Thermal stability analysis on pattern dependent BER and SNR decay

Thermal fluctuation plays an important role in magnetic recording system and it has to be seriously considered when designing recording media and hard disk drive (HDD) system. Unfortunately, it is impossible to perform several-year-lasting thermal stress tests to measure thermal stability during the design cycles of HDD products. Usually, the long term thermal stability was predicted by fitting the plot of bit error rate (BER) vs. logarithmic time measured from short term decay testing, and extending to certain time point such as 5 years or 10 years. However, this method is not accurate because the trend or slope of BER decay vs. log(time) would accelerate rather than stay constant, as shown in figure 1. In this work, a hybrid method will be provided to analyze pattern dependent BER and SNR thermal decay, reveal their intrinsic correlation, and help to estimate their long term trends .