<s>
In	O
the	O
x86	B-Operating_System
architecture	I-Operating_System
,	O
an	O
input/output	B-Device
base	I-Device
address	I-Device
is	O
the	O
first	O
I/O	B-Architecture
address	I-Architecture
of	O
a	O
range	O
of	O
consecutive	O
read/write	O
addresses	O
that	O
a	O
device	O
uses	O
on	O
the	O
x86	B-Operating_System
's	O
I/O	B-General_Concept
bus	I-General_Concept
.	O
</s>
<s>
This	O
base	B-General_Concept
address	I-General_Concept
is	O
sometimes	O
called	O
an	O
I/O	B-Architecture
port	I-Architecture
.	O
</s>
<s>
This	O
table	O
represents	O
the	O
common	O
I/O	B-Architecture
address	I-Architecture
ranges	O
for	O
device	O
assignments	O
in	O
IBM	O
PC	O
compatible	O
computers	O
.	O
</s>
<s>
The	O
base	B-General_Concept
address	I-General_Concept
is	O
the	O
first	O
in	O
each	O
range	O
.	O
</s>
<s>
Different	O
types	O
of	O
devices	O
can	O
vary	O
in	O
the	O
number	O
of	O
I/O	B-Architecture
ports	I-Architecture
they	O
need	O
for	O
communication	O
with	O
the	O
CPU	O
,	O
therefore	O
the	O
extent	O
of	O
the	O
address	O
range	O
varies	O
.	O
</s>
<s>
Also	O
,	O
address	O
decoders	O
often	O
do	O
not	O
decode	O
all	O
address	O
bits	O
,	O
causing	O
the	O
necessary	O
I/O	B-Architecture
address	I-Architecture
range	O
window	O
to	O
be	O
larger	O
than	O
necessary	O
or	O
mirrored	O
to	O
other	O
addresses	O
as	O
well	O
.	O
</s>
<s>
Depending	O
on	O
the	O
adapter	O
's	O
configuration	O
,	O
this	O
may	O
be	O
mapped	O
in	O
at	O
different	O
locations	O
within	O
the	O
PC	O
's	O
I/O	B-Architecture
address	I-Architecture
range	O
.	O
</s>
<s>
Assuming	O
,	O
the	O
adapter	O
would	O
present	O
a	O
third	O
parallel	B-Device
port	I-Device
(	O
with	O
base	B-General_Concept
address	I-General_Concept
0x0278	O
)	O
,	O
this	O
would	O
result	O
in	O
the	O
status	O
port	O
mapped	O
in	O
at	O
0x0279	O
in	O
the	O
CPU	O
'S	O
I/O	B-Architecture
address	I-Architecture
space	O
.	O
</s>
<s>
When	O
there	O
are	O
two	O
or	O
more	O
identical	O
devices	O
in	O
a	O
computer	O
system	O
,	O
each	O
device	O
would	O
be	O
mapped	O
to	O
a	O
different	O
base	B-General_Concept
address	I-General_Concept
(	O
e.g.	O
</s>
<s>
I/O	B-Architecture
address	I-Architecture
range	O
Device	O
00	O
–	O
1F	O
First	O
DMA	B-General_Concept
controller	I-General_Concept
8237	O
A-5	O
20	O
–	O
3F	O
First	O
Programmable	B-Architecture
interrupt	I-Architecture
controller	I-Architecture
,	O
8259A	B-Device
,	O
40	O
–	O
5F	O
Programmable	B-Device
interval	I-Device
timer	I-Device
(	O
System	B-Device
Timer	I-Device
)	O
,	O
8254	B-Device
60	O
–	O
6F	O
Keyboard	B-Device
,	O
8042	B-Device
70	O
–	O
7F	O
Real-time	O
clock	O
,	O
NMI	O
