International Business Machines Corporation

Industrial Business Machines Corporation

Eric Rolf Christensen

Daniel James Winarski

Allen Keith Bates

Ernest Stewart Gale

Robert Allen Hutchins

Shinobu Wada

Nhan Xuan Bui

Sedat Oelcer

Said Abdullah Ahmad

Josephine F Bayang

Ara Sarkis Patapoutian

Robert G Biskeborn

David John Seagle

Reed Alan Hancock

Edwin Ralph Childers

David Berman

W Stanley Czarnecki

Diana Joyce Hellman

Shawn Owen Brume

Roger Javier Justo

Joel Hsien-Li Chen

Magnetoresistive (MR) bias is dynamically controlled in a tape drive using a processor device. Median tape head amplitude is monitored during a calibration operation, as measured across all tracks of the tape head, against predetermined thresholds of the tape drive for determining if the median tape head amplitude is below the threshold value. Upon determining the median tape head amplitude is below the threshold value during the calibration operation, a reference MR bias and a MR bias range is dynamically adjusted, during the calibration operation, for increasing the median tape head amplitude.

Dynamically controlling magnetoresitive bias

Magnetoresistive (MR) bias is dynamically controlled in a tape drive using a processor device. Upon determining head amplitude is below a threshold value, the MR bias is adjusted for increasing the head amplitude and extending the useful life span of the tape drive.

Dynamically controlling magnetoresistive bias

A method for selecting which tap coefficients of a programmable finite-impulse-response (FIR) equalizer to fix is disclosed. In one embodiment, such a method includes performing an initial calibration to determine an initial value for each tap coefficient of a FIR equalizer. These initial values may be used to produce a first waveform. The method then performs an operation on the first waveform to produce a second waveform comprising multiple lobes. The second waveform is then analyzed to determine one or more lobes of the second waveform that have the largest area. The method then fixes coefficients of one or more taps that are closest to the lobe or lobes having the largest area. A corresponding apparatus and computer program product are also disclosed.

Fixing tap coefficients in a programmable finite-impulse-response equalizer

A method for selecting which tap coefficients of a programmable finite-impulse-response (FIR) equalizer to fix includes performing an initial calibration to determine an initial value for each tap coefficient of a FIR equalizer. Using these initial values, a 'total' FIR equalizer is determined which sets the tap coefficients to their initial values. The method further determines multiple sets of tap coefficients that may potentially be fixed in the FIR equalizer. For each set of tap coefficients that may potentially be fixed, the method determines a 'fixed' FIR equalizer that sets the tap coefficients in the set to their initial values and other tap coefficients to zero. The method then determines a phase-difference energy between the &#x201c;total&#x201d; FIR equalizer and the &#x201c;fixed&#x201d; FIR equalizer for each set of tap coefficients that may potentially be fixed. The set of tap coefficients associated with the lowest phase-difference energy are then fixed.

Technique for fixing tap coefficients in a programmable finite-impulse-response equalizer

Provided are a method, system, and article of manufacture for providing removable storage management services using removable storage error information. Read/write error information is obtained for at least one removable storage by interfacing with the removable storage manager. The obtained read/write error information for the at least one removable storage is processed to determine read/write error rates for the at least one removable storage. A determination is made as to whether the determined read/write error rates for the at least one removable storage exceed at least one read/write error threshold. At least one message is sent to the removable storage manager to replace the at least one removable storage having read/write error rates that exceed the at least one read/write error threshold.

Providing removable storage management services using removable storage error information

A method of evaluating the performance of a magnetic recording system, comprising measuring a first set of finite impulse response filter tap values at time t, measuring a second set of finite impulse response filter tap values are measured at time t, where time tis subsequent to time t, and calculating an actual loss parameter using the first set of tap values and the second set of tap values. The method then compares the actual loss parameter with a total effective loss threshold.

