SPKR(4)

💖 NAME 💖

Okay bestie, so like, speaker and spkr are literally the same thing — it's the console speaker device driver, and it's giving main character energy on your FreeBSD machine. 💅 No cap, this is the page for spkr(4), the Kernel Interfaces Manual entry. Slay.

✨ SYNOPSIS ✨

device speaker
#include <dev/speaker/speaker.h>

🌸 DESCRIPTION 🌸

Okay so, the speaker device driver lets applications control the PC console speaker on an IBM-PC-compatible machine running FreeBSD. It's literally that simple, and it's iconic.

Only one process can have this device open at any given time, okay? open(2) and close(2) are used to lock and relinquish it. And if you try to open it when another process has it locked, you'll get -1 with an EBUSY error indication — so like, no cap, it's busy. 💀

An attempt to open when another process has the device locked will return -1 with an EBUSY error indication.

Writes to the device are interpreted as play strings in a simple ASCII melody notation. An ioctl(2) request for tone generation at arbitrary frequencies is also supported. Slay.

Sound-generation does not monopolize the processor; in fact, the driver spends most of its time sleeping while the PC hardware is emitting tones. Other processes may emit beeps while the driver is running. So it's lowkey chill, and it's not even a vibe killer.

Applications may call ioctl(2) on a speaker file descriptor to control the speaker driver directly; definitions for the ioctl(2) interface are in <dev/speaker/speaker.h>. The tone_t structure used in these calls has two fields, specifying a frequency (in Hz) and a duration (in 1/100ths of a second). A frequency of zero is interpreted as a rest. Periodt.

At present there are two such ioctl(2) calls. SPKRTONE accepts a pointer to a single tone structure as third argument and plays it. SPKRTUNE accepts a pointer to the first of an array of tone structures and plays them in continuous sequence; this array must be terminated by a final member with a zero duration. So like, one is for a single note, and the other is for a whole melody — iykyk.

The play-string language is modeled on the PLAY statement conventions of IBM Advanced BASIC 2.0. The MB, MF, and X primitives of PLAY are not useful in a timesharing environment and are omitted. The octave-tracking feature and the slur mark are new. Obsessed with the new features, honestly.

There are 84 accessible notes numbered 1-84 in 7 octaves, each running from C to B, numbered 0-6; the scale is equal-tempered A440 and octave 3 starts with middle C. By default, the play function emits half-second notes with the last 1/16th second being rest time. So like, the default is a little half-second bop with a tiny rest at the end — it's giving rhythm.

Play strings are interpreted left to right as a series of play command groups; letter case is ignored. Play command groups are as follows:

• CDEFGAB — Letters A through G cause the corresponding note to be played in the current octave. A note letter may optionally be followed by an “accidental sign”, one of #, +, or -; the first two of these cause it to be sharped one half-tone, the last causes it to be flatted one half-tone. It may also be followed by a time value number and by sustain dots (see below). Time values are interpreted as for the L command below. So like, you can write C# or D- and it's fine.
• O n — If n is numeric, this sets the current octave. n may also be one of L or N to enable or disable octave-tracking (it is disabled by default). When octave-tracking is on, interpretation of a pair of letter notes will change octaves if necessary in order to make the smallest possible jump between notes. Thus ``olbc'' will be played as ``olb>c'', and ``olcb'' as ``olc<b''. Octave locking is disabled for one letter note following >, <, and O[0123456]. (The octave-locking feature is not supported in IBM BASIC.) This is like the smart octave feature, and it's lowkey genius.
• > — Bump the current octave up one. Literally just go up.
• < — Drop the current octave down one. And down.
• N n — Play note n, n being 1 to 84 or 0 for a rest of current time value. May be followed by sustain dots. So you can play by number, not just letter. Ngl, that's convenient.
• L n — Sets the current time value for notes. The default is L4, quarter or crotchet notes. The lowest possible value is 1; values up to 64 are accepted. L1 sets whole notes, L2 sets half notes, L4 sets quarter notes, etc. So like, L4 is the default queen.
• P n — Pause (rest), with n interpreted as for L n. May be followed by sustain dots. May also be written ~. So you can pause with a P or a ~, and it's cute.
• T n — Sets the number of quarter notes per minute; default is 120. Musical names for common tempi are:
  • very slow: Larghissimo, Largo (40-60), Larghetto (60-66), Grave, Lento, Adagio (66-76)
  • slow: Adagietto, Andante (76-108)
  • medium: Andantino, Moderato (108-120)
  • fast: Allegretto, Allegro (120-168), Vivace, Veloce, Presto (168-208)
  • very fast: Prestissimo So like, you can set the tempo by BPM or by the vibe name. Slay.
• M[LNS] — Set articulation. MN (N for normal) is the default; the last 1/8th of the note's value is rest time. You can set ML for legato (no rest space) or MS for staccato (1/4 rest space). So like, normal, legato, or staccato — pick your vibe.

Notes (that is, CDEFGAB or N command character groups) may be followed by sustain dots. Each dot causes the note's value to be lengthened by one-half for each one. Thus, a note dotted once is held for 3/2 of its undotted value; dotted twice, it is held 9/4, and three times would give 27/8. So like, the more dots, the longer you hold it — it's giving drama.

A note and its sustain dots may also be followed by a slur mark (underscore). This causes the normal micro-rest after the note to be filled in, slurring it to the next one. (The slur feature is not supported in IBM BASIC.) So like, no rest, just smooth transition — it's a slur, periodt.

Whitespace in play strings is simply skipped and may be used to separate melody sections. So like, use spaces to make it readable, bestie.

🎀 FILES 🎀

• /dev/speaker — speaker device file

🦋 SEE ALSO 🦋

• spkrtest(8)

🌈 HISTORY 🌈

The speaker device appeared in FreeBSD 1.0. So it's literally been around forever — iconic.

💜 AUTHORS 💜

Eric S. Raymond <esr@snark.thyrsus.com>, June 1990

🌸 PORTED BY 🌸

Andrew A. Chernov <ache@astral.msk.su>

😭 BUGS 😭

Due to roundoff in the pitch tables and slop in the tone-generation and timer hardware (neither of which was designed for precision), neither pitch accuracy nor timings will be mathematically exact. There is no volume control. 💀

So like, it's not going to be perfect, okay? It's a PC speaker, not a symphony orchestra. And no, you can't change the volume — it's literally just beep boop at one level.

The action of two or more sustain dots does not reflect standard musical notation, in which each dot adds half the value of the previous dot modifier, not half the value of the note as modified. Thus, a note dotted once is held for 3/2 of its undotted value; dotted twice, it is held 7/4, and three times would give 15/8. The multiply-by-3/2 interpretation, however, is specified in the IBM BASIC manual and has been retained for compatibility. So like, it's a whole thing.

In play strings which are very long (longer than your system's physical I/O blocks) note suffixes or numbers may occasionally be parsed incorrectly due to crossing a block boundary. So yeah, watch out for that — don't write a novel-length play string.

---

XOXO, this page was brought to you by the Debian crew on November 10, 2005 — periodt. 💖