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In
computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes, and development of both hardware and software. Computing has scientific, ...
, a device driver is a
computer program A computer program is a sequence or set of instructions in a programming language for a computer to Execution (computing), execute. Computer programs are one component of software, which also includes software documentation, documentation and oth ...
that operates or controls a particular type of device that is attached to a
computer A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations ( computation) automatically. Modern digital electronic computers can perform generic sets of operations known as programs. These prog ...
or
automaton An automaton (; plural: automata or automatons) is a relatively self-operating machine, or control mechanism designed to automatically follow a sequence of operations, or respond to predetermined instructions.Automaton – Definition and More ...
. A driver provides a software
interface Interface or interfacing may refer to: Academic journals * ''Interface'' (journal), by the Electrochemical Society * '' Interface, Journal of Applied Linguistics'', now merged with ''ITL International Journal of Applied Linguistics'' * '' Int ...
to hardware devices, enabling
operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ef ...
s 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 In computer architecture, a bus (shortened form of the Latin '' omnibus'', and historically also called data highway or databus) is a communication system that transfers data between components inside a computer, or between computers. This e ...
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 In digital computers, an interrupt (sometimes referred to as a trap) is a request for the processor to ''interrupt'' currently executing code (when permitted), so that the event can be processed in a timely manner. If the request is accepted, ...
handling required for any necessary asynchronous time-dependent hardware interface.


Purpose

The main purpose of device drivers is to provide abstraction by acting as a translator between a hardware device and the applications or
operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ef ...
s that use it. 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 In computing, a serial port is a serial communication interface through which information transfers in or out sequentially one bit at a time. This is in contrast to a parallel port, which communicates multiple bits simultaneously in parallel. ...
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 Future Technology Devices International Limited, commonly known by its acronym FTDI, is a Scottish privately held semiconductor device company, specialising in Universal Serial Bus (USB) technology. It develops, manufactures, and supports dev ...
serial port converter, but each hardware-specific device driver
abstracts An abstract is a brief summary of a research article, thesis, review, conference proceeding, or any in-depth analysis of a particular subject and is often used to help the reader quickly ascertain the paper's purpose. When used, an abstract always ...
these details into the same (or similar) software interface.


