"The API is a device-independent interface to the hardware of the computer.
What this means is that a program written for a Operating Systems (OS) doesn't need to know the actual mechanics of how the keyboard works on a particular machine, or how the video display works, (...)
What this means is that a program written for a Operating Systems (OS) doesn't need to know the actual mechanics of how the keyboard works on a particular machine, or how the video display works, (...)