The hard disk drive (HDD) industry also finds its lifeblood in a technology roadmap. The areal density roadmap describes the number of magnetic bits per unit area on the disk platter--thereby defining the storage capacity. Each year the areal density increases by an average of 40 percent, enabling disk drives to play the lead role in serving humankind's insatiable thirst for reliable, compact, and economical data storage. During the first half of this decade most areal density advances have been the result of changes to the thin film head (TFH) that allow it to read and write smaller bits of data as it flies at an altitude of less than 10 nanometers above a magnetic disk platter rotating at a typical 7,500 rpm. In more recent years, areal density improvements have been attributed to changing the magnetic bits on the disk platter from a longitudinal to a more compact perpendicular orientation.

Perpendicular magnetic recording (PMR) technology and TFH advances have enabled today's state of the art areal density of over 400 gigabits per square inch (400 Gb/in²). The industry's leading 'magneticians' believe PMR can be extended to close to 1,000 Gb/in² or 1 terabit per square inch (1 Tb/in²). This will be an impressive feat, but by the end of 2011 the industry's areal density roadmap will require 1.2 Tb/in². While the HDD industry is accustomed to having only a two- or three-year solution horizon, crossing the 1Tb/in² technology barrier will not be business as usual.

The prevailing plan to avoid a cardiac arrest of the areal density roadmap involves patterning of the hard disk platters. A patterned media surface physically defines the geometric shape and placement of each bit on the disk. This feature isolation improves the signal-to-noise during the normal read/write operations of the hard drive and enables further bit shrinks otherwise unpractical due to data loss from exceeding the infamous superparamagnetic limit. (This occurs when bits become too small and their states randomly flip from thermal instability even at normal ambient temperatures.)