Development

Writing a device driver requires an in-depth understanding of how the hardware and the software works for a given
platform Platform may refer to: Technology * Computing platform, a framework on which applications may be run * Platform game, a genre of video games * Car platform, a set of components shared by several vehicle models * Weapons platform, a system or ...
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 system An operating system (OS) is system software that manages computer hardware, software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ef ...
s can be stopped without greatly affecting the rest of the system. Even drivers executing in
user mode A modern computer operating system usually segregates virtual memory into user space and kernel space. Primarily, this separation serves to provide memory protection and hardware protection from malicious or errant software behaviour. Kernel ...
can crash a system if the device is erroneously programmed. These factors make it more difficult and dangerous to diagnose problems. The task of writing drivers thus usually falls to
software engineer Software engineering is a systematic engineering approach to software development. A software engineer is a person who applies the principles of software engineering to design, develop, maintain, test, and evaluate computer software. The term ''p ...
s or
computer engineer Computer engineering (CoE or CpE) is a branch of electrical engineering and computer science that integrates several fields of computer science and electronic engineering required to develop computer hardware and computer software, software. C ...
s 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 Manufacturing is the creation or production of goods with the help of equipment, labor, machines, tools, and chemical or biological processing or formulation. It is the essence of secondary sector of the economy. The term may refer to ...
's interest to guarantee that their clients can use their hardware in an optimum way. Typically, the
Logical Device Driver Logic is the study of correct reasoning. It includes both formal and informal logic. Formal logic is the science of deductively valid inferences or of logical truths. It is a formal science investigating how conclusions follow from premis ...
(LDD) is written by the operating system vendor, while the
Physical Device Driver Physical may refer to: *Physical examination In a physical examination, medical examination, or clinical examination, a medical practitioner examines a patient for any possible medical signs or symptoms of a medical condition. It generally co ...
(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 Free and open-source software (FOSS) is a term used to refer to groups of software consisting of both free software and open-source software where anyone is freely licensed to use, copy, study, and change the software in any way, and the source ...
operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ef ...
s. 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 Reverse engineering (also known as backwards engineering or back engineering) is a process or method through which one attempts to understand through deductive reasoning how a previously made device, process, system, or piece of software accompli ...
, this is much more difficult with hardware than it is with software.
Microsoft Microsoft Corporation is an American multinational technology corporation producing computer software, consumer electronics, personal computers, and related services headquartered at the Microsoft Redmond campus located in Redmond, Washi ...
has attempted to reduce system instability due to poorly written device drivers by creating a new framework for driver development, called
Windows Driver Frameworks Windows Driver Frameworks (WDF, formerly Windows Driver Foundation), is a set of Microsoft tools and libraries that aid in the creation of device drivers for Windows 2000 and later versions of Windows. It complements Windows Driver Model, abstract ...
(WDF). This includes
User-Mode Driver Framework User-Mode Driver Framework (UMDF) is a device-driver development platform first introduced with Microsoft's Windows Vista operating system, and is also available for Windows XP. It facilitates the creation of drivers for certain classes of device ...
(UMDF) that encourages development of certain types of drivers—primarily those that implement a
message-based protocol In computer science, message passing is a technique for invoking behavior (i.e., running a program) on a computer. The invoking program sends a message to a process (which may be an actor or object) and relies on that process and its supporting ...
for communicating with their devices—as user-mode drivers. If such drivers malfunction, they do not cause system instability. The
Kernel-Mode Driver Framework The Kernel-Mode Driver Framework (KMDF) is a driver framework developed by Microsoft as a tool to aid driver developers create and maintain kernel mode device drivers for Windows 2000 and later releases. It is one of the frameworks included in t ...
(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 An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple trees are cultivated worldwide and are the most widely grown species in the genus '' Malus''. The tree originated in Central Asia, where its wild ancest ...
has an open-source framework for developing drivers on
macOS macOS (; previously OS X and originally Mac OS X) is a Unix operating system developed and marketed by Apple Inc. since 2001. It is the primary operating system for Apple's Mac computers. Within the market of desktop and la ...
, called I/O Kit. In
Linux Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, whi ...
environments, programmers can build device drivers as parts of the
kernel Kernel may refer to: Computing * Kernel (operating system), the central component of most operating systems * Kernel (image processing), a matrix used for image convolution * Compute kernel, in GPGPU programming * Kernel method, in machine learn ...
, separately as loadable
module Module, modular and modularity may refer to the concept of modularity. They may also refer to: Computing and engineering * Modular design, the engineering discipline of designing complex devices using separately designed sub-components * Modul ...
s, 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 In computing, a parallel port is a type of interface found on early computers ( personal and otherwise) for connecting peripherals. The name refers to the way the data is sent; parallel ports send multiple bits of data at once ( parall ...
), hd (disk), loop, and sound (these include
mixer Mixer may refer to: Electronics * DJ mixer, a type of audio mixing console used by disc jockeys * Electronic mixer, electrical circuit for adding signal voltages * Frequency mixer, electrical circuit that creates new frequencies from two signals ...
,
sequencer Sequencer may refer to: Technology * Drum sequencer (controller), an electromechanical system for controlling a sequence of events automatically * DNA sequencer, a machine used to automatically produce a sequence readout from a biological DNA sam ...
, dsp, and audio).
Microsoft Windows Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for ...
.sys .sys is a filename extension used in MS-DOS applications and Microsoft Windows operating systems. They are system files that contain device drivers or hardware configurations for the system. Most DOS files are real mode device drivers. Certain ...
files and
Linux Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, whi ...
.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.


Kernel mode vs. user mode

Device drivers, particularly on
Microsoft Windows Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for ...
platforms, can run in
kernel-mode In computer science, hierarchical protection domains, often called protection rings, are mechanisms to protect data and functionality from faults (by improving fault tolerance) and malicious behavior (by providing computer security). Compu ...
( Ring 0 on x86 CPUs) or in
user-mode In computer science, hierarchical protection domains, often called protection rings, are mechanisms to protect data and functionality from faults (by improving fault tolerance) and malicious behavior (by providing computer security). Comput ...
(Ring 3 on x86 CPUs). 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. 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.


