DMA is done automatically by modern hardware, PCIe(/Thunderbolt) and SATA just do it. Somewhat related is e.g. the sendfile() syscall that's used by web server

DMA is done automatically by modern hardware, PCIe(/Thunderbolt) and SATA just do it. Somewhat related is e.g. the sendfile() syscall that's used by web servers/frameworks to pass a file directly from your fcgi application to the outgoing socket.