ia it possible to rewrite/port the linux kernel in... CUDA

is it even possible…and what can cuda really do? can full programs run in cuda on gpu…for egs. a game engine?

CUDA devices are optimized for a specific kind of parallel computing. It would not make much sense to run an operating system on the GPU, as it would run much slower overall than on a CPU.

Similarly, specific parts of a game engine can be offloaded to a GPU for a big performance win. PhysX did this with NVIDIA GPUs after NVIDIA bought the company, and I’m sure there are other game engines looking into this.