Both Tech A which stated that fixed calipers use one or more pistons and Tech B says that sliding/fixed calipers use one or more pistons on both sides of the rotor were wrong.
A fixed caliper's operation is been run on very simple operation, in the sense that a fixed caliper does not move when the brakes are applied.
In the both sides of a fixed caliper , there are pistons , then When the brakes are applied, there is application of brake pads on both sides against the rotor by the piston.
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