How Hardware Drivers Work
Simply described, drivers are a set of programming language that is used by the computer’s operating system to make any hardware usable. Different devices attached to the computer have a corresponding driver. The operating system, like Windows for instance, would call on these codes so that it can interact with the physical device connected to the computer and make it work.
The drivers work in the background and require almost no input from the users. Computer users would generally have to deal with drivers only during the installation of a new device. After all the drivers have been loaded correctly, the hardware would work for as long as it is still connected with the computer.
The operating system would attempt to load all the drivers installed in the computer during the boot up process. This makes them ready for the next operation, which is to run the hardware as an application requires it. For example, you want to play sounds on your computer. The moment you pull up the media player, the sound drivers are called upon so the sound card would process the sounds needed and blare out music as you want it.
All driver information are fed into Function Dispatch Tables, which are filled with entries that guides the operating system to select the function that it requires. The requests for a certain task called by the platform are referred to as the IRQ, or the Input / Output Request Packets. The drivers receive these requests and process it accordingly. It would either do the job as it is called for or put them in queue just in case it is busy with something else. It is also possible for the driver to return with an error code that informs the operating system that it can’t perform the task at hand.
All the codes or the programs carried by the operating system either works in a user mode or the kernel mode. In this case, the drivers operate in the kernel mode. This mode refers to the processes that directly interact with the computer’s memory. Regular programs like media players, word processors, and graphics software generally work on the user mode, wherein they deal with user inputs and then transfer the task to the respective drivers that are tied up with them. The drivers, on the other hand, would talk directly to the computer’s operating system, the computer memory, and the hardware it represents in a logical manner.