# US 7,613,975 B2 · Predictive diagnosis of a data read system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,613,975 B2 - Document ID: US7613975B2 - Status: Granted - Kind: B2 - Application number: 11/217,000 - Filed: 2005-08-31 - Published: 2006-08-17 - Granted: 2009-11-03 - Earliest claimed: 2005-02-03 - Assignees: Hewlett-Packard Development Company, L.P. - Inventors: Rafel Jibry; Peter Arthur Walsh - Web page: https://patentgrep.com/patent/US7613975B2 ## CPC - G11B 20/1816: {Testing} - G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R) ## Abstract A data read system comprising a read channel for processing a signal, and a diagnostic controller in communication with the read channel. The diagnostic controller is configured to measure at least one metric of the read channel during processing of a signal containing unknown data. The measured metric is then compared against a stored nominal metric and a warning is generated in response to a result of the comparison. In particular, the warning is generated only if the difference between the measured metric and the stored nominal metric exceeds a threshold. ## Claims ### Claim 1 A method of diagnosing a data read system comprising a read channel for processing a signal, the method comprising the steps of: measuring at least one metric of the read channel during processing of a signal containing unknown data; comparing the at least one metric against at least one stored nominal metric; diagnosing whether there is a potential problem with the data read system based on the comparison; diagnosing whether there is a potential problem with a data medium based on the comparison; and generating a warning in response to a result of the comparison. ### Claim 2 (depends on 1) A method according to claim 1, wherein the at least one metric of the read channel is measured during processing of a signal containing a data pattern for which the data read system has no a priori knowledge. ### Claim 3 (depends on 1) A method according to claim 1, wherein the at least one stored nominal value corresponds to a metric measurement made when the signal has nominal characteristics. ### Claim 4 (depends on 1) A method according to claim 1, wherein the warning is generated when the difference between the measured at least one metric and the at least one stored nominal metric exceeds a threshold. ### Claim 5 (depends on 1) A method according to claim 1, wherein the step of measuring the at least one metric comprises measuring a plurality of metrics of the read channel, the step of comparing the at least one metric comprises comparing each metric against a respective stored nominal metric, and the step of generating a warning comprises generating a warning should the difference between at least one metric and the respective stored nominal metric exceed a threshold. ### Claim 6 (depends on 1) A method according to claim 1, wherein the read channel comprises a plurality of components including a decoder and the at least one metric is measured at a point upstream from the decoder. ### Claim 7 (depends on 1) A method according to claim 1, wherein the read channel comprises a plurality of components including a maximum likelihood detector implementing a soft-output Viterbi algorithm, and the at least one metric includes the output of the soft-output Viterbi algorithm. ### Claim 8 (depends on 1) A method according to claim 1, wherein the data read system further comprises a data-read head in communication with the read channel for reading encoded data stored on the data medium and outputting in response a signal. ### Claim 9 (depends on 8) A method according to claim 8, wherein at least one metric varies according to the quality of the data medium upon which the encoded data are stored. ### Claim 10 (depends on 8) A method according to claim 8, wherein at least one metric varies according to properties of the data-read head. ### Claim 11 (depends on 8) A method according to claims 8, wherein at least one metric varies according to the separation of the data-read head from the data medium. ### Claim 12 (depends on 1) A method according to claim 1, wherein the data read system comprises a plurality of read channels, and the step of measuring at least one metric includes measuring at least one metric of each read channel, the step comparing the at least one metric includes comparing the at least one metric of each read channel against at least one stored nominal metric, and the step of generating a warning includes generating a warning when the difference between the at least one metric of at least one read channel and the at least one stored nominal metric exceeds a threshold. ### Claim 13 (depends on 12) A method according to claim 12, wherein the warning is generated only when the difference between the measured at least one metric of the majority of read channels and the stored at least one nominal metric exceeds the threshold. ### Claim 14 (depends on 1) A method according to claim 1, wherein the warning includes an indication of a problem or potential problem within the data read system. ### Claim 15 (depends on 14) A method according to claim 14, wherein the warning includes an indication of the severity of the problem or potential problem. ### Claim 16 (depends on 14) A method according to claim 14, wherein the warning includes possible remedial action. ### Claim 17 A data read system comprising a read channel for processing a signal, and a diagnostic controller in communication with the read channel, wherein the diagnostic controller is configured to: measure at least one metric of the read channel during processing of a signal containing unknown data; compare the measured at least one metric against at least one stored nominal metric; diagnose whether there is a potential problem with the data read system based on the comparison; diagnose whether there is a potential problem with a data medium based on the comparison; and generate a warning in response to a result of the comparison. ### Claim 18 (depends on 17) A system according to claim 17, wherein the system comprises a plurality of read channels, and the diagnostic controller is in communication with each read channel and is configured to: measure at least one metric of each read channel during processing of the signal; compare the metric of each read channel against at least one stored nominal metric; diagnose whether there is a potential problem with the data read system based on the comparison of each read channel of a plurality of read channels; diagnose whether there is a potential problem with a data medium based on the comparison of each read channel of a plurality of read channels; and generate a warning when the difference between the metric of at least one read channel and the stored nominal metric exceeds a threshold. ### Claim 19 (depends on 17) A data drive comprising a system according to claim 17. ### Claim 20 (depends on 19) A data-drive according to claim 19, wherein the data drive is a Linear Tape-Open (LTO) tape drive. ### Claim 21 Means for diagnosing a data read system comprising a read channel for processing a signal, the means comprising: means for measuring at least one metric of the read channel during processing of a signal containing unknown data; means for comparing the at least one metric against at least one stored nominal metric; means for diagnosing whether there is a potential problem with the data read system based on the comparison; means for diagnosing whether there is a potential problem with a data medium based on the comparison; and means for generating a warning in response to a result of the comparison.