Applications

Because of the diversity of hardware and operating systems, drivers operate in many different environments. Drivers may
interface Interface or interfacing may refer to: Academic journals * ''Interface'' (journal), by the Electrochemical Society * '' Interface, Journal of Applied Linguistics'', now merged with ''ITL International Journal of Applied Linguistics'' * '' Int ...
with: * Printers *
Video adapters A graphics card (also called a video card, display card, graphics adapter, VGA card/VGA, video adapter, display adapter, or mistakenly GPU) is an expansion card which generates a feed of output images to a display device, such as a computer moni ...
* Network cards *
Sound card A sound card (also known as an audio card) is an internal expansion card that provides input and output of audio signals to and from a computer under the control of computer programs. The term ''sound card'' is also applied to external audio ...
s * Local
buses A bus (contracted from omnibus, with variants multibus, motorbus, autobus, etc.) is a road vehicle that carries significantly more passengers than an average car or van. It is most commonly used in public transport, but is also in use for cha ...
of various sorts—in particular, for
bus mastering In computing, bus mastering is a feature supported by many bus architectures that enables a device connected to the bus to initiate direct memory access (DMA) transactions. It is also referred to as first-party DMA, in contrast with third-party ...
on modern systems * Low-
bandwidth Bandwidth commonly refers to: * Bandwidth (signal processing) or ''analog bandwidth'', ''frequency bandwidth'', or ''radio bandwidth'', a measure of the width of a frequency range * Bandwidth (computing), the rate of data transfer, bit rate or thr ...
I/O buses of various sorts (for
pointing device A pointing device is a human interface device that allows a user to input spatial (i.e., continuous and multi-dimensional) data to a computer. CAD systems and graphical user interfaces (GUI) allow the user to control and provide data to ...
s such as
mice A mouse ( : mice) is a small rodent. Characteristically, mice are known to have a pointed snout, small rounded ears, a body-length scaly tail, and a high breeding rate. The best known mouse species is the common house mouse (''Mus musculus'' ...
,
keyboard Keyboard may refer to: Text input * Keyboard, part of a typewriter * Computer keyboard ** Keyboard layout, the software control of computer keyboards and their mapping ** Keyboard technology, computer keyboard hardware and firmware Music * Mu ...
s, etc.) *
Computer storage Computer data storage is a technology consisting of computer components and recording media that are used to retain digital data. It is a core function and fundamental component of computers. The central processing unit (CPU) of a compute ...
devices such as
hard disk A hard disk drive (HDD), hard disk, hard drive, or fixed disk is an electro-mechanical data storage device that stores and retrieves digital data using magnetic storage with one or more rigid rapidly rotating platters coated with magn ...
,
CD-ROM A CD-ROM (, compact disc read-only memory) is a type of read-only memory consisting of a pre-pressed optical compact disc that contains data. Computers can read—but not write or erase—CD-ROMs. Some CDs, called enhanced CDs, hold both com ...
, and
floppy disk A floppy disk or floppy diskette (casually referred to as a floppy, or a diskette) is an obsolescent type of disk storage composed of a thin and flexible disk of a magnetic storage medium in a square or nearly square plastic enclosure lined ...
buses ( ATA,
SATA SATA (Serial AT Attachment) is a computer bus interface that connects host bus adapters to mass storage devices such as hard disk drives, optical drives, and solid-state drives. Serial ATA succeeded the earlier Parallel ATA (PATA) standard t ...
,
SCSI Small Computer System Interface (SCSI, ) is a set of standards for physically connecting and transferring data between computers and peripheral devices. The SCSI standards define commands, protocols, electrical, optical and logical interface ...
, SAS) * Implementing support for different
file system In computing, file system or filesystem (often abbreviated to fs) is a method and data structure that the operating system uses to control how data is stored and retrieved. Without a file system, data placed in a storage medium would be one larg ...
s *
Image scanner An image scanner—often abbreviated to just scanner—is a device that optically scans images, printed text, handwriting or an object and converts it to a digital image. Commonly used in offices are variations of the desktop ''flatbed scanner'' ...
s *
Digital camera A digital camera is a camera that captures photographs in digital memory. Most cameras produced today are digital, largely replacing those that capture images on photographic film. Digital cameras are now widely incorporated into mobile devices ...
s * Digital terrestrial television tuners * Radio frequency communication transceiver adapters for wireless personal area networks as used for short-distance and low-rate wireless communication in home automation, (such as example Bluetooth Low Energy (BLE), Thread,
ZigBee Zigbee is an IEEE 802.15.4-based specification for a suite of high-level communication protocols used to create personal area networks with small, low-power digital radios, such as for home automation, medical device data collection, and oth ...
, and
Z-Wave Z-Wave is a wireless communications protocol used primarily for residential and commercial building automation. It is a mesh network using low-energy radio waves to communicate from device to device, allowing for wireless control of smart home de ...
). *
IrDA The Infrared Data Association (IrDA) is an industry-driven interest group that was founded in 1994 by around 50 companies. IrDA provides specifications for a complete set of protocols for wireless infrared communications, and the name "IrDA" also ...
adapters Common levels of abstraction for device drivers include: * For hardware: ** Interfacing directly ** Writing to or reading from a
device control register In computing, a device control register is a hardware register that controls some computer hardware device, for example a peripheral or an expansion card. Specific technologies use this terminology with a narrower meaning: * The ISA PNP specifica ...
** Using some higher-level interface (e.g. Video BIOS) ** Using another lower-level device driver (e.g. file system drivers using disk drivers) ** Simulating work with hardware, while doing something entirely different * For software: ** Allowing the operating system direct access to hardware resources ** Implementing only primitives ** Implementing an interface for non-driver software (e.g.
TWAIN Twain may refer to: People * Mark Twain, pen name of American writer Samuel Langhorne Clemens (1835–1910) * Norman Twain (1930–2016), American film producer * Shania Twain (born 1965), Canadian singer-songwriter Places * Twain, California, a ...
) ** Implementing a language, sometimes quite high-level (e.g.
PostScript PostScript (PS) is a page description language in the electronic publishing and desktop publishing realm. It is a dynamically typed, concatenative programming language. It was created at Adobe Systems by John Warnock, Charles Geschke, Do ...
) So choosing and installing the correct device drivers for given hardware is often a key component of computer system configuration.


