A device driver, often called a driver for short, is a computer program that is intended to allow another program (typically, an operating system) to interact with a hardware device.
Because of the diversity of modern hardware and operating systems, many ways exist in which drivers can be used. Drivers are used for interfacing with:
- Printers
- Video adapters
- Network cards
- Sound cards
- Local buseses of various sorts - in particular, for bus mastering on modern systems
- Low-bandwidth I/O buses of various sorts (for pointing devices such as mice, keyboards, USB, etc.)
- Hard disk drive buses (ATA, SCSI)
- Implementing support for different file systems
- Implementing support for scanners and digital cameras
- On the hardware side:
- Interfacing directly
- Using some higher-level interface (e.g. Video BIOS)
- Using another lower-level device driver (e.g. file system drivers)
- Simulating work with hardware, while doing something entirely different
- On the software side:
- Allowing the operating system direct access to hardware resources
- Implementing only primitivess
- Implementing an interface for non-driver software (e.g. TWAIN)
- Implementing a language, sometimes quite high-level, e.g. PostScript
All of this means that the people most likely to write device drivers come from the companies that develop the hardware - since they have more complete access to information about the design of their hardware than most outsiders. Moreover, it was traditionally considered in the hardware manufacturer's interest to guarantee that their clients would be able to use their hardware in an optimum way. However, in recent years non-vendors too have written numerous device drivers, mainly for use under free operating systems. In such cases, co-operation on behalf of the vendor is still important, however, as reverse engineering is much more difficult with hardware than it is with software, meaning it may take a long time to learn to operate hardware that has an unknown interface.
See also
External links