Both Sony A100 and Nikon S01 have 10.0 MP resolution sensors but Sony A100's sensor is APS-C (23.6 x 15.8 mm ) and Nikon S01's sensor is 1/2.9-inch (4.96 x 3.72 mm ).
Since Sony A100's has a larger sensor area with the same resolution, this means that it also has a larger pixel area hence better light collecting capacity for a given aperture compared to Nikon S01.
Below you can see the A100 and S01 sensor size comparison.
As seen above, Sony A100 has a 20.2x Larger sensor area than Nikon S01. Larger sensors give photographer more control on the depth of field and blurry background compared to smaller sensor when shot in same focal length and aperture.