INTRO(4) Device and Network Interfaces INTRO(4)


Intro, intro - introduction to special files


This section describes various device and network interfaces available on
the system. The types of interfaces described include character and block
devices, STREAMS modules, network protocols, file systems, and ioctl
requests for driver subsystems and classes.

This section contains the following major collections:

(4D) The system provides drivers for a variety of hardware devices, such
as disk, magnetic tapes, serial communication lines, mice, and frame
buffers, as well as virtual devices such as pseudo-terminals and

This section describes special files that refer to specific hardware
peripherals and device drivers. STREAMS device drivers are also
described. Characteristics of both the hardware device and the
corresponding device driver are discussed where applicable.

An application accesses a device through that device's special file.
This section specifies the device special file to be used to access
the device as well as application programming interface (API)
information relevant to the use of the device driver. All device
special files are located under the /devices directory. The
/devices directory hierarchy attempts to mirror the hierarchy of
system busses, controllers, and devices configured on the system.
Logical device names for special files in /devices are located under
the /dev directory. Although not every special file under /devices
will have a corresponding logical entry under /dev, whenever
possible, an application should reference a device using the logical
name for the device. Logical device names are listed in the FILES
section of the page for the device in question.

This section also describes driver configuration where applicable.
Many device drivers have a driver configuration file of the form
driver_name.conf associated with them (see driver.conf(5)). The
configuration information stored in the driver configuration file is
used to configure the driver and the device. Driver configuration
files are located in /kernel/drv and /usr/kernel/drv. Driver
configuration files for platform dependent drivers are located in
/platform/`uname -i`/kernel/drv where `uname -i` is the output of
the uname(1) command with the -i option.

Some driver configuration files may contain user configurable
properties. Changes in a driver's configuration file will not take
effect until the system is rebooted or the driver has been removed
and re-added (see rem_drv(8) and add_drv(8)).

(4FS) This section describes the programmatic interface for several file
systems supported by SunOS.

(4I) This section describes ioctl requests which apply to a class of
drivers or subsystems. For example, ioctl requests which apply to
most tape devices are discussed in mtio(4I). Ioctl requests
relevant to only a specific device are described on the man page for
that device. The page for the device in question should still be
examined for exceptions to the ioctls listed in section 4I.

(4M) This section describes STREAMS modules. Note that STREAMS drivers
are discussed in section 4D. streamio(4I) contains a list of ioctl
requests used to manipulate STREAMS modules and interface with the
STREAMS framework. ioctl(2) requests specific to a STREAMS module
will be discussed on the man page for that module.

(4P) This section describes various network protocols available in SunOS.
SunOS supports both socket-based and STREAMS-based network

The Internet protocol family, described in inet(4P), is the primary
protocol family supported by SunOS, although the system can support
a number of others. The raw interface provides low-level services,
such as packet fragmentation and reassembly, routing, addressing,
and basic transport for socket-based implementations. Facilities
for communicating using an Internet-family protocol are generally
accessed by specifying the AF_INET address family when binding a
socket; see socket(3SOCKET) for details.

Major protocols in the Internet family include:

+o The Internet Protocol (IP) itself, which supports the
universal datagram format, as described in ip(4P). This
is the default protocol for SOCK_RAW type sockets within
the AF_INET domain.

+o The Transmission Control Protocol (TCP); see tcp(4P).
This is the default protocol for SOCK_STREAM type sockets.

+o The User Datagram Protocol (UDP); see udp(4P). This is
the default protocol for SOCK_DGRAM type sockets.

+o The Address Resolution Protocol (ARP); see arp(4P).

+o The Internet Control Message Protocol (ICMP); see


ioctl(2), Intro(3), socket(3SOCKET), st(4D), mtio(4I), streamio(4I),
arp(4P), icmp(4P), inet(4P), ip(4P), tcp(4P), udp(4P), driver.conf(5),
add_drv(8), rem_drv(8)

System Administration Guide: IP Services

STREAMS Programming Guide

Writing Device Drivers

illumos March 10, 2023 illumos