International Business Machines Corporation

Other

John James Gniewek

Alex Chliwnyj

Joseph M Harvilchuck

Arnold F Schmeckenbecher

Donald W Baudrand

Rebecca P Fleming

Ernest Stewart Gale

Robert Beverley Basham

Robert Allen Hutchins

James F White

Scott Milton Fry

Steven Douglas Johnson

Michael J Sullivan

Steven Carter Wills

Timothy Martin Reith

Steven Bennett Wilson

David C Graves

A servo system and method for calibrating servo index positions of a magnetic tape for track following linear servo edges, each servo edge comprising an interface between dissimilar recorded servo signals, the edges on opposite lateral sides of a middle servo signal. A servo loop laterally positions a servo sensor where the servo signals are at estimated ratios representing the locations of the servo edges. An independent position sensor indicates the mechanical lateral position of the servo sensor at the sensed servo edges. The servo loop repositions the servo sensor to a plurality of lateral positions at predetermined displacements from the independent position sensor sensed servo edges, and track follows at each of the predetermined offsets. The ratio of the sensed servo signals is determined for each predetermined displacement, and a two dimensional, second order curve is fitted to the ratios with respect to the predetermined displacements to calibrate expected position error signals at the offset servo index positions.

Calibration of servo index positions of a magnetic tape employing second order curve fitting

A servo position detector and a method for detecting and following an index position displaced at an offset with respect to an edge of a servo track, an edge comprising an interface between two dissimilar recorded servo signals. The servo track has two edges on opposite lateral sides of a middle recorded servo signal, the edges separated by a predetermined distance. A servo read element has an active sensing region which is no more than and is substantially the entire predetermined distance separating the edges, thereby.sensing no more than two of the dissimilar recorded servo signals at one of the edges. An independent position sensor senses the coarse position of the servo read element, indicating which edge or which index position is aligned with the servo read element. Logic compares the two sensed servo signals to determine the ratio therebetween, and determines an error between the compared ratio and a predetermined ratio. The predetermined ratio is an offset from a centered on-edge ratio, and identifies the index position. The logic provides the servo position error with respect to the index position. A servo positioner moves the servo read element to reduce the servo position error.

Detection of indexed servo positions displaced from servo track edges

A servo system and method for initializing and calibrating a track following servo for following an index servo position displaced laterally from an edge, the edge comprising the interface between two dissimilar servo signals. A servo head is moveable laterally and a servo detector determines a ratio related to the two dissimilar recorded servo signals, the ratio representing the lateral position of the servo head with respect to the edge. An independent position sensor determines the mechanical lateral position of the servo head. The servo head is nominally aligned at a lateral position at which the servo detector provides a ratio representing the edge. The mechanical lateral position of the independent position sensor is measured at the nominal alignment of the servo head. Then, the servo head is repositioned laterally the predetermined displacement distance from the nominal alignment as determined by the independent position sensor. The repositioned ratio of the servo signals is measured at the displaced distance, comprising index ratio for initializing and calibrating the track following servo.

Initialization and calibration of a recording system track following servo

Optimizing the retrieval of blocks of data from a tape media of a longitudinal serpentine tape drive. A device block map (DBM) is retrieved from the tape media and stored in memory. The DBM comprises a table having one or more rows and one or more columns for each block of data stored on the tape media. The columns are selected from the group comprising a wrap column, a position column, a logical block column, and a file identifier column. One or more retrieval paths for requested blocks of data are determined from an image of the physical layout of the requested blocks on the tape media generated by linear interpolation of the DBM stored in memory. Each of the retrieval paths comprises an ordered sequence of the blocks of data and the manner in which the tape media is to be traversed to accomplish the retrieval of the ordered sequence. A sum of distances is determined for each of the retrieval paths and an optimal one of the retrieval paths is selected based on the determined sum of distances. Thereafter, the blocks of data are retrieved from tape media using the optimal retrieval path.

Host-available device block map for optimized file retrieval from serpentine tape drives

A process for simultaneously selectively depositing a high purity nickel containing alloy (i.e. a nickel-boron alloy having a nickel content in excess of 99.5 percent) over a preformed metallurgy pattern (including the individual, electrically isolated contact pads and the seal band area thereon) on the top-side dielectric surface of a multi-layer ceramic module. The metallurgy pattern on such top-side surface of such module is appropriately catalyzed and then immersed in a bath which is essentially lead-free and which includes a source of nickel ions, a borane reducing agent, and an effective amount of an organic divalent sulfur compound, preferably thiodiglycollic acid. The contact pads and the seal band area so plated exhibit an exceptionally uniform layer of nickel-boron alloy, free of surface irregularities, which layer is characterized by low contact resistance, excellent wire bonding and eutectic diode bonding characteristics and is both crack-free at the time of its being deposited and remains crack-free under brazing conditions throughout the life of the component.

Process for selectively depositing a nickel-boron coating over a

Access time is improved in a automated library system having sequentially stored data on a recording tape medium. A multiplicity of copies of the data is stored on different tape cartridges. The copies and the original are stored in different areas of the library. Each data segment stored on the tape media copy is stored in different areas of the media length from the original. The multiple copies are created and deleted independent of any user control. The usage of the original and any copies determine the number of copies and their residence times. The library manager selects the tape cartridge that can be retrieved in the shortest response time using the location of the original and the copies, the location on each cartridge of the data requested, the drive and library robot picker availability and the respective queues.

Method and apparatus for reducing response time in automated library

A system uses prevent and detect mechanisms to enable rewritable data storage media to be operated as a written-once-only media. A physical indication of the media casing serves as an indicator of the write-once-only status of the media. A watermark is magnetically recorded on the media at the factory with a portion of the mark detectable by the system and a portion only detectable by returning to an inspection station for verification. This protects against a complete erasure of all data from the media. A segment write status indication serves to indicate the write-once-only status of each segment of the written data. A portion of the written region, such as the preamble or control field of each segment, contains a status mark written randomly within the area as a status indication that the data was written once or multiple times within that segment. Three status mark areas in each segment write status region provides the minimum space overhead for achieving the desired degree of protection against overwrite or a pattern repetition.

Rewritable media protectable as written-once-only media and system and

Use of a rare gas in combination with oxygen or nitrogen to sputter etch unreacted platinum after formation of a platinum silicide contact structure for the formation of a Schottky Barrier diode in a silicon semiconductor substrate.

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Tucson, AZ, United States of America

John James Gniewek