<s>
A	O
sound	B-Device
card	I-Device
(	O
also	O
known	O
as	O
an	O
audio	B-Device
card	I-Device
)	O
is	O
an	O
internal	B-Architecture
expansion	I-Architecture
card	I-Architecture
that	O
provides	O
input	B-General_Concept
and	I-General_Concept
output	I-General_Concept
of	O
audio	O
signals	O
to	O
and	O
from	O
a	O
computer	O
under	O
the	O
control	O
of	O
computer	B-Application
programs	I-Application
.	O
</s>
<s>
The	O
term	O
sound	B-Device
card	I-Device
is	O
also	O
applied	O
to	O
external	O
audio	O
interfaces	O
used	O
for	O
professional	O
audio	O
applications	O
.	O
</s>
<s>
Sound	O
functionality	O
can	O
also	O
be	O
integrated	O
onto	O
the	O
motherboard	B-Device
,	O
using	O
components	O
similar	O
to	O
those	O
found	O
on	O
plug-in	O
cards	O
.	O
</s>
<s>
The	O
integrated	O
sound	O
system	O
is	O
often	O
still	O
referred	O
to	O
as	O
a	O
sound	B-Device
card	I-Device
.	O
</s>
<s>
Sound	B-Algorithm
processing	I-Algorithm
hardware	O
is	O
also	O
present	O
on	O
modern	O
video	B-Device
cards	I-Device
with	O
HDMI	B-Protocol
to	O
output	O
sound	O
along	O
with	O
the	O
video	O
using	O
that	O
connector	O
;	O
previously	O
they	O
used	O
a	O
S/PDIF	O
connection	O
to	O
the	O
motherboard	B-Device
or	O
sound	B-Device
card	I-Device
.	O
</s>
<s>
Typical	O
uses	O
of	O
sound	B-Device
cards	I-Device
or	O
sound	B-Device
card	I-Device
functionality	O
include	O
providing	O
the	O
audio	O
component	O
for	O
multimedia	O
applications	O
such	O
as	O
music	O
composition	O
,	O
editing	O
video	O
or	O
audio	O
,	O
presentation	O
,	O
education	O
and	O
entertainment	O
(	O
games	O
)	O
and	O
video	O
projection	O
.	O
</s>
<s>
Sound	B-Device
cards	I-Device
are	O
also	O
used	O
for	O
computer-based	O
communication	O
such	O
as	O
voice	B-Application
over	I-Application
IP	I-Application
and	O
teleconferencing	O
.	O
</s>
<s>
Sound	B-Device
cards	I-Device
use	O
a	O
digital-to-analog	O
converter	O
(	O
DAC	O
)	O
,	O
which	O
converts	O
recorded	O
or	O
generated	O
digital	O
signal	O
data	O
into	O
an	O
analog	O
format	O
.	O
</s>
<s>
The	O
output	O
signal	O
is	O
connected	O
to	O
an	O
amplifier	O
,	O
headphones	O
,	O
or	O
external	O
device	O
using	O
standard	O
interconnects	B-General_Concept
,	O
such	O
as	O
a	O
TRS	B-Device
phone	I-Device
connector	I-Device
.	O
</s>
<s>
A	O
common	O
external	O
connector	O
is	O
the	O
microphone	B-Application
connector	O
.	O
</s>
<s>
Input	O
through	O
a	O
microphone	B-Application
connector	O
can	O
be	O
used	O
,	O
for	O
example	O
,	O
by	O
speech	B-Application
recognition	I-Application
or	O
voice	B-Application
over	I-Application
IP	I-Application
applications	O
.	O
</s>
<s>
Most	O
sound	B-Device
cards	I-Device
have	O
a	O
line	O
in	O
connector	O
for	O
an	O
analog	O
input	O
from	O
a	O
sound	O
source	O
that	O
has	O
higher	O
voltage	O
levels	O
than	O
a	O
microphone	B-Application
.	O
</s>
<s>
In	O
either	O
case	O
,	O
the	O
sound	B-Device
card	I-Device
uses	O
an	O
analog-to-digital	O
converter	O
to	O
digitize	O
this	O
signal	O
.	O
</s>
<s>
The	O
card	O
may	O
use	O
direct	B-General_Concept
memory	I-General_Concept
access	I-General_Concept
to	O
transfer	O
the	O
samples	O
to	O
and	O
from	O
main	O
memory	O
,	O
from	O
where	O
a	O
recording	O
and	O
playback	O
software	O
may	O
read	O
and	O
write	O
it	O
to	O
the	O
hard	B-Device
disk	I-Device
for	O
storage	O
,	O
editing	O
,	O
or	O
further	O
processing	O
.	O
</s>
<s>
An	O
important	O
sound	B-Device
card	I-Device
characteristic	O
is	O
polyphony	O
,	O
which	O
refers	O
to	O
its	O
ability	O
to	O
process	O
and	O
output	O
multiple	O
independent	O
voices	O
or	O
sounds	O
simultaneously	O
.	O
</s>
<s>
These	O
distinct	O
channels	O
are	O
seen	O
as	O
the	O
number	O
of	O
audio	O
outputs	O
,	O
which	O
may	O
correspond	O
to	O
a	O
speaker	O
configuration	O
such	O
as	O
2.0	O
(	O
stereo	O
)	O
,	O
2.1	O
(	O
stereo	O
and	O
sub	B-Application
woofer	I-Application
)	O
,	O
5.1	O
(	O
surround	O
)	O
,	O
or	O
other	O
configurations	O
.	O
</s>
<s>
Later	O
cards	O
,	O
such	O
as	O
the	O
AdLib	O
sound	B-Device
card	I-Device
,	O
had	O
a	O
9-voice	O
polyphony	O
combined	O
in	O
1	O
mono	O
output	O
channel	O
.	O
</s>
<s>
Early	O
PC	O
sound	B-Device
cards	I-Device
had	O
multiple	O
FM	O
synthesis	O
voices	O
(	O
typically	O
9	O
or	O
16	O
)	O
which	O
were	O
used	O
for	O
MIDI	O
music	O
.	O
</s>
<s>
Modern	O
low-cost	O
integrated	O
sound	B-Device
cards	I-Device
(	O
i.e.	O
,	O
those	O
