Adaptive DSP generation of read thresholds for gaussian and non-gaussian distributions in solid state storage using cumulative observed counts

A storage controller system that controls solid state storage, comprising:

• a hard error correction decoder;
• a soft error correction decoder;
• and
• a processor that:
• determines a next read threshold based at least in part on a level count disparity, wherein the level count disparity is determined based at least in part on an expected count and an observed count;
• determines whether to switch from performing error correction decoding using the hard error correction decoder to the soft error correction decoder;
• and
• in the event it is determined to switch from performing error correction decoding using the hard error correction decoder to the soft error correction decoder:
• receives a plurality of read data at increments of Δ, wherein:
• a plurality of reads is performed on the solid state storage at integer increments of Δ to obtain the plurality of read data at increments of Δ;
• and
• Δ is a smallest voltage increment supported by the solid state storage;
• determines a plurality of adjacent difference counts based at least in part on the plurality of read data at increments of Δ;
• and
• determines a second next read threshold based at least in part on an inversely weighted average and the plurality of adjacent difference counts, wherein:
• a read is performed on the solid state storage using the second next read threshold to obtain second read data;
• and
• the soft error correction decoder performs error correction decoding on the second read data.