SMB protocol is RPC derived iirc yes. COM is used both to expose in-process APIs that you invoke and also to do RPCs between services, but that's an implementa

SMB protocol is RPC derived iirc yes. COM is used both to expose in-process APIs that you invoke and also to do RPCs between services, but that's an implementation detail that only sometimes matters. Historically most stuff ran in the kernel (not any more) so there wasn't a big need for inter-process COM. These days there's more microkernel design but the underlying APIs were all 1980s era flat C APIs so indeed COM is of less relevance for remoting them.