The most obvious data input and output interfaces are those whose ports are located on the outside of the machine. Modern Macs have a number of built-in interfaces that you can use to move data into or take data out of the machine.
Note
All data that travels around your Mac eventually moves from one device to another. When data “crosses over,” it is said to have crossed a bus. A data bus is simply a channel through which data flows. There are many buses inside your Mac, and all devices have at least one bus (the point at which data enters or leaves the device).