The main difference between the device driver and device controller is that a device driver is a software program whereas device controller is a hardware unit. Device driver is a program via which the operating system communicates with the device controller. Both the terms are often used interchangeably but they are very different. Let’s look at the two.


What is Device Driver?

Device driver is a specialized software program running as part of the operating system that interacts with a device attached to a computer. It is just a code inside the OS that allows to be empowered with the specific commands needed to operate the associated device. OS manages and controls the devices attached to the computer by providing required functionality to the software programs for controlling different aspects of the devices. OS does so by combining both hardware and software techniques. The OS interacts with the I/O hardware via the device driver software. The device driver software comes along with each device. Device drivers are basically low-level programs that allow the kernel of computer to communicate with different hardware devices, without worrying about the details of how the hardware works. So, they provide the kernel with the appropriate knowledge on how to control the devices.


What is Device Controller?

Device controller is a hardware unit attached to the I/O bus of the computer and works like an interface between a device and a device driver. It is an electronic component consisting of chips that is responsible for handling the incoming and outgoing signals of the CPU. It acts as a bridge between the device and the operating system which receives commands from the OS, such as read, write or more complex commands. Each device controller has its own set of commands, depending on the nature or the manufacturer. So, there is different software running as part of the OS that interacts with each controller. Thus, there is always a device controller and a device driver associated with each device that communicates with the OS. The controller receives the data from a connected device, stores it temporarily, and then communicates the data to its device driver. So, the device controller interacts with the OS via the device driver.



Summary of Device Driver vs. Device Controller

In a nutshell, a device driver is a software program that manages and controls a specific device that is attached to a computer, while a device controller is a hardware unit that makes sense of the incoming and outgoing signals of the CPU. A device driver allows a computer to interface and interact with a specific hardware device, such as a printer, sound card, graphics card, etc. The device controller receives the data from a connected device, stores it temporarily, and then communicates the data to its device driver. Device controller acts as a bridge between the device and the operating system.