Abstract: The basic equations for ultra thin gas film lubrication are presented. Based on the analysis of the equations, two features, the air bearing number is much high and the shear flow term includes the variable pressure, are pointed out. Then, a new and effective iterative algorithm is developed to calculate the modified compressible Reynolds equation under ultra thin gas film for magnetic head/disk lubrication. With the discrete equations, the pressure distributions of two kinds of magnetic heads, two guides and multi guides, are calculated respectively under 5 and 10 nanometers. The results show that the method is effective. It solves the unstable problem at a high bearing number, and avoids the numerical oscillation during calculation using the finite difference method in numerical calculations. Finally, the error analyze is carried out to indicate the method extraordinarily valid for gas lubricate with advantages of programming simple, and the computational speed rapid.

Key words: Finite difference method, Gas lubrication, Magnetic head/disk, Ultra-thin film