Updated: 10/11/2021 by Computer Hope Show More commonly known as a driver, a device driver or hardware driver is a group of files that enable one or more hardware devices to communicate with the computer's operating system. Without drivers, the computer could not send and receive data correctly to hardware devices, such as a printer. Hardware devices that are unknown by the operating system or have features unknown by the operating system all require drivers. Below is a list of hardware devices and peripherals that require drivers. What devices may not need driversToday's operating systems have many generic drivers that allow hardware to work at a basic level without needing drivers or software. However, if that device has features unknown to the operating system, it will not work without drivers. For example, you could plug any keyboard into a computer and expect it to work. However, if that keyboard has any special keys or features, they will not work until the drivers are installed. Note The operating systems' generic driver may not be updated as often as the drivers from a hardware manufacturer or computer manufacturer. What happens if a driver is not installed?If the appropriate driver is not installed, the device may not function properly, if at all. With some devices, the device may work, but all of its features may not work. For example, a computer mouse usually works without drivers, but if it has more buttons than the traditional mouse, those extra buttons will not work until the drivers are installed. For Microsoft Windows users, missing drivers may cause a driver conflict or an error in the Device Manager. If problems or conflicts are encountered with drivers, the computer manufacturer or hardware manufacturer releases a driver update to fix the problems. If updated drivers are available, those drivers need to be installed to replace the existing driver code. Can a driver make my computer do more?Installing a driver only makes the hardware installed in the computer function properly. If the correct driver is not installed, installing the latest driver for the hardware can take full advantage of the device. However, you cannot install a driver for hardware not installed in the computer and expect it to make your computer faster or more capable. In other words, installing video card drivers for a video card that's not installed in the computer does not give your computer all the capabilities of that video card. In this example, you'd need the video card hardware and the video card drivers to be installed. Are computer drivers free?Almost all computer and hardware manufacturers provide free drivers, updates, and software for their devices. You can find a list of direct links to all company's pages through our computer driver page. However, companies no longer in business or products that are no longer supported may no longer offer free drivers. In this situation, third-party companies may host and offer drivers but charge for them. Are computer drivers safe?As long the driver you're downloading comes from a reputable source, like the manufacturer of the device, it is considered safe. If you have to download a driver from a third party, it's difficult to know if they've modified the driver code. Unfortunately, like any computer software, drivers can also be infected with viruses and other malware. We recommend having an antivirus installed and running on a computer before you download and install a driver from a third party. What if I download the wrong driver?If you mistakenly download the wrong driver and attempt to install it on your computer, it will fail during the install. However, it's possible to install a driver for a device that does not exist. However, even if this is done, you'd only get errors about the device not being detected or see problems with the non-existent device in Device Manager. Installing the wrong driver on a computer that's working would not cause it to stop working. However, if you removed a working device and then installed the wrong drivers, that may cause problems. Disk driver, DLL, Drivers CD, Hardware terms, INF, Input driver, Instructions, Mouse driver, Network device driver, Patch, Printer driver, Software terms, System software In computing, a device driver is a computer program that operates or controls a particular type of device that is attached to a computer or automaton.[1] 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 about the hardware being used.
