A driver is a piece of software that allows your operating system to communicate with whatever’s connected to it. Without it, the operating system doesn’t know what to do with the device. In our case, it’s important because without it your computer won’t recognize the Taranis, and you’re pretty much hosed in terms of updating your firmware. Without getting too deep into the weeds, the particular device that the computer has to talk to is the UART. That definition is down the list a bit.