Abstract: A signal is encoded by receiving input data. A first portion of the input data is encoded to obtain a first set of encoded data. At least some part of the input data is processed to determine which one of a plurality of subsets the input data corresponds to. In the event the input data corresponds to a first subset having a greater signal margin (SM) than a second subset, the first set of encoded data and a second portion of the input data are output. In the event the input data corresponds to the second subset, the second portion of the input data is encoded to obtain a second set of encoded data and the first set of encoded data and the second set of encoded data are output.

Abstract: A signal is encoded by receiving input data. A first portion of the input data is encoded to obtain a first set of encoded data. At least some part of the input data is processed to determine which one of a plurality of subsets the input data corresponds to. In the event the input data corresponds to a first subset having a greater signal margin (SM) than a second subset, the first set of encoded data and a second portion of the input data are output. In the event the input data corresponds to the second subset, the second portion of the input data is encoded to obtain a second set of encoded data and the first set of encoded data and the second set of encoded data are output.

Abstract: Recovering a data signal is disclosed. Recovering includes receiving an input signal from a magnetic recording channel, sampling the input signal according to a sampling clock having a sampling phase wherein the sampling phase is determined at least in part by comparing the sampled input signal to a signal associated with a decision, and filtering the sampled input signal according to a target.

Abstract: Adapting a read channel processor is disclosed. Adapting includes determining a target output for input data from a variable target function, determining a filter output corresponding to the input data from a programmable filter having programmable filter coefficients, comparing the target output and the filter output, and recursively updating both the variable target function and the programmable filter coefficients to improve the comparison between the target output and the filter output.

Abstract: A system and method described for avoiding catastrophic error sequences in a media code sequence of symbols for data storage on a storage medium according to EPRML. The system and method includes modulation encoding user data which is to be stored on the storage medium using a modulation encoder. The modulation encoder outputs a channel code modulation output symbol sequence. The modulation code is defined according to a modulation criteria wherein the set of all possible modulation output symbol sequences is constrained in a manner which excludes certain excluded modulation output symbol sequences. A precoder precodes the channel code modulation output symbol sequence according to a precoding transfer function.

Abstract: A system and method are described for avoiding catastrophic error sequences in a media code sequence of symbols for data storage on a storage medium according to EPRML. The system and method includes modulation encoding user data which is to be stored on the storage medium using a modulation encoder. The modulation encoder outputs a channel code modulation output symbol sequence. The modulation code is defined according to a modulation criteria wherein the set of all possible modulation output symbol sequences is constrained in a manner which excludes certain excluded modulation output symbol sequences. A precoder precodes the channel code modulation output symbol sequence according to a precoding transfer function.