Applications

Because of the diversity of modernupdate hardware and operating systems, drivers operate in many different environments. Drivers may interface with:

• Printers
• Video adapters
• Network cards
• Sound cards
• Local buses 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, etc.)
• Computer storage devices such as hard disk, CD-ROM, and floppy disk buses (ATA, SATA, SCSI, SAS)
• Implementing support for different file systems
• Image scanners
• Digital cameras

Common levels of abstraction for device drivers include:

• For hardware:
  • Interfacing directly
  • Writing to or reading from a device control register
  • 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)
  • Implementing a language, sometimes quite high-level (e.g. PostScript)

So choosing and installing the correct device drivers for given hardware is often a key component of computer system configuration.