built	O
into	O
motherboards	B-Device
)	O
such	O
as	O
audio	B-Algorithm
codecs	I-Algorithm
like	O
those	O
meeting	O
the	O
AC'97	O
standard	O
and	O
even	O
some	O
lower-cost	O
expansion	O
sound	B-Device
cards	I-Device
still	O
work	O
this	O
way	O
.	O
</s>
<s>
This	O
is	O
similar	O
to	O
the	O
way	O
inexpensive	O
softmodems	B-Device
perform	O
modem	O
tasks	O
in	O
software	O
rather	O
than	O
in	O
hardware	O
.	O
</s>
<s>
In	O
the	O
early	O
days	O
of	O
wavetable	O
synthesis	O
,	O
some	O
sound	B-Device
card	I-Device
manufacturers	O
advertised	O
polyphony	O
solely	O
on	O
the	O
MIDI	O
capabilities	O
alone	O
.	O
</s>
<s>
In	O
this	O
case	O
,	O
typically	O
,	O
the	O
card	O
is	O
only	O
capable	O
of	O
two	O
channels	O
of	O
digital	O
sound	O
and	O
the	O
polyphony	O
specification	O
solely	O
applies	O
to	O
the	O
number	O
of	O
MIDI	O
instruments	O
the	O
sound	B-Device
card	I-Device
is	O
capable	O
of	O
producing	O
at	O
once	O
.	O
</s>
<s>
Modern	O
sound	B-Device
cards	I-Device
may	O
provide	O
more	O
flexible	O
audio	O
accelerator	O
capabilities	O
which	O
can	O
be	O
used	O
in	O
support	O
of	O
higher	O
levels	O
of	O
polyphony	O
or	O
other	O
purposes	O
such	O
as	O
hardware	O
acceleration	O
of	O
3D	O
sound	O
,	O
positional	B-Application
audio	I-Application
and	O
real-time	O
DSP	B-Architecture
effects	O
.	O
</s>
<s>
Connectors	O
on	O
the	O
sound	B-Device
cards	I-Device
are	O
color-coded	O
as	O
per	O
the	O
PC	O
System	O
Design	O
Guide	O
.	O
</s>
<s>
Sound	B-Device
cards	I-Device
for	O
IBM	O
PC	O
compatible	B-Device
computers	O
were	O
very	O
uncommon	O
until	O
1988	O
.	O
</s>
<s>
For	O
the	O
majority	O
IBM	O
PC	O
users	O
,	O
the	O
internal	O
PC	B-Device
speaker	I-Device
was	O
the	O
only	O
way	O
for	O
early	O
PC	O
software	O
to	O
produce	O
sound	O
and	O
music	O
.	O
</s>
<s>
Several	O
companies	O
,	O
most	O
notably	O
Access	O
Software	O
,	O
developed	O
techniques	O
for	O
digital	O
sound	O
reproduction	O
over	O
the	O
PC	B-Device
speaker	I-Device
like	O
RealSound	O
.	O
</s>
<s>
Early	O
sound	B-Device
cards	I-Device
for	O
the	O
IBM	O
PC	O
platform	O
were	O
not	O
designed	O
for	O
gaming	O
or	O
multimedia	O
applications	O
,	O
but	O
rather	O
on	O
specific	O
audio	O
applications	O
,	O
such	O
as	O
music	O
composition	O
with	O
the	O
AdLib	O
Personal	O
Music	O
System	O
,	O
IBM	B-Device
Music	I-Device
Feature	I-Device
Card	I-Device
,	O
and	O
Creative	O
Music	O
System	O
,	O
or	O
on	O
speech	O
synthesis	O
like	O
Digispeech	O
DS201	O
,	O
Covox	O
Speech	O
Thing	O
,	O
and	O
Street	O
Electronics	O
Echo	O
.	O
</s>
<s>
In	O
1988	O
,	O
a	O
panel	O
of	O
computer-game	O
CEOs	O
stated	O
at	O
the	O
Consumer	O
Electronics	O
Show	O
that	O
the	O
PC	O
's	O
limited	O
sound	O
capability	O
prevented	O
it	O
from	O
becoming	O
the	O
leading	O
home	O
computer	O
,	O
that	O
it	O
needed	O
a	O
$49	O
–	O
79	O
sound	B-Device
card	I-Device
with	O
better	O
capability	O
than	O
current	O
products	O
,	O
and	O
that	O
once	O
such	O
hardware	O
was	O
widely	O
installed	O
,	O
their	O
companies	O
would	O
support	O
it	O
.	O
</s>
<s>
Sierra	O
On-Line	O
,	O
which	O
had	O
pioneered	O
supporting	O
EGA	B-Device
and	O
VGA	B-Protocol
video	O
,	O
and	O
3-1/2	O
"	O
disks	O
,	O
promised	O
that	O
year	O
to	O
support	O
the	O
AdLib	O
,	O
IBM	O
Music	O
Feature	O
,	O
and	O
Roland	O
MT-32	O
sound	B-Device
cards	I-Device
in	O
its	O
games	O
.	O
</s>
<s>
One	O
of	O
the	O
first	O
manufacturers	O
of	O
sound	B-Device
cards	I-Device
for	O
the	O
IBM	O
PC	O
was	O
AdLib	O
,	O
which	O
produced	O
a	O
card	O
based	O
on	O
the	O
Yamaha	O
YM3812	O
sound	O
chip	O
,	O
also	O
known	O
as	O
the	O
OPL2	O
.	O
</s>
<s>
Creative	O
Labs	O
also	O
marketed	O
a	O
sound	B-Device
card	I-Device
about	O
the	O
same	O
time	O
called	O
the	O
Creative	O
Music	O
System	O
(	O
C/MS	O
)	O
.	O
</s>
<s>
It	O
sounded	O
much	O
like	O
twelve	O
simultaneous	O
PC	B-Device
speakers	I-Device
would	O
have	O
except	O
for	O
each	O
channel	O
having	O
amplitude	B-Application
control	O
,	O
and	O
failed	O
to	O
sell	O
well	O
,	O
even	O
after	O
Creative	O
renamed	O
it	O
the	O
Game	O
Blaster	O
a	O
year	O
later	O
,	O
and	O
marketed	O
it	O
through	O
RadioShack	O
in	O
the	O
US	O
.	O
</s>
<s>
The	O
Game	O
Blaster	O
retailed	O
for	O
under	O
$100	O
and	O
was	O
compatible	B-Device
with	O
many	O
popular	O
games	O
,	O
such	O
as	O
Silpheed	B-Device
.	O
</s>
<s>
A	O
large	O
change	O
in	O
the	O
IBM	O
PC	O
