Pseudo-devices Supported by NetBSD
Machine-independent pseudo-device and logical drivers
Pseudo-device drivers add enhanced features to real devices, or provide
device-like interfaces to other subsystems. They come in two flavors:
true pseudo-devices (as configured with the `pseudo-device' keyword in
the kernel configuration file) and logical devices (which attach as
children of real devices during the kernel's autoconfiguration phase).
Please note that these pages reflect the state of NetBSD-current. To check
the supported hardware list for a specific release of NetBSD, check
that release's installation notes.
Supported pseudo-device drivers
- Concatenated disk driver (ccd(4)). This pseudo-device provides
a method of combining multiple physical disk components into a single
logical disk. The components are either serially concatenated or
interleaved (a.k.a. striped, RAID-0). This is useful for combining
many small components into a larger, more usable disk, or for
enhancing performance on servers. For mirroring or parity, see
the RAIDframe driver (raid(4)).
- Memory disk driver (md(4)). This pseudo-device provides a
disk-like device in memory, i.e. a `RAM disk'. It has several
modes of operation, including a mode which allows a kernel to
mount an `injected' RAM disk as the root file system, useful
for the install process.
- RAIDframe disk driver (raid(4)). This pseudo-device provides
a RAID level 0, 1, 4, and 5 functionality. Allows combining multiple
physical disk components into RAID sets.
- Random device driver (rnd(4)). This pseudo-device provides
a source of random data (numbers). It has several modes of operation,
and produces the random data by gathering entropy from physical devices
on the system, and processing that entropy with a cryptographic hash
function.
- Vnode disk driver (vnd(4)). This pseudo-device provides a
disk-like interface to regular files. This is particularly useful
for making or reading raw file system and disk images.
Supported logical device drivers
- Audio device driver (audio(4)). This driver provides a consistent
interface to sound hardware, which is backwards-compatible with the
SunOS audio interface. It provides several audio encodings, including
ITU G.711 mu-law, ITU G.711 A-law, signed linear PCM, unsigned linear PCM,
and adaptive differential PCM. Source-code level compatibility with
OSS Audio (previously known as VoxWare) is provided by a user space
library called libossaudio.a. Binary-level
compatibility with OSS Audio is provided for programs running in the Linux
emulation subsystem. The audio(4) driver also provides a mixer interface.
It attaches to hardware devices that fall into the `Sound hardware'
category of the supported hardware lists.
- Unified Workstation Console, WSCONS. This is a set of drivers which
attach as logical children of various input and output devices on
workstations, providing a consistent, event-oriented interface to
the hardware, for easier application development. Drivers in the
WSCONS suite include wsdisplay(4) (which attaches to display
card drivers), wskbd(4) (which attaches to keyboard drivers),
and wsmouse(4) (which attaches to mouse drivers). WSCONS provides
virtual terminals, flexible terminal emulation (including Sun,
VT100, and dumb terminal emulators), and flexible keyboard map support.
WSCONS also provides emulation of the PCVT and SYSCONS console interfaces
(legacy console drivers for 386BSD, NetBSD, and FreeBSD), raw
keyboard compatibility, and compatibility with USL console ioctls,
allowing legacy applications and programs for other systems to work
(such as Doom on direct VGA). The WSCONS drivers
are still under development.
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Hardware Devices Supported by NetBSD