What spools the turbo in a diesel truck?

In a diesel and petrol vehicle the turbo turbine is spun via exhaust gases exiting from combustion from the engine. it takes a short amount of time for a turbo to produce boost because of the effect of waiting for combustion and exhaust gases to spin the exhaust turbine. but saying this the turbocharger creates no load on the engine, not like a supercharger which is belt driven off the crankshaft which means you have to give power to make power. two sides to the turbocharger featuring intake and exhaust. while exhaust gases spin the exhaust turbine, which is connected to the intake turbine it spins the intake side creating a vaccuum and compression of the intake air. so with more revs and more exhaust gas created it also increases boost or air intake at the same time.