A driver communicates with the device through the computer bus or communications subsystem to which the hardware connects. When a calling program invokes a routine in the driver, the driver issues commands to the device (drives it). Once the device sends data back to the driver, the driver may invoke routines in the original calling program. Drivers are hardware dependent and operating-system-specific. They usually provide the interrupt handling required for any necessary asynchronous time-dependent hardware interface.[2] The main purpose of device drivers is to provide abstraction by acting as a translator between a hardware device and the applications or operating systems that use it.[1] Programmers can write higher-level application code independently of whatever specific hardware the end-user is using. For 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. 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. Writing a device driver requires an in-depth understanding of how the hardware and the software works for a given platform function. 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. In contrast, most user-level software on modern operating systems can be stopped without greatly affecting the rest of the system. Even drivers executing in user mode can crash a system if the device is erroneously programmed. These factors make it more difficult and dangerous to diagnose problems.[3] The task of writing drivers thus usually falls to software engineers or computer engineers who work for hardware-development companies. This is because they have better information than most outsiders about the design of their hardware. Moreover, it was traditionally considered in the hardware manufacturer's interest to guarantee that their clients can use their hardware in an optimum way. 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. However, in recent years, non-vendors have written numerous device drivers for proprietary devices, mainly for use with free and open source operating systems. In such cases, it is important that the hardware manufacturer provide information on how the device communicates. Although this information can instead be learned by reverse engineering, this is much more difficult with hardware than it is with software. Microsoft has attempted to reduce system instability due to poorly written device drivers by creating a new framework for driver development, called Windows Driver Frameworks (WDF). This includes User-Mode Driver Framework (UMDF) that encourages development of certain types of drivers—primarily those that implement a message-based protocol for communicating with their devices—as user-mode drivers. If such drivers malfunction, they do not cause system instability. The Kernel-Mode Driver Framework (KMDF) model continues to allow development of kernel-mode device drivers, but attempts to provide standard implementations of functions that are known to cause problems, including cancellation of I/O operations, power management, and plug and play device support. Apple has an open-source framework for developing drivers on macOS, called I/O Kit. In Linux environments, programmers can build device drivers as parts of the kernel, separately as loadable modules, or as user-mode drivers (for certain types of devices where kernel interfaces exist, such as for USB devices). Makedev includes a list of the devices in Linux, including ttyS (terminal), lp (parallel port), hd (disk), loop, and sound (these include mixer, sequencer, dsp, and audio).[4] Microsoft Windows .sys files and Linux .ko files can contain loadable device drivers. The advantage of loadable device drivers is that they can be loaded only when necessary and then unloaded, thus saving kernel memory. Device drivers, particularly on modern[update] Microsoft Windows platforms, can run in kernel-mode (Ring 0 on x86 CPUs) or in user-mode (Ring 3 on x86 CPUs).[5] The primary benefit of running a driver in user mode is improved stability, since a poorly written user-mode device driver cannot crash the system by overwriting kernel memory.[6] On the other hand, user/kernel-mode transitions usually impose a considerable performance overhead, thus making kernel-mode drivers preferred for low-latency networking. Kernel space can be accessed by user module only through the use of system calls. End user programs like the UNIX shell or other GUI-based applications are part of user space. These applications interact with hardware through kernel supported functions. Because of the diversity of modern[update] hardware and operating systems, drivers operate in many different environments.[7] Drivers may interface with:
Common levels of abstraction for device drivers include:
So choosing and installing the correct device drivers for given hardware is often a key component of computer system configuration.[9] Virtual device drivers represent a particular variant of device drivers. They are used to emulate a hardware device, particularly in virtualization environments, for example when a DOS program is run on a Microsoft Windows computer or when a guest operating system is run on, for example, a Xen host. Instead of enabling the guest operating system to dialog with hardware, virtual device drivers take the opposite role and emulates a piece of hardware, so that the guest operating system and its drivers running inside a virtual machine can have the illusion of accessing real hardware. Attempts by the guest operating system to access the hardware are routed to the virtual device driver in the host operating system as e.g., function calls. The virtual device driver can also send simulated processor-level events like interrupts into the virtual machine. Virtual devices may also operate in a non-virtualized environment. For example, a virtual network adapter is used with a virtual private network, while a virtual disk device is used with iSCSI. A good example for virtual device drivers can be Daemon Tools. There are several variants of virtual device drivers, such as VxDs, VLMs, and VDDs.
Solaris descriptions of commonly used device drivers:
A device on the PCI bus or USB is identified by two IDs which consist of 4 hexadecimal numbers each. The vendor ID identifies the vendor of the device. The device ID identifies a specific device from that manufacturer/vendor. A PCI device has often an ID pair for the main chip of the device, and also a subsystem ID pair which identifies the vendor, which may be different from the chip manufacturer.
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