Open Sound System

The Open Sound System (OSS) is an interface for making and capturing sound in Unix and Unix-like operating systems. It is based on standard Unix devices system calls (i.e. POSIX read, write, ioctl, etc.). The term also sometimes refers to the software in a Unix kernel that provides the OSS interface; it can be thought of as a device driver (or a collection of device drivers) for sound controller hardware. The goal of OSS is to allow the writing of sound-based applications that are agnostic of the underlying sound hardware.

OSS was created by Hannu Savolainen and is distributed under four license options, three of which are free software licences, thus making OSS free software.

The API is designed to use the traditional Unix framework of open(), read(), write(), and ioctl(), via special devices. For instance, the default device for sound input and output is /dev/dsp. Examples using the shell:

The project was initially free software, but following the project's success, Savolainen was contracted by the company 4Front Technologies and made his support for newer sound devices and improvements proprietary. In response, eventually the Linux community abandoned the OSS/free implementation included in the kernel and development effort switched to the replacement Advanced Linux Sound Architecture (ALSA). Some Linux distributions, such as Ubuntu, have chosen to disable OSS support in their kernels and ignore any bugs filed against OSS4 packages (although OSS support may be re-enabled on Ubuntu).