A PRML channel takes samples of the waveforms that represent data as they flow from the disk and uses this information to construct the data stream, rather than using the waveforms themselves.

Advantages

PRML channels, working with MR head and No-ID technologies, allow

• Faster data transfer rates.
• Fewer soft errors per MB stored.
• Filtering of the signal from the disk resulting in a 'clean' signal.

It all boils down to greater reliability for your data.