments in the primary storage volume and identify allocated segments of the changed segments. The communication interface is further configured to transfer the allocated segments in response to the request.

Abstract: Embodiments disclosed herein provide systems and method for storing metadata to unused portions of a virtual disk file. In a particular embodiment, a method provides selecting a virtual disk file stored on a data storage volume and identifying unused portions of the virtual disk file. The method further provides writing metadata for the virtual disk file in the unused portions of the virtual disk file.

Abstract: A data storage network is provided. The network includes a client connected to the data storage network; a plurality nodes on the data storage network, wherein each data node has two or more RAID controllers, wherein a first RAID controller of a first node is configured to receive a data storage request from the client and to generate RAID parity data on a data set received from the client, and to store all of the generated RAID parity data on a single node of the plurality of nodes.

Abstract: A head rotator assembly (22) for positioning a head (20) of a tape drive (10) relative to a storage tape includes a head supporter (230) and a supporter mover assembly (232). The head supporter (230) is coupled to and supports the head (20). The supporter mover assembly (232) selectively rotates a portion of the head supporter (230) about an axis (241) to move the head (20) in an azimuth direction relative to the storage tape as the storage tape moves over the head (20). The head rotator assembly (22) further includes a controller (16) that controls movement of the supporter mover assembly (232) based at least partially on a positioning signal. The supporter mover assembly (232) can include a first actuator (234A) and a first lever (236A). The first actuator (234A) moves the first lever (236A) to rotate the head supporter (230) so that the head (20) moves in the azimuth direction. The first actuator (234A) can include a piezoelectric element.

Abstract: An apparatus and method for providing adaptive disturbance compensation with multi-rate synchronized sampling is disclosed herein. The dynamic disturbance occurring in a media drive during read/write operations is attenuated using the adaptive disturbance compensation scheme. A plurality of compensation filters are used, each of the compensation filters configured to attenuate a disturbance caused by a particular source within the media drive. Each of the compensation filters is computed based on a sampling rate relevant to the respective disturbances.

Abstract: 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.

Abstract: Methods and apparatus are provided related to magnetic recording tape. Respective voltage sources are coupled to respective magnetic head components of a tape recording apparatus. Circuitry controls each voltage source independently in accordance with identity information for a magnetic tape, relative humidity within the tape recording apparatus, or other factors. Chemical migration from the tape, and/or plating or erosion of elements of the tape recording apparatus are substantially reduced or eliminated according to the present teachings.

Abstract: A method of operating a data management system includes establishing a base state for a data storage volume, generating a list of blocks associated with the data storage volume that have changed, and creating a snapshot from the list of blocks.