Abstract: In a tape having separate servo bands of patterns positioned laterally across the tape, the patterns of a separate servo band have at least one differentiating characteristic with respect to patterns of another of the separate servo bands. The differentiating characteristic allows identification of the separate servo bands. For example, the patterns of a separate servo band have differing azimuthal orientations of detectable transitions with respect to another servo band, such as being laterally inverted. In another, variations in the width of gaps of patterns are made with respect to another servo band. In another, variations are made in the number of the detectable transitions of patterns with respect to the patterns of another servo band.

Abstract: In a tape having separate servo bands of patterns positioned laterally across the tape, the patterns of a separate servo band have at least one differentiating characteristic with respect to patterns of another of the separate servo bands. The differentiating characteristic allows identification of the separate servo bands. For example, the patterns of a separate servo band have differing azimuthal orientations of detectable transitions with respect to another servo band, such as being laterally inverted. In another, variations in the width of gaps of patterns are made with respect to another servo band. In another, variations are made in the number of the detectable transitions of patterns with respect to the patterns of another servo band.

Abstract: In a tape having separate servo bands of patterns positioned laterally across the tape, the patterns of a separate servo band have at least one differentiating characteristic with respect to patterns of another of the separate servo bands. The differentiating characteristic allows identification of the separate servo bands. For example, the patterns of a separate servo band have differing azimuthal orientations of detectable transitions with respect to another servo band, such as being laterally inverted. In another, variations in the width of gaps of patterns are made with respect to another servo band. In another, variations are made in the number of the detectable transitions of patterns with respect to the patterns of another servo band.

Abstract: In a tape having separate servo bands of patterns positioned laterally across the tape, the patterns of a separate servo band have at least one differentiating characteristic with respect to patterns of another of the separate servo bands. The differentiating characteristic allows identification of the separate servo bands. For example, the patterns of a separate servo band have differing azimuthal orientations of detectable transitions with respect to another servo band, such as being laterally inverted. In another, variations in the width of gaps of patterns are made with respect to another servo band. In another, variations are made in the number of the detectable transitions of patterns with respect to the patterns of another servo band.

Abstract: In a tape having separate servo bands of patterns positioned laterally across the tape, the patterns of a separate servo band have at least one differentiating characteristic with respect to patterns of another of the separate servo bands. The differentiating characteristic allows identification of the separate servo bands. For example, the patterns of a separate servo band have differing azimuthal orientations of detectable transitions with respect to another servo band, such as being laterally inverted. In another, variations in the width of gaps of patterns are made with respect to another servo band. In another, variations are made in the number of the detectable transitions of patterns with respect to the patterns of another servo band.

Abstract: A cartridge handling system and method are provided to initialize a data storage cartridge having rewritable media and a cartridge memory for tamper resistant write once recording. During initialization of the cartridge for write once recording, selected data set information table fields of each data set are scrambled. The scrambling algorithm may employ a random number generator seeded with a unique cartridge identifier. The fields thus becomes unreadable if the unique identifier is changed, such as if the cartridge memory of the cartridge has been altered or replaced.

Abstract: Disclosed is a technique for updating a read-detect channel. A signal is processed in a read-detect channel that has one or more programmable registers. While signals continue to be processed by the read-detect channel, it is determined with a channel auxiliary processor whether to dynamically replace values of the one or more programmable registers. When it is determined that values of the one or more programmable registers are to be replaced, a channel auxiliary processor determines values for the one or more programmable registers and replaces existing values for the one or more programmable registers with the determined values. Also disclosed is a technique in which the determined values for the one or more programmable registers are determined using a sample of the signal.

Abstract: Synchronized data is written to magnetic tape while reducing the number of backhitches. A controller detects a pattern of synchronizing events for received data records to be written to tape; writes each transaction of data records to the magnetic; tape; accumulates the synchronized transactions in a buffer; and subsequently recursively writes the accumulated transactions of data records from the buffer to the magnetic tape in a sequence. A single backhitch may be employed to place the recursively written accumulated data records following the preceding data, maximizing performance and capacity.

Abstract: Data of a transaction to be synchronized is stored to a non-volatile store, and a Command Complete response is provided. Data of the transaction is supplied to a tape drive for writing to a magnetic tape. The storing, responding, and supplying operations are repeated for subsequent transactions. A Deferred Synchronize Command, specifying a previously supplied transaction, is provided to the tape drive, for writing data of the specified transaction. The tape drive, subsequent to writing all the data of the previously supplied transaction to magnetic tape, provides a Tape Command Complete, whereupon the data of the previously supplied transaction stored to the non-volatile store may be overwritten.

Abstract: In a magnetic tape drive having a plurality of stepped operational speeds, data storage logic estimates, from the effective data fill rate for a data buffer and the drive data write rate, the time cost to continue to operate the magnetic tape drive at the current stepped operational speed from a target to the next end of wrap; estimates, the time cost to force a backhitch of the magnetic tape data storage media and change the stepped operational speed to a higher stepped operational speed and operate the magnetic tape drive at the higher stepped operational speed to the next end of wrap; and determines the lesser time cost.