compatible	B-Device
sound	B-Device
card	I-Device
market	O
happened	O
when	O
Creative	O
Labs	O
introduced	O
the	O
Sound	B-Application
Blaster	I-Application
card	I-Application
.	O
</s>
<s>
Recommended	O
by	O
Microsoft	O
to	O
developers	O
creating	O
software	O
based	O
on	O
the	O
Multimedia	B-Device
PC	I-Device
standard	O
,	O
the	O
Sound	B-Application
Blaster	I-Application
cloned	O
the	O
AdLib	O
and	O
added	O
a	O
sound	O
coprocessor	O
for	O
recording	O
and	O
playback	O
of	O
digital	O
audio	O
.	O
</s>
<s>
The	O
card	O
also	O
included	O
a	O
game	B-Protocol
port	I-Protocol
for	O
adding	O
a	O
joystick	B-Device
,	O
and	O
the	O
capability	O
to	O
interface	O
to	O
MIDI	O
equipment	O
using	O
the	O
game	B-Protocol
port	I-Protocol
and	O
a	O
special	O
cable	O
.	O
</s>
<s>
With	O
AdLib	O
compatibility	B-Device
and	O
more	O
features	O
at	O
nearly	O
the	O
same	O
price	O
,	O
most	O
buyers	O
chose	O
the	O
Sound	B-Application
Blaster	I-Application
.	O
</s>
<s>
Roland	O
also	O
made	O
sound	B-Device
cards	I-Device
in	O
the	O
late	O
1980s	O
such	O
as	O
the	O
MT-32	O
and	O
LAPC-I	O
.	O
</s>
<s>
Many	O
games	O
had	O
music	O
written	O
for	O
their	O
cards	O
,	O
such	O
as	O
Silpheed	B-Device
and	O
Police	O
Quest	O
II	O
.	O
</s>
<s>
The	O
cards	O
were	O
often	O
poor	O
at	O
sound	O
effects	O
such	O
as	O
laughs	O
,	O
but	O
for	O
music	O
was	O
by	O
far	O
the	O
best	O
sound	B-Device
cards	I-Device
available	O
until	O
the	O
mid-nineties	O
.	O
</s>
<s>
By	O
1992	O
,	O
one	O
sound	B-Device
card	I-Device
vendor	O
advertised	O
that	O
its	O
product	O
was	O
"	O
Sound	B-Application
Blaster	I-Application
,	O
AdLib	O
,	O
Disney	O
Sound	O
Source	O
and	O
Covox	O
Speech	O
Thing	O
Compatible	B-Device
!	O
"	O
</s>
<s>
Responding	O
to	O
readers	O
complaining	O
about	O
an	O
article	O
on	O
sound	B-Device
cards	I-Device
that	O
unfavorably	O
mentioned	O
the	O
Gravis	B-Application
Ultrasound	I-Application
,	O
Computer	O
Gaming	O
World	O
stated	O
in	O
January	O
1994	O
that	O
,	O
"	O
The	O
de	O
facto	O
standard	O
in	O
the	O
gaming	O
world	O
is	O
Sound	B-Application
Blaster	I-Application
compatibility	B-Device
...	O
</s>
<s>
The	O
magazine	O
that	O
year	O
stated	O
that	O
Wing	B-Device
Commander	I-Device
II	I-Device
was	O
"	O
Probably	O
the	O
game	O
responsible	O
"	O
for	O
making	O
it	O
the	O
standard	O
card	O
.	O
</s>
<s>
The	O
Sound	B-Application
Blaster	I-Application
line	O
of	O
cards	O
,	O
together	O
with	O
the	O
first	O
inexpensive	O
CD-ROM	B-Device
drives	O
and	O
evolving	O
video	O
technology	O
,	O
ushered	O
in	O
a	O
new	O
era	O
of	O
multimedia	O
computer	O
applications	O
that	O
could	O
play	O
back	O
CD	O
audio	O
,	O
add	O
recorded	O
dialogue	O
to	O
video	O
games	O
,	O
or	O
even	O
reproduce	O
full	B-Application
motion	I-Application
video	I-Application
(	O
albeit	O
at	O
much	O
lower	O
resolutions	O
and	O
quality	O
in	O
early	O
days	O
)	O
.	O
</s>
<s>
The	O
widespread	O
decision	O
to	O
support	O
the	O
Sound	B-Application
Blaster	I-Application
design	O
in	O
multimedia	O
and	O
entertainment	O
titles	O
meant	O
that	O
future	O
sound	B-Device
cards	I-Device
such	O
as	O
Media	O
Vision	O
's	O
Pro	O
Audio	O
Spectrum	O
and	O
the	O
Gravis	B-Application
Ultrasound	I-Application
had	O
to	O
be	O
Sound	B-Application
Blaster	I-Application
compatible	B-Device
if	O
they	O
were	O
to	O
sell	O
well	O
.	O
</s>
<s>
Until	O
the	O
early	O
2000s	O
,	O
when	O
the	O
AC'97	O
audio	O
standard	O
became	O
more	O
widespread	O
and	O
eventually	O
usurped	O
the	O
SoundBlaster	B-Application
as	O
a	O
standard	O
due	O
to	O
its	O
low	O
cost	O
and	O
integration	O
into	O
many	O
motherboards	B-Device
,	O
Sound	B-Application
Blaster	I-Application
compatibility	B-Device
was	O
a	O
standard	O
that	O
many	O
other	O
sound	B-Device
cards	I-Device
supported	O
to	O
maintain	O
compatibility	B-Device
with	O
many	O
games	O
and	O
applications	O
released	O
.	O
</s>
<s>
When	O
game	O
company	O
Sierra	O
On-Line	O
opted	O
to	O
support	O
add-on	O
music	O
hardware	O
in	O
addition	O
to	O
built-in	O
hardware	O
such	O
as	O
the	O
PC	B-Device
speaker	I-Device
and	O
built-in	O
sound	O
capabilities	O
of	O
the	O
IBM	B-Device
PCjr	I-Device
and	O
Tandy	B-Device
1000	I-Device
,	O
what	O
could	O
be	O
done	O
with	O
sound	O
and	O
music	O
on	O
the	O
IBM	O
PC	O
changed	O
dramatically	O
.	O
</s>
<s>
Two	O
of	O
the	O
companies	O
Sierra	O
partnered	O
with	O
were	O
Roland	O
