As I see it.Rotary pumps are mechanically driven pumps, with individual high-pressure pipes to mechanical injectors. A mechanical priming pump may be external or part of the rotary pump. These systems have been around some time; any electronic control will be fitted to the high-pressure pump itself. (Rover 200, Vectra B)
Common rail diesel has a mechanical high-pressure pump, this is also fed by a low-pressure priming pump. The low-pressure pump can be electric (in the tank) or an additional mechanical pump mounted in the high-pressure pump. There will be one high-pressure line from the high-pressure pump to the common rail accumulator. Individual high-pressure fuel lines run from the common rail to electro-mechanical injectors. (BMW 330, Peugeot HDI etc)
Unit Injector Systems have the injectors directly driven from the camshaft in the cylinder head (no high pressure pipes). A cam acting on the unit injector directly generates the high pressure. These injectors are electro-mechanical. (VAG- PD)
Unit Pump Systems (usually commercial) have individual high-pressure pumps directly driven by a camshaft (but not in the cylinder head) with high-pressure pipes running to electro-mechanical injectors.
(Landrover?)
Common-Rail UIS/UPS usually have a fuel cooler fitted in the fuel return line due to the heating effect generated by the very high pressure. Common-Rail UIS/UPS systems have become more popular and have been around for the last 5-6 years.
HTH
G