![]() Although this information can instead be learned by reverse engineering, this is much more difficult with hardware than it is with software. ![]() In such cases, it is important that the hardware manufacturer provides information on how the device communicates. But in recent years non-vendors have written numerous device drivers, mainly for use with free and open source operating systems. ![]() Typically, the logical device driver (LDD) is written by the operating system vendor, while the physical device driver (PDD) is implemented by the device vendor. Moreover, it was traditionally considered in the hardware manufacturer’s interest to guarantee that their clients can use their hardware in an optimum way. This is because they have better information than most outsiders about the design of their hardware. The task of writing drivers thus usually falls to software engineers or computer engineers who work for hardware-development companies. These factors make it more difficult and dangerous to diagnose problems. Even drivers executing in user mode can crash a system if the device is erroneously programmed. In contrast, most user-level software on modern operating systems can be stopped without greatly affecting the rest of the system. Because drivers require low-level access to hardware functions in order to operate, drivers typically operate in a highly privileged environment and can cause system operational issues if something goes wrong. Writing a device driver requires an in-depth understanding of how the hardware and the software works for a given platform function. The commands needed to control a 16550 UART are much different from the commands needed to control an FTDI serial port converter, but each hardware-specific device driver abstracts these details into the same (or similar) software interface. ![]() Purposeĭevice drivers simplify programming by acting as translator between a hardware device and the applications or operating systems that use it. Programmers can write the higher-level application code independently of whatever specific hardware the end-user is using.įor example, a high-level application for interacting with a serial port may simply have two functions for “send data” and “receive data.” At a lower level, a device driver implementing these functions would communicate to the particular serial port controller installed on a user’s computer. They usually provide the interrupt handling required for any necessary asynchronous time-dependent hardware interface. Drivers are hardware-dependent and operating-system-specific. Once the device sends data back to the driver, the driver may invoke routines in the original calling program. When a calling program invokes a routine in the driver, the driver issues commands to the device. A driver provides a software interface to hardware devices, enabling operating systems and other computer programs to access hardware functions without needing to know precise details of the hardware being used.Ī driver typically communicates with the device through the computer bus or communications subsystem to which the hardware connects. In computing, a device driver (commonly referred to as a driver) is a computer program that operates or controls a particular type of device that is attached to a computer.
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