Virtual device drivers

Virtual device drivers represent a particular variant of device drivers. They are used to emulate a hardware device, particularly in
virtualization In computing, virtualization or virtualisation (sometimes abbreviated v12n, a numeronym) is the act of creating a virtual (rather than actual) version of something at the same abstraction level, including virtual computer hardware platforms, stor ...
environments, for example when a
DOS DOS is shorthand for the MS-DOS and IBM PC DOS family of operating systems. DOS may also refer to: Computing * Data over signalling (DoS), multiplexing data onto a signalling channel * Denial-of-service attack (DoS), an attack on a communicat ...
program is run on a
Microsoft Windows Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for ...
computer or when a guest
operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ef ...
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 In computing, a virtual machine (VM) is the virtualization/ emulation of a computer system. Virtual machines are based on computer architectures and provide functionality of a physical computer. Their implementations may involve specialized h ...
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
interrupt In digital computers, an interrupt (sometimes referred to as a trap) is a request for the processor to ''interrupt'' currently executing code (when permitted), so that the event can be processed in a timely manner. If the request is accepted, ...
s into the virtual machine. Virtual devices may also operate in a non-virtualized environment. For example, a virtual
network adapter A network interface controller (NIC, also known as a network interface card, network adapter, LAN adapter or physical network interface, and by similar terms) is a computer hardware component that connects a computer to a computer network. Ear ...
is used with a
virtual private network A virtual private network (VPN) extends a private network across a public network and enables users to send and receive data across shared or public networks as if their computing devices were directly connected to the private network. The b ...
, while a virtual disk device is used with
iSCSI Internet Small Computer Systems Interface or iSCSI ( ) is an Internet Protocol-based storage networking standard for linking data storage facilities. iSCSI provides block-level access to storage devices by carrying SCSI commands over a TCP/IP ...
. A good example for virtual device drivers can be
Daemon Tools DAEMON Tools is a virtual drive and optical disc authoring program for Microsoft Windows and Mac OS. Overview DAEMON tools was originally a successor of ''Generic SafeDisc emulator'' and incorporated all of its features. The program claims ...
. There are several variants of virtual device drivers, such as VxDs, VLMs, and VDDs.


