MIDI(4)

NAME
midi - device-independent MIDI driver layer

SYNOPSIS
midi* at opl?
midi* at pcppi?
midi* at sb?
midi* at wss?
pseudo-device sequencer

#include <sys/types.h>
#include <sys/midiio.h>

DESCRIPTION
The midi driver provides support for various MIDI peripherals. It provides a uniform programming interface layer above different underlying MIDI hardware drivers. The MIDI hardware can be of many different kinds, e.g., an external synthesizer on a MIDI port (or a serial port), the PC speaker, an internal FM synth, or a wavetable synth.

There are two device file types available for MIDI operation: /dev/rmidiN, and /dev/music. The /dev/rmidiN devices provides raw access to a MIDI device. Data written is sent to the physical device as fast as possible and is uninterpreted. Reading from the device returns data as soon as it becomes available. A moderate amount of buffering is available both for reading and writing. The raw MIDI devices are mostly useful for non realtime operations, such as downloading patches to a device, since it is hard to get the accurate timing needed for quality music from a user program. But the devices can act as a simple patchboard for MIDI devices. For example, a MIDI keyboard could be connected to a synthesizer by the command cat -u /dev/rmidi1 >/dev/rmidi2

The /dev/music device is a MIDI sequencer device. Data sent to and from this device not only contains the information sent to the MIDI device, but also timing information. The kernel will make sure that data is sent to the physical device at the indicated time. The sequencer device uses the /dev/midiN devices internally and they are unavailable when used by the sequencer.

The API for the sequencer device is binary compatible with the OSS sequencer interface.

FILES
/dev/rmidiN
/dev/music
/dev/sequencer

SEE ALSO
audio(4), ioctl(2), midiplay(1), opl(4), ossaudio(3).
For ports using the ISA bus: pcppi(4), sb(4), wss(4).

HISTORY
The midi driver first appeared in NetBSD 1.4.

BUGS
This man page is very incomplete.