and	O
AdLib	O
,	O
opting	O
to	O
produce	O
in-game	O
music	O
for	O
King	B-Application
's	I-Application
Quest	I-Application
4	I-Application
that	O
supported	O
the	O
MT-32	O
and	O
AdLib	O
Music	O
Synthesizer	O
.	O
</s>
<s>
before	O
the	O
Sound	B-Application
Blaster	I-Application
brought	O
digital	O
audio	O
playback	O
to	O
the	O
PC	O
.	O
</s>
<s>
Early	O
ISA	B-Architecture
bus	I-Architecture
sound	B-Device
cards	I-Device
were	O
half-duplex	O
,	O
meaning	O
they	O
could	O
n't	O
record	O
and	O
play	O
digitized	O
sound	O
simultaneously	O
.	O
</s>
<s>
Later	O
,	O
ISA	B-Architecture
cards	I-Architecture
like	O
the	O
SoundBlaster	B-Application
AWE	O
series	O
and	O
Plug-and-play	O
Soundblaster	B-Application
clones	O
supported	O
simultaneous	O
recording	O
and	O
playback	O
,	O
but	O
at	O
the	O
expense	O
of	O
using	O
up	O
two	O
IRQ	O
and	O
DMA	O
channels	O
instead	O
of	O
one	O
.	O
</s>
<s>
Conventional	B-Protocol
PCI	I-Protocol
bus	B-General_Concept
cards	O
generally	O
do	O
not	O
have	O
these	O
limitations	O
and	O
are	O
mostly	O
full-duplex	O
.	O
</s>
<s>
Sound	B-Device
cards	I-Device
have	O
evolved	O
in	O
terms	O
of	O
digital	O
audio	O
sampling	O
rate	O
(	O
starting	O
from	O
8-bit	O
,	O
to	O
32-bit	O
,	O
that	O
the	O
latest	O
solutions	O
support	O
)	O
.	O
</s>
<s>
With	O
some	O
exceptions	O
,	O
for	O
years	O
,	O
sound	B-Device
cards	I-Device
,	O
most	O
notably	O
the	O
Sound	B-Application
Blaster	I-Application
series	O
and	O
their	O
compatibles	O
,	O
had	O
only	O
one	O
or	O
two	O
channels	O
of	O
digital	O
sound	O
.	O
</s>
<s>
The	O
first	O
sound	B-Device
card	I-Device
solutions	O
were	O
mono	O
.	O
</s>
<s>
The	O
latest	O
sound	B-Device
cards	I-Device
support	O
up	O
to	O
8	O
audio	O
channels	O
for	O
the	O
7.1	O
speaker	O
setup	O
.	O
</s>
<s>
A	O
few	O
early	O
sound	B-Device
cards	I-Device
had	O
sufficient	O
power	O
to	O
drive	O
unpowered	O
speakers	O
directlyfor	O
example	O
,	O
two	O
watts	O
per	O
channel	O
.	O
</s>
<s>
With	O
the	O
popularity	O
of	O
amplified	O
speakers	O
,	O
sound	B-Device
cards	I-Device
no	O
longer	O
have	O
a	O
power	O
stage	O
,	O
though	O
in	O
many	O
cases	O
they	O
can	O
adequately	O
drive	O
headphones	O
.	O
</s>
<s>
Professional	O
sound	B-Device
cards	I-Device
are	O
sound	B-Device
cards	I-Device
optimized	O
for	O
high-fidelity	O
,	O
low-latency	O
multichannel	O
sound	O
recording	O
and	O
playback	O
.	O
</s>
<s>
Their	O
drivers	O
usually	O
follow	O
the	O
Audio	B-Library
Stream	I-Library
Input/Output	I-Library
protocol	O
for	O
use	O
with	O
professional	O
sound	O
engineering	O
and	O
music	O
software	O
.	O
</s>
<s>
Professional	O
sound	B-Device
cards	I-Device
are	O
usually	O
described	O
as	O
audio	O
interfaces	O
,	O
and	O
sometimes	O
have	O
the	O
form	O
of	O
external	O
rack-mountable	B-Application
units	O
using	O
USB	B-Protocol
,	O
FireWire	B-Protocol
,	O
or	O
an	O
optical	O
interface	O
,	O
to	O
offer	O
sufficient	O
data	O
rates	O
.	O
</s>
<s>
The	O
emphasis	O
in	O
these	O
products	O
is	O
,	O
in	O
general	O
,	O
on	O
multiple	O
input	B-General_Concept
and	I-General_Concept
output	I-General_Concept
connectors	O
,	O
direct	O
hardware	O
support	O
for	O
multiple	O
input	B-General_Concept
and	I-General_Concept
output	I-General_Concept
sound	O
channels	O
,	O
as	O
well	O
as	O
higher	O
sampling	O
rates	O
and	O
fidelity	O
as	O
compared	O
to	O
the	O
usual	O
consumer	O
sound	B-Device
card	I-Device
.	O
</s>
<s>
On	O
the	O
other	O
hand	O
,	O
certain	O
features	O
of	O
consumer	O
sound	B-Device
cards	I-Device
such	O
as	O
support	O
for	O
3D	B-Application
audio	I-Application
,	O
hardware	O
acceleration	O
in	O
video	O
games	O
,	O
or	O
real-time	O
ambiance	O
effects	O
are	O
secondary	O
,	O
nonexistent	O
or	O
even	O
undesirable	O
in	O
professional	O
audio	O
interfaces	O
,	O
and	O
as	O
such	O
audio	O
interfaces	O
are	O
not	O
recommended	O
for	O
the	O
typical	O
home	O
user	O
.	O
</s>
<s>
The	O
typical	O
consumer-grade	O
sound	B-Device
card	I-Device
is	O
intended	O
for	O
generic	O
home	O
,	O
office	O
,	O
and	O
entertainment	O
purposes	O
with	O
an	O
emphasis	O
on	O
playback	O
and	O
casual	O
use	O
,	O
rather	O
than	O
catering	O
to	O
the	O
needs	O
of	O
audio	O
professionals	O
.	O
</s>
<s>
In	O
general	O
,	O
consumer-grade	O
sound	B-Device
cards	I-Device
impose	O
several	O
restrictions	O
and	O
inconveniences	O
that	O
would	O
be	O
unacceptable	O
to	O
an	O
audio	O
