Brakes

Note that the cross-drilled holes overlap (around the circumference of the disc) and no part of the pad runs only on the solid disc, allowing for even pad wear.  Cross-drilling allows for rapid disc cooling and also for the removal of gas build-up from the friction material (very much like the tread on a tyre displacing water whilst running on a wet road).  Slotted discs provide a similar ability to disperse gas, however their cooling ability is similar to a solid-faced disc.

Note the scallops of metal removed from the disc, between the mounting bolts, to lower the overall weight.  Cross-drilling also assists to remove weight.

A. Steel-braided brake line, B. Cross-drilled disc (with scratch), C. Wired disc mounting bolts, D. Wilwood 2-spot caliper, E. Suspension limit strap, F. Shock piston.

The disc and caliper are both fairly old designs.  Newer discs use better forging technologies to lower the overall weight of the disc, whilst simultaneously increasing their strength and cooling capacity (e.g. the 'stalactite/stalagmite' designs used in some rotors).  Similarly, the latest calipers have varying piston diameters to offset wear due to varying temperatures across the pads (ie. the trailing edge of any pad is hotter than the leading edge, therefore a smaller piston is utilised on the trailing edge to reduce pressure/wear at this location, relative to the leading edge).

A. Steel-braided brake line, B. Ventilated disc, D. CNC 4-spot caliper, E. Suspension limit strap, F. Shock piston.

So,braking force is dictated by the bias bar position, the respective master cylinder bore sizes, the caliper piston sizes (and the number of pistons), the brake disc diameters, the brake pad material and temperature it's running at, the tyre footprint sizes, the road/track surface, and obviously how hard you push the pedal.