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Partial Response/Maximum Likelihood (PRML) ist ein Leseverfahren, um Daten von magnetischen Datenträgern, wie Festplatten, mit höherer Schreibdichte zu lesen. (de) In computer data storage, partial-response maximum-likelihood (PRML) is a method for recovering the digital data from the weak analog read-back signal picked up by the head of a magnetic disk drive or tape drive. PRML was introduced to recover data more reliably or at a greater areal-density than earlier simpler schemes such as peak-detection. These advances are important because most of the digital data in the world is stored using magnetic storage on hard disk or tape drives. Ampex introduced PRML in a tape drive in 1984. IBM introduced PRML in a disk drive in 1990 and also coined the acronym PRML. Many advances have taken place since the initial introduction. Recent read/write channels operate at much higher data-rates, are fully adaptive, and, in particular, include the ability to handle nonlinear signal distortion and non-stationary, colored, data-dependent noise (PDNP or NPML). Partial response refers to the fact that part of the response to an individual bit may occur at one sample instant while other parts fall in other sample instants. Maximum-likelihood refers to the detector finding the bit-pattern most likely to have been responsible for the read-back waveform. (en) Dans le domaine du stockage informatique, PRML est le sigle de Partial Response Maximum Likelihood. C'est la méthode de conversion du signal analogique (issu de la tête de lecture magnétique) en un signal numérique. (fr) Partial Response Maximum Likelihood ( PRML ) とは、パーシャルレスポンス方式と最尤復号を組み合わせた信号処理技術である。主にハードディスクドライブ ( HDD ) で、読み出されたビットの誤り率を低減する手法として広く利用されており、磁気記録媒体の高密度化に貢献した。 より性能の高い低密度パリティ検査符号 ( LDPC ) が PRML の替わりに利用される場合もある。 (ja) |
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Partial Response/Maximum Likelihood (PRML) ist ein Leseverfahren, um Daten von magnetischen Datenträgern, wie Festplatten, mit höherer Schreibdichte zu lesen. (de) Dans le domaine du stockage informatique, PRML est le sigle de Partial Response Maximum Likelihood. C'est la méthode de conversion du signal analogique (issu de la tête de lecture magnétique) en un signal numérique. (fr) Partial Response Maximum Likelihood ( PRML ) とは、パーシャルレスポンス方式と最尤復号を組み合わせた信号処理技術である。主にハードディスクドライブ ( HDD ) で、読み出されたビットの誤り率を低減する手法として広く利用されており、磁気記録媒体の高密度化に貢献した。 より性能の高い低密度パリティ検査符号 ( LDPC ) が PRML の替わりに利用される場合もある。 (ja) In computer data storage, partial-response maximum-likelihood (PRML) is a method for recovering the digital data from the weak analog read-back signal picked up by the head of a magnetic disk drive or tape drive. PRML was introduced to recover data more reliably or at a greater areal-density than earlier simpler schemes such as peak-detection. These advances are important because most of the digital data in the world is stored using magnetic storage on hard disk or tape drives. (en) |
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