In the embedded space, there often isn't any type of OS or kernel between the application code and the hardware resources ("the metal"). If I want to send out

In the embedded space, there often isn't any type of OS or kernel between the application code and the hardware resources ("the metal"). If I want to send out a character through the board's serial debugging port, I don't do an open()/write()/close(), I poke the UART's transmit register. When they said "bare metal", I too thought they ran without OS which had been kind of cool.