professional	O
.	O
</s>
<s>
Consumer	O
sound	B-Device
cards	I-Device
are	O
also	O
limited	O
in	O
the	O
effective	O
sampling	O
rates	O
and	O
bit	O
depths	O
they	O
can	O
actually	O
manage	O
and	O
have	O
lower	O
numbers	O
of	O
less	O
flexible	O
input	O
channels	O
.	O
</s>
<s>
Professional	O
studio	O
recording	O
use	O
typically	O
requires	O
more	O
than	O
the	O
two	O
channels	O
that	O
consumer	O
sound	B-Device
cards	I-Device
provide	O
,	O
and	O
more	O
accessible	O
connectors	O
,	O
unlike	O
the	O
variable	O
mixture	O
of	O
internal	O
—	O
and	O
sometimes	O
virtual	O
—	O
and	O
external	O
connectors	O
found	O
in	O
consumer-grade	O
sound	B-Device
cards	I-Device
.	O
</s>
<s>
In	O
1984	O
,	O
the	O
first	O
IBM	B-Device
PCjr	I-Device
had	O
a	O
rudimentary	O
3-voice	O
sound	O
synthesis	O
chip	O
(	O
the	O
SN76489	B-Device
)	O
which	O
was	O
capable	O
of	O
generating	O
three	O
square-wave	O
tones	O
with	O
variable	O
amplitude	B-Application
,	O
and	O
a	O
pseudo-white	O
noise	O
channel	O
that	O
could	O
generate	O
primitive	O
percussion	O
sounds	O
.	O
</s>
<s>
The	O
Tandy	B-Device
1000	I-Device
,	O
initially	O
a	O
clone	O
of	O
the	O
PCjr	B-Device
,	O
duplicated	O
this	O
functionality	O
,	O
with	O
the	O
Tandy	B-Device
1000	I-Device
TL/SL/RL	O
models	O
adding	O
digital	O
sound	O
recording	O
and	O
playback	O
capabilities	O
.	O
</s>
<s>
Many	O
games	O
during	O
the	O
1980s	O
that	O
supported	O
the	O
PCjr	B-Device
's	O
video	O
standard	O
(	O
described	O
as	O
Tandy-compatible	O
,	O
Tandy	O
graphics	O
,	O
or	O
TGA	O
)	O
also	O
supported	O
PCjr/Tandy	O
1000	O
audio	O
.	O
</s>
<s>
In	O
the	O
late	O
1990s	O
,	O
many	O
computer	O
manufacturers	O
began	O
to	O
replace	O
plug-in	O
sound	B-Device
cards	I-Device
with	O
an	O
audio	B-Algorithm
codec	I-Algorithm
chip	O
(	O
a	O
combined	O
audio	O
AD/DA	O
-converter	O
)	O
integrated	O
into	O
the	O
motherboard	B-Device
.	O
</s>
<s>
Others	O
used	O
inexpensive	O
ACR	O
slot	O
accessory	B-Device
cards	I-Device
.	O
</s>
<s>
From	O
around	O
2001	O
,	O
many	O
motherboards	B-Device
incorporated	O
full-featured	O
sound	B-Device
cards	I-Device
,	O
usually	O
in	O
the	O
form	O
of	O
a	O
custom	O
chipset	O
,	O
providing	O
something	O
akin	O
to	O
full	O
Sound	B-Application
Blaster	I-Application
compatibility	B-Device
and	O
relatively	O
high-quality	O
sound	O
.	O
</s>
<s>
However	O
,	O
these	O
features	O
were	O
dropped	O
when	O
AC'97	O
was	O
superseded	O
by	O
Intel	O
's	O
HD	O
Audio	O
standard	O
,	O
which	O
was	O
released	O
in	O
2004	O
,	O
again	O
specified	O
the	O
use	O
of	O
a	O
codec	B-General_Concept
chip	O
,	O
and	O
slowly	O
gained	O
acceptance	O
.	O
</s>
<s>
As	O
of	O
2011	O
,	O
most	O
motherboards	B-Device
have	O
returned	O
to	O
using	O
a	O
codec	B-General_Concept
chip	O
,	O
albeit	O
an	O
HD	O
Audio	O
compatible	B-Device
one	O
,	O
and	O
the	O
requirement	O
for	O
Sound	B-Application
Blaster	I-Application
compatibility	B-Device
relegated	O
to	O
history	O
.	O
</s>
<s>
Various	O
non-IBM	O
PC	O
compatible	B-Device
computers	O
,	O
such	O
as	O
early	O
home	O
computers	O
like	O
the	O
Commodore	O
64	O
(	O
1982	O
)	O
(	O
and	O
by	O
extension	O
Commodore	B-Device
128	I-Device
in	O
1985	O
)	O
and	O
Amiga	B-Device
(	O
1985	O
)	O
,	O
NEC	O
's	O
PC-88	B-Device
,	O
and	O
PC-98	B-Operating_System
,	O
Fujitsu	O
's	O
FM-7	B-Device
and	O
FM	B-Device
Towns	I-Device
,	O
Sharp	O
's	O
X1	B-Device
and	O
X68000	B-Device
,	O
Acorn	O
's	O
BBC	B-Device
Micro	I-Device
,	O
Electron	B-Device
and	O
Archimedes	B-Device
,	O
Atari	O
's	O
8-bit	B-Device
home	I-Device
computers	I-Device
,	O
ST	B-Device
and	O
Falcon	B-Device
,	O
Amstrad	O
's	O
CPC	B-Device
,	O
later	O
revisions	O
of	O
Sinclair	O
's	O
ZX	B-Operating_System
Spectrum	I-Operating_System
,	O
the	O
MSX	B-Operating_System
,	O
Apple	B-Device
's	I-Device
Macintosh	I-Device
and	O
IIGS	B-Device
,	O
and	O
workstations	B-Device
from	O
manufacturers	O
like	O
Sun	O
,	O
Silicon	O
Graphics	O
and	O
NeXT	O
have	O
had	O
their	O
own	O
motherboard-integrated	O
sound	O
devices	O
.	O
</s>
<s>
In	O
some	O
cases	O
,	O
most	O
notably	O
in	O
those	O
of	O
the	O
Macintosh	B-Device
,	O
IIGS	B-Device
,	O
Amiga	B-Device
,	O
C64	O
,	O
PC-98	B-Operating_System
,	O
SGI	O
Indigo	O
,	O
X68000	B-Device
,	O
MSX	B-Operating_System
,	O
Falcon	B-Device
,	O
Archimedes	B-Device
,	O
FM-7	B-Device
and	O
FM	B-Device
Towns	I-Device
,	O
they	O
provide	O
very	O
advanced	O