Open source drivers

* Graphics device driver * Printers:
CUPS CUPS (formerly an acronym for Common UNIX Printing System) is a modular printing system for Unix-like computer operating systems which allows a computer to act as a print server. A computer running CUPS is a host that can accept print job ...
* RAIDs: CCISS (Compaq Command Interface for SCSI-3 Support) * Scanners: SANE * Video:
Vidix VIDIX (video interface for *nix) is a portable programming interface for Unix-like operating systems that allows video card drivers running in user space to directly access the framebuffer through Direct Graphics Access extension to the X Win ...
,
Direct Rendering Infrastructure The Direct Rendering Infrastructure (DRI) is the framework comprising the modern Linux graphics stack which allows unprivileged user-space programs to issue commands to graphics hardware without conflicting with other programs. The main use ...
Solaris descriptions of commonly used device drivers: * fas: Fast/wide SCSI controller * hme: Fast (10/100 Mbit/s) Ethernet * isp: Differential SCSI controllers and the SunSwift card * glm: (Gigabaud Link Module) UltraSCSI controllers * scsi: Small Computer Serial Interface (SCSI) devices * sf: soc+ or social Fiber Channel Arbitrated Loop (FCAL) * soc: SPARC Storage Array (SSA) controllers and the control device * social: Serial optical controllers for FCAL (soc+)


APIs

*
Windows Display Driver Model Windows Display Driver Model (WDDM) is the graphic driver architecture for video card drivers running Microsoft Windows versions beginning with Windows Vista. It is a replacement for the previous Windows 2000 and Windows XP display driver model ...
(WDDM) – the graphic display driver architecture for
Windows Vista Windows Vista is a major release of the Windows NT operating system developed by Microsoft. It was the direct successor to Windows XP, which was released five years before, at the time being the longest time span between successive releases of ...
and later. * Unified Audio Model (UAM) *
Windows Driver Foundation Windows Driver Frameworks (WDF, formerly Windows Driver Foundation), is a set of Microsoft tools and libraries that aid in the creation of device drivers for Windows 2000 and later versions of Windows. It complements Windows Driver Model, abstrac ...
(WDF) * Declarative Componentized Hardware (DCH) -
Universal Windows Platform Universal Windows Platform (UWP) is a computing platform created by Microsoft and first introduced in Windows 10. The purpose of this platform is to help develop universal apps that run on Windows 10, Windows 10 Mobile (discontinued), Windo ...
driver *
Windows Driver Model In computing, the Windows Driver Model (WDM) also known at one point as the Win32 Driver Model is a framework for device drivers that was introduced with Windows 98 and Windows 2000 to replace VxD, which was used on older versions of Windows such ...
(WDM) * Network Driver Interface Specification (NDIS) – a standard
network card A network interface controller (NIC, also known as a network interface card, network adapter, LAN adapter or physical network interface, and by similar terms) is a computer hardware component that connects a computer to a computer network. Ear ...
driver API *
Advanced Linux Sound Architecture Advanced Linux Sound Architecture (ALSA) is a software framework and part of the Linux kernel that provides an application programming interface (API) for sound card device drivers. Some of the goals of the ALSA project at its inception wer ...
(ALSA) – the standard Linux sound-driver interface * Scanner Access Now Easy (SANE) – a public-domain interface to raster-image scanner-hardware *
Installable File System The Installable File System (IFS) is a filesystem API in MS-DOS/PC DOS 4.x, IBM OS/2 and Microsoft Windows that enables the operating system to recognize and load drivers for file systems. History When IBM and Microsoft were co-developing OS ...
(IFS) – a filesystem API for IBM OS/2 and Microsoft Windows NT *
Open Data-Link Interface The Open Data-Link Interface (ODI), developed by Apple and Novell, serves the same function as Microsoft and 3COM's Network Driver Interface Specification (NDIS). Originally, ODI was written for NetWare and Macintosh environments. Like NDIS, ODI p ...
(ODI) – network card API similar to NDIS *
Uniform Driver Interface The Uniform Driver Interface (UDI) is a defunct project developed by several companies to define a portable interface for device drivers. The Uniform Driver Interface (UDI) allowed device drivers to be portable across both hardware platforms and op ...
(UDI) – a cross-platform driver interface project * Dynax Driver Framework (dxd) – C++ open source cross-platform driver framework for KMDF and IOKit


Identifiers

A device on the
PCI bus PCI may refer to: Business and economics * Payment card industry, businesses associated with debit, credit, and other payment cards ** Payment Card Industry Data Security Standard, a set of security requirements for credit card processors * Prov ...
or USB is identified by two IDs which consist of 4
hexadecimal In mathematics and computing, the hexadecimal (also base-16 or simply hex) numeral system is a positional numeral system that represents numbers using a radix (base) of 16. Unlike the decimal system representing numbers using 10 symbols, he ...
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.


