intro —
introduction to dreamcast special files and hardware
  support
This section describes the special files, related driver functions, and
  networking support available in the system. In this part of the manual, the
  SYNOPSIS section of each configurable device gives a sample specification for
  use in constructing a system description for the
  config(1) program. The
  DIAGNOSTICS section lists messages which may appear on the console and/or in
  the system error log /var/log/messages due to errors
  in device operation; see
  syslogd(8) for more
  information.
This section contains both devices which may be configured into
    the system and network related information. The networking support is
    introduced in
    netintro(4).
This section describes the hardware supported on the Dreamcast platform.
  Software support for these devices come in two forms. A hardware device may be
  supported with a character or block device driver, or it may
  be used within the networking subsystem and have a network
  interface driver. Block and character devices are accessed through files
  in the file system of a special type; see
  mknod(8). Network interfaces
  are indirectly accessed through the interprocess communication facilities
  provided by the system; see
  socket(2).
A hardware device is identified to the system at configuration
    time and the appropriate device or network interface driver is then compiled
    into the system. When the resultant system is booted, the autoconfiguration
    facilities in the system probe for the device and, if found, enable the
    software support for it. If a device does not respond at autoconfiguration
    time, it is not accessible at any time afterwards. To enable a device which
    did not autoconfigure, the system must be rebooted.
The autoconfiguration system is described in
    autoconf(4). A list of
    the supported devices is given below.
The devices listed below are supported in this incarnation of the system.
  Devices are indicated by their functional interface. Not all supported devices
  are listed.
Standard builtin devices:
  - g2bus
- “G2” internal I/O bus
- gapspci
- PCI bridge used in expansion port peripherals
- gdrom
- Builtin GD-ROM optical disc drive
- pvr
- Framebuffer device using the builtin NEC PVR graphics subsystem
- aica
- Builtin AICA sound system
 
Controller port peripherals are supported though the
    dreamcast/maple(4)
    bus and associated device drivers.
Network interfaces:
  - rtk
- Ethernet driver for the HIT-0400 Broadband Adapter
- mbe
- Ethernet driver for the HIT-0300 LAN Adapter
 
The intro man page appeared in NetBSD
  2.0.