Method to evaluate a data storage device using magnetic spacing losses

Magnetic tape devices encounter read and/or write errors when the tape is not being passed across the head with the proper tension and/or skew angle. According to one embodiment, a system which corrects for these problems comprises a head having an array of at least one of readers and writers, a drive mechanism for passing a magnetic recording tape over the head, a skew-inducing mechanism coupled to the head for adjusting a skew angle of a longitudinal axis of the array relative to a direction normal to a direction of tape travel over the head, and a controller in communication with the head. The system also determines a tape dimensional stability state of the tape and adjust the skew angle away from normal to the direction of tape travel and lowers a tension of the tape across the head if the tape dimensional stability state is in a contracted state.

Systems and methods for correcting magnetic tape dimensional instability

Provided are a method, system, and article of manufacture for accessing removable storage management services to obtain replacement instructions indicating whether to replace removable storage. Replacement information indicating whether to replace at least one of a plurality of managed removable storages is obtained by interfacing with a service computer over a network. Read/write error information for the at least one removable storage is gathered and transmitted to the service computer. Replacement instructions indicating whether to replace the at least one removable storage are received from the service computer.

Accessing removable storage management services to obtain replacement instructions indicating whether to replace removable storage

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.

Fast forward magnetic tape cartridge at first mount

A signal sampler digitally samples magnetic signals detected by read head(s) of a magnetic tape drive, and a signal quality system extracts from the digital samples of a format required signal of the magnetic signals, such as a data set separator pattern, an estimated amplitude of write equalization transitions of the format required signal; and compares the extracted estimated amplitude to acceptable amplitude.

Determination of magnetic tape write quality employing write equalization transitions

A method and apparatus is disclosed for reducing electrical noise from noise spikes in an electrical information signal. The invention can provide protection of a data storage system from soft errors rate due to noise spikes appearing in the signal from the input transducer. A cancellation signal for the low frequency component (i.e. in the system bandwidth) of the noise signal is generated. The cancellation signal is derived from a frequency band that appears in the noise spike, but does not appear in the system bandwidth for the information signal. The cancellation signal is generated in the preferred embodiment by a cancellation signal generator comprising a high pass filter and a mixer. The mixer generates a cancellation signal by processing the high frequency portion using a waveform above the normal high frequency cutoff to reconstitute the low frequency component of the noise spike in the normal frequency band. Then, the cancellation signal and the delayed input signal are combined to reduce or remove the low frequency component of the noise spike. The remaining frequency components of the noise spike can easily be removed since they are outside of system bandwidth. The invention is particularly useful in a storage system having MR heads.

Method and apparatus for removing noise spikes

Disclosed are a programmable digital device and method for generating tracking threshold signals for qualification of input peak signals in response to programmed digital gain signals which control the rate at which the envelope of the qualified input peak signals is followed, and in response to a programmed digital attenuation signal which determines the proportion of the peak envelope at which to generate new tracking threshold signals. The programmable digital device and method also provide a programmed clamp signal to clamp the positive and negative threshold signals to not fall below the programmed values. An anti-hang capability is provided to allow the thresholds to drop after a programmed time period during which no signal is detected. In an alternative arrangement, the centerline of the envelope is followed and used as the threshold.

Programmable digital centerline tracking threshold apparatus and method

Programmable digital envelope following threshold generation apparatus

A magnetic tape edge detector is provided which detects the edge of the tape by processing the noise power produced by an MR element when it is completely off the tape and the noise power produced by the MR element when it is completely on the tape. The off tape noise power is produced by factors intrinsic to the MR element and circuitry connected thereto, while the on tape noise power is produced by the heating of the MR element due to friction between moving magnetic tape and the MR element. The difference between the off tape noise power and the on tape noise power is divided by an integer greater than one to produce a reference noise signal. The reference noise signal represents a reference position of the MR element with respect to the edge of the tape. For instance, if the integer is two the MR element is at its reference position when the edge of the tape bisects the width of the MR element. The magnitude of off tape noise power is directly related to the width of the MR element. Once the reference position is detected the MR element or a plurality of interconnected MR elements can be indexed to desired information or servo tracks on the magnetic tape.

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Tucson, AZ, United States of America

Eric Rolf Christensen