Security

Devices often have a large number of diverse and customized device drivers running in their operating system (OS) kernel and often contain various bugs and
vulnerabilities Vulnerability refers to "the quality or state of being exposed to the possibility of being attacked or harmed, either physically or emotionally." A window of vulnerability (WOV) is a time frame within which defensive measures are diminished, com ...
, making them a target for exploits. ''Bring Your Own Vulnerable Driver'' (BYOVD) uses signed, old drivers that contain flaws that allow hackers to insert malicious code into the kernel. There is a lack of effective kernel vulnerability detection tools, especially for closed-source OSes such as Microsoft Windows where the source code of the device drivers is mostly not public (open source) and the drivers often also have many privileges. Such vulnerabilities also exist in drivers in laptops, drivers for WiFi and bluetooth, gaming/graphics drivers, and drivers in printers. A group of security researchers considers the lack of isolation as one of the main factors undermining kernel security, and published a isolation framework to protect operating system kernels, primarily the monolithic
Linux kernel The Linux kernel is a free and open-source, monolithic, modular, multitasking, Unix-like operating system kernel. It was originally authored in 1991 by Linus Torvalds for his i386-based PC, and it was soon adopted as the kernel for the GNU ...
which, according to them, gets ~80,000 commits/year to its drivers.


See also

*
Driver (software) A driver in software provides a programming interface to control and manage specific lower level interfaces that are often linked to a specific type of hardware, or other low-level service. In the case of hardware, the specific subclass of drivers ...
*
Class driver {{inline, date=May 2015 In computing, a class driver is a type of hardware device driver that can operate a large number of different devices of a broadly similar type. Class drivers are very often used with USB based devices, which share the esse ...
* Device driver synthesis and verification *
Driver wrapper A driver wrapper is a Wrapper function, subroutine in a software library that functions as an adapter pattern, adapter between an operating system and a driver, such as a device driver, that was not designed for that operating system. It can enable ...
*
Free software Free software or libre software is computer software distributed under terms that allow users to run the software for any purpose as well as to study, change, and distribute it and any adapted versions. Free software is a matter of liberty, n ...
*
Firmware In computing, firmware is a specific class of computer software that provides the low-level control for a device's specific hardware. Firmware, such as the BIOS of a personal computer, may contain basic functions of a device, and may provide h ...
*
Loadable kernel module In computing, a loadable kernel module (LKM) is an object file that contains code to extend the running kernel, or so-called ''base kernel'', of an operating system. LKMs are typically used to add support for new hardware (as device drivers) and ...
* Makedev *
Microcontroller A microcontroller (MCU for ''microcontroller unit'', often also MC, UC, or μC) is a small computer on a single VLSI integrated circuit (IC) chip. A microcontroller contains one or more CPUs ( processor cores) along with memory and programmabl ...
*
Open-source hardware Open-source hardware (OSH) consists of physical artifacts of technology designed and offered by the open-design movement. Both free and open-source software (FOSS) and open-source hardware are created by this open-source culture movement and a ...
*
Printer driver In computers, a printer driver or a print processor is a piece of software on a computer that converts the data to be printed to a format that a printer can understand. The purpose of printer drivers is to allow applications to do printing without ...
* Replicant (operating system) *
udev udev (userspace ) is a device manager for the Linux kernel. As the successor of devfsd and hotplug, udev primarily manages device nodes in the directory. At the same time, udev also handles all user space events raised when hardware devices ...
(userspace /dev)


References


External links


Windows Hardware Dev Center

Linux Hardware Compatibility Lists and Linux Drivers

Understanding Modern Device Drivers(Linux)

BinaryDriverHowto, Ubuntu.

Linux Drivers Source
{{DEFAULTSORT:Device Driver Linux drivers Computing terminology Windows NT kernel