Read-reference BER categorization improvement in WPOH measurement of HAMR drive

Bit-error rate (BER) is used as a primary metric in write power-on hours (wPOH) measurement of heat-assisted magnetic recording (HAMR) drive. BER is measured after writing process represented writing quality while read-only BER showed reading quality or read reference in the measurement. The read-reference BER usually remains close to its initial value, however, in some cases it shows BER fluctuation or degradation as well. Therefore, in this paper focuses on the read-reference BER categorization and an improvement of the categorization algorithm.