- Open Sound System audio devices
/dev/dsp is the default audio device in the system. It's connected to the main
speakers and the primary recording source (such as microphone). The system
administrator can set /dev/dsp to be a symbolic link to the desired default
device. The ossinfo utility can be used to list the available audio devices in
/dev/dsp_mmap, /dev/dsp_ac3, /dev/dsp_multich and /dev/dsp_spdifout are default
audio devices for specific applications such as games or media (DVD) players.
OSS 4.0 (and later) will create audio devices under /dev/oss/<device>
directory. For example /dev/oss/sblive0/pcm0 is the first audio device that
belongs to the first Sound Blaster Live! or Audigy card in the system. These
direct devices are used when an application needs to access specific audio
device (instead of the default one).
You can use the ossinfo
(1) utility with the -a
option to get a
list of the available audio devices in the system.
Traditionally OSS has created device files like /dev/dsp0 to /dev/dspN for each
audio device in the system. OSS 4.0 still supports this legacy naming. These
files are symbolic links to the actual device files located under /dev/oss.
(8) utility is used to manage these links and it will be
automatically invoked when OSS is started.
- The /dev/dsp (default() audio device file will be supported
by all OSS implementations and versions.
- The special purpose audio default devices (such as
/dev/dsp_mmap) are only supported by OSS 4.0 and later.
- The legacy audio device files (such as /dev/dsp1) are
supported by all OSS versions and implementations.
- New style audio device files (under /dev/oss) are only
supported by OSS 4.0 and later. However some independent OSS
implementations may only support the legacy naming even they are otherwise
OSS 4.0 compatible.
- /dev/dsp0 doesn't exist in all Linux systems which use
/dev/dsp for the same purpose. In such systems /dev/dsp points to the
first audio device and /dev/dsp1 to the second.
See the Audio Programming section of the OSS Programmer's Guide (DSP(2)) for
- o /dev/dsp
- Default audio device
- o /dev/dsp_mmap
- Default audio device for applications using
- o /dev/dsp_ac3
- Default audio device for applications sending Dolby Digital
(AC3) audio to an external receiver.
- o /dev/dsp_multich
- Default multichannel (4.0-7.1) audio output device
- o /dev/dsp_spdifout
- Default digital audio (S/PDIF) output device
- o /dev/oss/<driver>/pcmN
- Direct access device files for individual audio
- o /dev/dsp0 to /dev/dspN
- Legacy style direct access audio device files.