capabilities	O
(	O
as	O
of	O
the	O
time	O
of	O
manufacture	O
)	O
,	O
in	O
others	O
they	O
are	O
only	O
minimal	O
capabilities	O
.	O
</s>
<s>
Some	O
of	O
these	O
platforms	O
have	O
also	O
had	O
sound	B-Device
cards	I-Device
designed	O
for	O
their	O
bus	B-General_Concept
architectures	O
that	O
cannot	O
be	O
used	O
in	O
a	O
standard	O
PC	O
.	O
</s>
<s>
Several	O
Japanese	O
computer	O
platforms	O
,	O
including	O
the	O
PC-88	B-Device
,	O
PC-98	B-Operating_System
,	O
MSX	B-Operating_System
,	O
X1	B-Device
,	O
X68000	B-Device
,	O
FM	B-Device
Towns	I-Device
and	O
FM-7	B-Device
,	O
featured	O
built-in	O
FM	O
synthesis	O
sound	O
from	O
Yamaha	O
by	O
the	O
mid-1980s	O
.	O
</s>
<s>
By	O
1989	O
,	O
the	O
FM	B-Device
Towns	I-Device
computer	O
platform	O
featured	O
built-in	O
PCM	B-Algorithm
sample-based	O
sound	O
and	O
supported	O
the	O
CD-ROM	B-Device
format	O
.	O
</s>
<s>
The	O
custom	O
sound	O
chip	O
on	O
Amiga	B-Device
,	O
named	O
Paula	O
,	O
had	O
four	O
digital	O
sound	O
channels	O
(	O
2	O
for	O
the	O
left	O
speaker	O
and	O
2	O
for	O
the	O
right	O
)	O
with	O
8-bit	O
resolution	O
for	O
each	O
channel	O
and	O
a	O
6-bit	O
volume	O
control	O
per	O
channel	O
.	O
</s>
<s>
Sound	O
playback	O
on	O
Amiga	B-Device
was	O
done	O
by	O
reading	O
directly	O
from	O
the	O
chip	O
RAM	O
without	O
using	O
the	O
main	O
CPU	O
.	O
</s>
<s>
The	O
earliest	O
known	O
sound	B-Device
card	I-Device
used	O
by	O
computers	O
was	O
the	O
Gooch	O
Synthetic	O
Woodwind	O
,	O
a	O
music	O
device	O
for	O
PLATO	B-Operating_System
terminals	I-Operating_System
,	O
and	O
is	O
widely	O
hailed	O
as	O
the	O
precursor	O
to	O
sound	B-Device
cards	I-Device
and	O
MIDI	O
.	O
</s>
<s>
Certain	O
early	O
arcade	O
machines	O
made	O
use	O
of	O
sound	B-Device
cards	I-Device
to	O
achieve	O
playback	O
of	O
complex	O
audio	O
waveforms	O
and	O
digital	O
music	O
,	O
despite	O
being	O
already	O
equipped	O
with	O
onboard	O
audio	O
.	O
</s>
<s>
An	O
example	O
of	O
a	O
sound	B-Device
card	I-Device
used	O
in	O
arcade	O
machines	O
is	O
the	O
Digital	O
Compression	O
System	O
card	O
,	O
used	O
in	O
games	O
from	O
Midway	O
.	O
</s>
<s>
For	O
example	O
,	O
Mortal	B-Application
Kombat	I-Application
II	I-Application
on	O
the	O
Midway	O
T-Unit	O
hardware	O
.	O
</s>
<s>
The	O
card	O
is	O
also	O
used	O
in	O
the	O
arcade	O
version	O
of	O
Midway	O
and	O
Aerosmith	O
's	O
Revolution	B-Application
X	I-Application
for	O
complex	O
looping	O
music	O
and	O
speech	O
playback	O
.	O
</s>
<s>
MSX	B-Operating_System
computers	O
,	O
while	O
equipped	O
with	O
built-in	O
sound	O
capabilities	O
,	O
also	O
relied	O
on	O
sound	B-Device
cards	I-Device
to	O
produce	O
better	O
quality	O
audio	O
.	O
</s>
<s>
Prior	O
to	O
the	O
Moonsound	O
,	O
there	O
were	O
also	O
sound	B-Device
cards	I-Device
called	O
MSX	B-Operating_System
Music	O
and	O
MSX	B-Operating_System
Audio	O
for	O
the	O
system	O
,	O
which	O
uses	O
OPL2	O
and	O
OPL3	O
chipsets	O
.	O
</s>
<s>
The	O
Apple	B-Device
II	I-Device
computers	O
,	O
which	O
did	O
not	O
have	O
sound	O
capabilities	O
beyond	O
rapidly	O
clicking	O
a	O
speaker	O
until	O
the	O
IIGS	B-Device
,	O
could	O
use	O
plug-in	O
sound	B-Device
cards	I-Device
from	O
a	O
variety	O
of	O
manufacturers	O
.	O
</s>
<s>
A	O
12-voice	O
,	O
single-card	O
clone	O
of	O
the	O
Mockingboard	O
called	O
the	O
Phasor	B-Application
was	O
made	O
by	O
Applied	O
Engineering	O
.	O
</s>
<s>
The	O
ZX	B-Operating_System
Spectrum	I-Operating_System
that	O
initially	O
only	O
had	O
a	O
beeper	O
had	O
some	O
sound	B-Device
cards	I-Device
made	O
for	O
it	O
.	O
</s>
<s>
The	O
Commodore	O
64	O
,	O
while	O
having	O
an	O
integrated	O
SID	O
chip	O
,	O
also	O
had	O
sound	B-Device
cards	I-Device
made	O
for	O
it	O
.	O
</s>
<s>
The	O
PC-98	B-Operating_System
series	O
of	O
computers	O
,	O
like	O
their	O
IBM	O
PC	O
cousins	O
,	O
also	O
do	O
not	O
have	O
integrated	O
sound	O
contrary	O
to	O
popular	O
belief	O
,	O
and	O
their	O
default	O
configuration	O
is	O
a	O
PC	B-Device
speaker	I-Device
driven	O
by	O
a	O
timer	O
.	O
</s>
<s>
Sound	B-Device
cards	I-Device
were	O
made	O
for	O
the	O
C-Bus	O
expansion	B-Device
slots	I-Device
that	O
these	O
computers	O
had	O
,	O
most	O
of	O
which	O
used	O
Yamaha	O
's	O
FM	O
and	O
PSG	O
chips	O
and	O
made	O
by	O
NEC	O
themselves	O
,	O
although	O
aftermarket	O
clones	O
can	O
also	O
be	O
purchased	O
,	O
and	O
Creative	O
did	O
release	O