Abstract: An automated data storage library accesses data stored on storage media contained in cartridges in response to commands from an external host. The cartridges may include cartridge memory and a component in the library may include a cartridge memory interface for reading data from and/or writing data to the cartridge memory. When a cartridge is to be stored in the library, the library modifies the contents of the cartridge memory, or the contents of the storage media such that the data stored on the cartridge becomes inaccessible, thereby preventing access to the data outside of the library. To perform an authorized access, the library restores the contents of the cartridge memory or the storage media. Alternatively, the library provides a correction or correction algorithm to the drive to allow access to the data stored on the storage media without removing the access protection of the storage media.

Abstract: In a magnetic tape system, during lateral repositioning of a tape head between servo bands, the servo head is not on a servo band and is unable to provide servo position information. Hence, information about the lateral position may be lost. A control system selectively senses data read transducers of the tape head; and, upon detecting a servo signal of a servo band from a sensed data read transducer, determines the lateral position of the tape head with respect to the detected servo band based upon the position of the data read transducer that sensed the detected servo signal.

Abstract: A method to read (N) sequential files written to an information storage medium, and then skip the next (M) sequential files. The method initially identifies the (M) files to be skipped. After identifying the (M) files to be skipped, the method reads the (N) files.

Abstract: A recording system of a magnetic tape drive is operated to cause one separate set of write heads to write data discontinuously to magnetic tape as received, and to save the data, and, during the same operation, to cause another separate set of write heads to rewrite data to magnetic tape in a continuous arrangement. The writing may be in parallel and simultaneous. Thus, during the same operation, and at the same time, the separate sets of the plurality of write heads, temporarily write the received data to magnetic tape so that the sender can erase its copy, and rewrite the saved data to the magnetic tape in a permanent arrangement, without waiting to complete first writing received data, to complete subsequently rewriting the data, and repeating.

Abstract: In magnetic tape having separate longitudinal servo bands of servo information with superimposed data information, the separate servo bands have selected different superimposed data information, to identify the separate servo bands for independent addressability. The servo information comprises non-parallel laterally extending transitions to indicate lateral positioning, and the selected different superimposed data information may comprise a lack thereof in portion(s) of the servo bands. Where the superimposed data information is longitudinal position information of the tape, the selected different superimposed data information may comprise different longitudinal position information of one or more servo band(s). The selected different superimposed data information may comprise a band identifier in the superimposed data information of one or more of the servo bands.

Abstract: In a tape having separate servo bands of patterns positioned laterally across the tape, the patterns of a separate servo band have at least one differentiating characteristic with respect to patterns of another of the separate servo bands. The differentiating characteristic allows identification of the separate servo bands. For example, the patterns of a separate servo band have differing azimuthal orientations of detectable transitions with respect to another servo band, such as being laterally inverted. In another, variations in the width of gaps of patterns are made with respect to another servo band. In another, variations are made in the number of the detectable transitions of patterns with respect to the patterns of another servo band.

Abstract: A method to read information from a tape storage medium, where that tape includes a calibration region and a data region. The method uses a read channel having a first detection mode and a second detection mode. The method initializes the first detection mode and forms a calibration waveform comprising information read from the calibration region using the first detection mode. The method then defines a plurality of bit cell boundaries, initializes the second detection mode, and reads information from the data region using the second detection mode.

Abstract: A method of reducing data expansion during data compression is provided that allows the coding scheme used to compress data to be swapped between two or more coding schemes. Specifically, a coding window is provided that allows analysis of the compression potential of data within the coding window. The data within the coding window then is analyzed to determine the compression potential of the data. If the compression potential of the data exceeds a first predetermined value, the coding scheme used to compress the data within the coding window is swapped from one coding scheme to another. Preferably the first predetermined value is programmable and is related to the bit cost required to swap back and forth between coding schemes. The two preferred coding schemes are ALDC Lempel-Ziv 1 coding and a pass-through coding scheme wherein raw data is passed unencoded.

Abstract: In a pulse width modulated read signal channel for an optical disk drive, a data-transition threshold is maintained for data detection by a threshold tracking circuit that estimates the amplitude centerline data-transition threshold from the most recent maximum and minimum values of the read signal waveform. To improve the accuracy of the response of the centerline estimator, the threshold is increased or decreased based on the phase error at each read signal transition through the data-transition threshold. In addition, defects in the optical recording media are detected, and a defect present signal is used to inhibit the transition phase error input to the centerline estimator. This prevents the estimator from moving the threshold to an incorrect stable level. In addition, the defect present signal boosts the error feedback in the centerline estimator. The estimator then more quickly follows the read signal waveform.

Abstract: A write-once read-many (WORM) optical disk recorder automatically calibrates its laser to emit a laser beam of a desired power level. While writing data to the WORM disk, a laser test signal is written to a laser checking area termed Automatic Laser Power Correction (ALPC) field. If the emitted laser test signal has a power level outside an acceptable power level window, then inappropriate laser power is indicated. Then, in an error recovery procedure (ERP) the laser power is calibrated in the data sector to be written to using short spaced-apart laser test signals. After successful calibration, data are written to the sector. The test signals appear as burst errors that can be corrected by a suitable error correction code. If such calibration is not successful then a write calibrate sector, WCS, is created and used for an extensive automatic calibration. In the WCS both laser power level is calibrated. The calibration result information is written to WCS for later use.