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SPKR(4)		       FreeBSD Kernel Interfaces Manual		       SPKR(4)

     speaker, spkr -- console speaker device driver

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

     The speaker device	driver allows applications to control the PC console
     speaker on	an IBM-PC--compatible machine running FreeBSD.

     Only one process may have this device open	at any given time; open(2) and
     close(2) are used to lock and relinquish it.  An attempt to open when an-
     other 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.

     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.

     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.

     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 ac-
     cepts 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.

     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-track-
     ing' feature and the slur mark are	new.

     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'.

     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	fol-
		lowed 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 val-
		ues are	interpreted as for the L command below.

     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 dis-
		abled 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.)

     >		Bump the current octave	up one.

     <		Drop the current octave	down one.

     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.

     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.

     P n	Pause (rest), with n interpreted as for	L n.  May be followed
		by sustain dots.  May also be written ~.

     T n	Sets the number	of quarter notes per minute; default is	120.
		Musical	names for common tempi are:

				      Tempo	      Beats Per	Minute
		      very slow	      Larghissimo
				      Largo	      40-60
				      Larghetto	      60-66
				      Adagio	      66-76
		      slow	      Adagietto
				      Andante	      76-108
		      medium	      Andantino
				      Moderato	      108-120
		      fast	      Allegretto
				      Allegro	      120-168
				      Presto	      168-208
		      very fast	      Prestissimo

     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).

     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 un-
     dotted value; dotted twice, it is held 9/4, and three times would give

     A note and	its sustain dots may also be followed by a slur	mark (under-
     score).  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.)

     Whitespace	in play	strings	is simply skipped and may be used to separate
     melody sections.

     /dev/speaker    speaker device file


     The speaker device	appeared in FreeBSD 1.0.

     Eric S. Raymond <>, June 1990

     Andrew A. Chernov <>

     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.

     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 modi-
     fier, 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

     In	play strings which are very long (longer than your system's physical
     I/O blocks) note suffixes or numbers may occasionally be parsed incor-
     rectly due	to crossing a block boundary.

FreeBSD	13.0		       November	10, 2005		  FreeBSD 13.0


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