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The transducer-media magnetic spacing for 100 Gbit/in2 data density in hard disk drives is believed to be about 10 nm. This must include the protective overcoats on the slider and disk as well as the lubricant on the disk. Furthermore, it must make allowances for surface roughness and waviness of the disk, and possibly some pole tip recession. The result is that the mechanical spacing between the slider and disk, i.e., the 'flying height', needs to be no more than 7 nm. This talk summarizes the work at the Computer Mechanics Laboratory to develop models, software programs, optimization programs and air bearing designs to meet this goal. First we discuss briefly the use of Direct Simulation Monte Carlo methods to verify the air bearing models based on modified Reynolds equations. Then we discuss the air bearing design requirements that lead to irregularly shaped air bearing surfaces with sub-ambient pressure regions. The etching process required to produce these shapes leaves a specific wall profile that is roughly 20 microns wide and 2.5 microns deep, which must be captured in the meshing. This leads to a need for a numerical solution with irregular meshes, which is also discussed. The requirement that the flying height be constant over the data region of the disk, taking into account the skew changes for different radial positions, and be altitude insensitive, as well as being insensitive to manufacturing tolerances leads to the need for design optimization programs, which are briefly discussed. Finally, these severe conditions virtually rule out the usual contact-start-stop approach to drive design, so the air bearings must also be designed to perform well in ramp loading, or Load/Unload systems, which is also discussed. Some air bearing designs, believed to meet these requirements, are presented.