a	O
C-Bus	O
version	O
of	O
the	O
SoundBlaster	B-Application
line	O
of	O
sound	B-Device
cards	I-Device
for	O
the	O
platform	O
.	O
</s>
<s>
Devices	O
such	O
as	O
the	O
Covox	O
Speech	O
Thing	O
could	O
be	O
attached	O
to	O
the	O
parallel	O
port	O
of	O
an	O
IBM	O
PC	O
and	O
fed	O
6	O
-	O
or	O
8-bit	O
PCM	B-Algorithm
sample	O
data	O
to	O
produce	O
audio	O
.	O
</s>
<s>
Also	O
,	O
many	O
types	O
of	O
professional	O
sound	B-Device
cards	I-Device
take	O
the	O
form	O
of	O
an	O
external	O
FireWire	B-Protocol
or	O
USB	B-Protocol
unit	O
,	O
usually	O
for	O
convenience	O
and	O
improved	O
fidelity	O
.	O
</s>
<s>
Sound	B-Device
cards	I-Device
using	O
the	O
PC	B-Architecture
Card	I-Architecture
interface	O
were	O
available	O
before	O
laptop	O
and	O
notebook	O
computers	O
routinely	O
had	O
onboard	O
sound	O
.	O
</s>
<s>
USB	B-Protocol
sound	B-Device
cards	I-Device
are	O
external	O
devices	O
that	O
plug	O
into	O
the	O
computer	O
via	O
USB	B-Protocol
.	O
</s>
<s>
DJs	O
who	O
use	O
DJ	O
software	O
typically	O
use	O
sound	B-Device
cards	I-Device
integrated	O
into	O
DJ	O
controllers	O
or	O
specialized	O
DJ	O
sound	B-Device
cards	I-Device
.	O
</s>
<s>
DJ	O
sound	B-Device
cards	I-Device
sometimes	O
have	O
inputs	O
with	O
phono	O
preamplifiers	O
to	O
allow	O
turntables	O
to	O
be	O
connected	O
to	O
the	O
computer	O
to	O
control	O
the	O
software	O
's	O
playback	O
of	O
music	O
files	O
with	O
vinyl	O
emulation	O
.	O
</s>
<s>
The	O
USB	B-Protocol
specification	O
defines	O
a	O
standard	O
interface	O
,	O
the	O
USB	B-Protocol
audio	O
device	O
class	O
,	O
allowing	O
a	O
single	O
driver	O
to	O
work	O
with	O
the	O
various	O
USB	B-Protocol
sound	O
devices	O
and	O
interfaces	O
on	O
the	O
market	O
.	O
</s>
<s>
Mac	B-Device
OS	O
X	O
,	O
Windows	O
,	O
and	O
Linux	B-Operating_System
support	O
this	O
standard	O
.	O
</s>
<s>
However	O
,	O
some	O
USB	B-Protocol
sound	B-Device
cards	I-Device
do	O
not	O
conform	O
to	O
the	O
standard	O
and	O
require	O
proprietary	O
drivers	O
from	O
the	O
manufacturer	O
.	O
</s>
<s>
Cards	O
meeting	O
the	O
older	O
USB	B-Protocol
1.1	O
specification	O
are	O
capable	O
of	O
high-quality	O
sound	O
with	O
a	O
limited	O
number	O
of	O
channels	O
,	O
but	O
USB	B-Protocol
2.0	O
or	O
later	O
is	O
more	O
capable	O
.	O
</s>
<s>
The	O
main	O
function	O
of	O
a	O
sound	B-Device
card	I-Device
is	O
to	O
play	O
audio	O
,	O
usually	O
music	O
,	O
with	O
varying	O
formats	O
(	O
monophonic	O
,	O
stereophonic	O
,	O
various	O
multiple	O
speaker	O
setups	O
)	O
and	O
degrees	O
of	O
control	O
.	O
</s>
<s>
The	O
source	O
may	O
be	O
a	O
CD	O
or	O
DVD	O
,	O
a	O
file	O
,	O
streamed	O
audio	O
,	O
or	O
any	O
external	O
source	O
connected	O
to	O
a	O
sound	B-Device
card	I-Device
input	O
.	O
</s>
<s>
Sometimes	O
sound	B-Device
card	I-Device
hardware	O
and	O
drivers	O
do	O
not	O
support	O
recording	O
a	O
source	O
that	O
is	O
being	O
played	O
.	O
</s>
<s>
Free	O
and	O
commercial	O
software	O
is	O
available	O
for	O
this	O
purpose	O
;	O
there	O
are	O
also	O
online	O
services	O
that	O
generate	O
audio	O
files	O
for	O
any	O
desired	O
waveforms	O
,	O
playable	O
through	O
a	O
sound	B-Device
card	I-Device
.	O
</s>
<s>
For	O
example	O
,	O
a	O
very-low-distortion	O
sinewave	O
oscillator	O
can	O
be	O
used	O
as	O
input	O
to	O
equipment	O
under	O
test	O
;	O
the	O
output	O
is	O
sent	O
to	O
a	O
sound	B-Device
card	I-Device
's	O
line	O
input	O
and	O
run	O
through	O
Fourier	B-Algorithm
transform	I-Algorithm
software	O
to	O
find	O
the	O
amplitude	B-Application
of	O
each	O
harmonic	O
of	O
the	O
added	O
distortion	O
.	O
</s>
<s>
There	O
are	O
programs	O
that	O
allow	O
a	O
sound	B-Device
card	I-Device
to	O
be	O
used	O
as	O
an	O
audio-frequency	O
oscilloscope	O
.	O
</s>
<s>
For	O
all	O
measurement	O
purposes	O
a	O
sound	B-Device
card	I-Device
must	O
be	O
chosen	O
with	O
good	O
audio	O
properties	O
.	O
</s>
<s>
A	O
typical	O
integrated	O
sound	B-Device
card	I-Device
,	O
the	O
Realtek	O
ALC887	O
,	O
according	O
to	O
its	O
data	O
sheet	O
has	O
distortion	O
of	O
about	O
80dB	O
below	O
the	O
fundamental	O
;	O
cards	O
are	O
available	O
with	O
distortion	O
better	O
than	O
−100dB	O
.	O
</s>
<s>
Sound	B-Device
cards	I-Device
with	O
a	O
sampling	O
rate	O
of	O
192kHz	O
can	O
be	O
used	O
to	O
synchronize	O
the	O
clock	O
of	O
the	O
computer	O
with	O
a	O
time	O
signal	O
transmitter	O
working	O
on	O
frequencies	O
below	O
96kHz	O
