December 3, 2009 -- As the capacity of hard-disk drives continues to increase, the burden on the system to reliably access data on the media also increases. For read accesses in particular, this challenge is creating the need for ever-more-complex signal-conditioning and signal-processing algorithms to recover the data from the ever-decreasing signal quality—that is, lower SNR (signal-to-noise ratio)—of information coming off the media. To make the situation even more challenging, price, power consumption, and speed trends are all moving in difficult-to-address directions. Cost and energy draw must continue to decrease, and the rate at which the data comes off the disk must increase from one generation to the next. All of these factors make for a difficult but rewarding design challenge.

By Harley Burger. (Burger is a fellow at LSI Corp., with a focus on designing and marketing approaches for hard-disk drives.)