partial response maximum likelihood (PRML)
The PRML method, Partial Response Maximum Likelihood (PRML), is a recording method developed by Quantum for magnetic and optical storage media. For example, for hard disks, tape drives, compact discs and DVDs.
In the PRML process, the signal is digitally sampled and the bit sequence that matches the pattern with the highest probability is searched for. The PRML method offers a much higher storage density than Run Length Limited( RLL). This increase in storage density is about 30%.
When playing back disks with high storage density, the playback signal may contain significant distortion and other noise due to interference from adjacent data. The data can be played back correctly by eliminating the signal noise with PRML.