intro —
introduction to i386 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 i386 (PC-clone) platform.
  Software support for these devices comes 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
    x86/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:
  - com(4)
- NS8250-, NS16450-, and NS16550-based asynchronous serial communications
      device interface
- x86/lpt(4)
- Parallel port device interface
- x86/fdc(4)
- Standard NEC 765 floppy disk controller.
- mca(4)
- MCA I/O bus.
- x86/mem(4)
- Main memory interface
- pci(4)
- PCI I/O bus.
- eisa(4)
- EISA I/O bus, either as main bus or via PCI-EISA bridge.
- isa(4)
- ISA bus and ISA devices, either as main bus or via PCI-ISA bridge.
- isa(4)
- isa I/O bus.
- isapnp(4)
- ``bus'' for ISA devices with PnP support.
- speaker(4)
- console speaker device interface
 
PCMCIA devices are supported through the
    pcmcia(4) bus and
    associated device drivers.
Cardbus devices are supported through the
    cardbus(4) bus and
    associated device drivers.
USB devices are supported through the
    usb(4) bus and associated
    device drivers.
Console devices using ISA, EISA, or PCI video adaptors and
    standard AT or PS/2 keyboards are supported by the machine independent
    wscons(4) console
  driver.
The i386 intro appeared in NetBSD
  1.0.