I know who he is and gave him the benefit of the doubt. That's why I said "I'm not sure he's understanding what this is." instead of just assuming the person h

I know who he is and gave him the benefit of the doubt. That's why I said "I'm not sure he's understanding what this is." instead of just assuming the person had no idea what they were talking about. >The read(2)/write(2) solution from userspace would involve no copying as well I don't believe this is the case as at all. First you have the context switch problem and second of all the reason sendfile can be fast is because it's possible that the kernel never touches the data. It just assigns the disk DMA to a kernel buffer, and then gives the kernel buffer location to the NIC driver to read from. All data reading and writing can be done completely with the hardware with no CPU involvement. read/write can't do it this way because you have the option of doing something with the data you get back from read. Well, it could optimistically hope that nothing will in fact be done with the data but that assumption will be wrong in nearly every single usage.