like	O
DCF	O
77	O
with	O
a	O
special	O
software	O
and	O
a	O
coil	O
at	O
the	O
entrance	O
of	O
the	O
sound	B-Device
card	I-Device
,	O
working	O
as	O
antenna	O
.	O
</s>
<s>
To	O
use	O
a	O
sound	B-Device
card	I-Device
,	O
the	O
operating	B-General_Concept
system	I-General_Concept
(	O
OS	O
)	O
typically	O
requires	O
a	O
specific	O
device	B-Application
driver	I-Application
,	O
a	O
low-level	O
program	O
that	O
handles	O
the	O
data	O
connections	O
between	O
the	O
physical	O
hardware	O
and	O
the	O
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
Some	O
operating	B-General_Concept
systems	I-General_Concept
include	O
the	O
drivers	O
for	O
many	O
cards	O
;	O
for	O
cards	O
not	O
so	O
supported	O
,	O
drivers	O
are	O
supplied	O
with	O
the	O
card	O
,	O
or	O
available	O
for	O
download	O
.	O
</s>
<s>
DOS	B-Device
programs	O
for	O
the	O
IBM	O
PC	O
often	O
had	O
to	O
use	O
universal	O
middleware	B-General_Concept
driver	O
libraries	O
(	O
such	O
as	O
the	O
HMI	O
Sound	O
Operating	B-General_Concept
System	I-General_Concept
,	O
the	O
Miles	O
Audio	B-Library
Interface	I-Library
Libraries	I-Library
(	O
AIL	O
)	O
,	O
the	O
Miles	B-Library
Sound	I-Library
System	I-Library
etc	O
.	O
)	O
</s>
<s>
which	O
had	O
drivers	O
for	O
most	O
common	O
sound	B-Device
cards	I-Device
,	O
since	O
DOS	B-Device
itself	O
had	O
no	O
real	O
concept	O
of	O
a	O
sound	B-Device
card	I-Device
.	O
</s>
<s>
Often	O
the	O
driver	O
is	O
a	O
Sound	B-Application
Blaster	I-Application
and	O
AdLib	O
emulator	O
designed	O
to	O
allow	O
their	O
products	O
to	O
emulate	O
a	O
Sound	B-Application
Blaster	I-Application
and	O
AdLib	O
,	O
and	O
to	O
allow	O
games	O
that	O
could	O
only	O
use	O
SoundBlaster	B-Application
or	O
AdLib	O
sound	O
to	O
work	O
with	O
the	O
card	O
.	O
</s>
<s>
Finally	O
,	O
some	O
programs	O
simply	O
had	O
driver	O
or	O
middleware	B-General_Concept
source	O
code	O
incorporated	O
into	O
the	O
program	O
itself	O
for	O
the	O
sound	B-Device
cards	I-Device
that	O
were	O
supported	O
.	O
</s>
<s>
Microsoft	B-Application
Windows	I-Application
uses	O
drivers	O
generally	O
written	O
by	O
the	O
sound	B-Device
card	I-Device
manufacturers	O
.	O
</s>
<s>
USB	B-Protocol
audio	O
device	O
class	O
support	O
is	O
present	O
from	O
Windows	O
98	O
SE	O
onwards	O
.	O
</s>
<s>
Since	O
Microsoft	O
's	O
Universal	B-Device
Audio	I-Device
Architecture	I-Device
(	O
UAA	O
)	O
initiative	O
which	O
supports	O
HD	O
Audio	O
,	O
FireWire	B-Protocol
and	O
USB	B-Protocol
audio	O
device	O
class	O
standards	O
,	O
a	O
universal	O
class	O
driver	O
by	O
Microsoft	O
can	O
be	O
used	O
.	O
</s>
<s>
The	O
driver	O
is	O
included	O
with	O
Windows	B-Application
Vista	I-Application
.	O
</s>
<s>
For	O
Windows	B-Application
XP	I-Application
,	O
Windows	B-Application
2000	I-Application
or	O
Windows	B-Application
Server	I-Application
2003	I-Application
,	O
the	O
driver	O
can	O
be	O
obtained	O
by	O
contacting	O
Microsoft	O
support	O
.	O
</s>
<s>
A	O
number	O
of	O
versions	O
of	O
UNIX	B-Application
make	O
use	O
of	O
the	O
portable	O
Open	B-Library
Sound	I-Library
System	I-Library
(	O
OSS	O
)	O
.	O
</s>
<s>
Most	O
present	O
day	O
Linux	B-Application
distributions	I-Application
make	O
use	O
of	O
the	O
Advanced	B-Application
Linux	I-Application
Sound	I-Application
Architecture	I-Application
(	O
ALSA	B-Application
)	O
.	O
</s>
<s>
Up	O
until	O
Linux	B-Operating_System
kernel	I-Operating_System
2.4	I-Operating_System
,	O
OSS	O
was	O
the	O
standard	O
sound	O
architecture	O
for	O
Linux	B-Operating_System
,	O
although	O
ALSA	B-Application
can	O
be	O
downloaded	O
,	O
compiled	O
and	O
installed	O
separately	O
for	O
kernels	B-Operating_System
2.2	O
or	O
higher	O
.	O
</s>
<s>
But	O
from	O
kernel	B-Operating_System
2.5	O
onwards	O
,	O
ALSA	B-Application
was	O
integrated	O
into	O
the	O
kernel	B-Operating_System
and	O
the	O
OSS	O
native	O
drivers	O
were	O
deprecated	O
.	O
</s>
<s>
Backwards	O
compatibility	B-Device
with	O
OSS-based	O
software	O
is	O
maintained	O
,	O
however	O
,	O
by	O
the	O
use	O
of	O
the	O
ALSA-OSS	O
compatibility	B-Device
API	O
and	O
the	O
OSS-emulation	O
kernel	B-Operating_System
modules	O
.	O
</s>
<s>
Mockingboard	O
support	O
on	O
the	O
Apple	B-Device
II	I-Device
is	O
usually	O
incorporated	O
into	O
the	O
programs	O
itself	O
as	O
many	O
programs	O
for	O
the	O
Apple	B-Device
II	I-Device
boot	O
directly	O
from	O
disk	O
.	O
</s>