mask	O
80	O
–	O
9F	O
DMA	B-General_Concept
Page	O
Register	O
,	O
74LS612	O
87	O
DMA	B-General_Concept
Channel	O
0	O
83	O
DMA	B-General_Concept
Channel	O
1	O
81	O
DMA	B-General_Concept
Channel	O
2	O
82	O
DMA	B-General_Concept
Channel	O
3	O
8B	O
DMA	B-General_Concept
Channel	O
5	O
89	O
DMA	B-General_Concept
Channel	O
6	O
8A	O
DMA	B-General_Concept
Channel	O
7	O
8F	O
Refresh	O
A0	O
–	O
BF	O
Second	O
Programmable	B-Architecture
interrupt	I-Architecture
controller	I-Architecture
,	O
8259A	B-Device
,	O
Slave	O
C0	O
–	O
DF	O
Second	O
DMA	B-General_Concept
controller	I-General_Concept
8237	O
A-5	O
F0	O
Clear	O
80287	O
Busy	O
F1	O
Reset	O
80287	O
F8	O
–	O
FF	O
Math	B-General_Concept
coprocessor	I-General_Concept
,	O
80287	O
F0	O
–	O
F5	O
PCjr	B-Device
Disk	O
Controller	O
F8	O
–	O
FF	O
Reserved	O
for	O
future	O
microprocessor	O
extensions	O
100	O
–	O
10F	O
POS	O
Programmable	O
Option	O
Select	O
(	O
PS/2	O
)	O
110	O
–	O
1EF	O
System	O
I/O	O
channel	O
140	O
–	O
15F	O
Secondary	O
SCSI	O
host	O
adapter	O
170	O
–	O
177	O
Secondary	O
Parallel	B-Protocol
ATA	I-Protocol
Disk	O
Controller	O
1F0	O
–	O
1F7	O
Primary	O
Parallel	B-Protocol
ATA	I-Protocol
Hard	B-Device
Disk	I-Device
Controller	O
200	O
–	O
20F	O
Game	B-Protocol
port	I-Protocol
210	O
–	O
217	O
Expansion	O
Unit	O
220	O
–	O
233	O
Sound	B-Application
Blaster	I-Application
and	O
most	O
other	O
sound	B-Device
cards	I-Device
278	O
–	O
27F	O
Parallel	B-Device
port	I-Device
3	O
280	O
–	O
29F	O
LCD	B-Device
on	O
Wyse	O
2108	O
PC	O
SMC	O
Elite	O
default	O
factory	O
setting	O
2B0	O
–	O
2DF	O
Alternate	O
Enhanced	B-Device
Graphics	I-Device
Adapter	I-Device
(	O
EGA	B-Device
)	O
display	O
control	O
2E8	O
–	O
2EF	O
Serial	B-Architecture
port	I-Architecture
4	O
2E1	O
GPIB/IEEE	O
-488	O
Adapter	O
0	O
2E2	O
–	O
2E3	O
Data	O
acquisition	O
2F8	O
–	O
2FF	O
Serial	B-Architecture
port	I-Architecture
2	O
300	O
–	O
31F	O
Prototype	O
Card	O
300	O
–	O
31F	O
Novell	O
NE1000	O
compatible	O
Ethernet	O
network	O
interfaces	O
300	O
–	O
31F	O
AMD	O
Am7990	O
Ethernet	O
network	O
interface	O
,	O
IRQ	B-General_Concept
=	O
5	O
.	O
</s>
<s>
320	O
–	O
323	O
ST-506	B-Device
and	O
compatible	O
hard	B-Device
disk	I-Device
drive	I-Device
interface	O
330	O
–	O
331	O
MPU-401	O
MIDI	O
processing	O
unit	O
on	O
most	O
sound	B-Device
cards	I-Device
340	O
–	O
35F	O
Primary	O
SCSI	O
host	O
adapter	O
370	O
–	O
377	O
Secondary	O
floppy	B-Device
disk	I-Device
drive	I-Device
controller	O
378	O
–	O
37F	O
Parallel	B-Device
port	I-Device
2	O
380	O
–	O
38C	O
Secondary	O
Binary	O
Synchronous	B-Protocol
Data	I-Protocol
Link	I-Protocol
Control	I-Protocol
(	O
SDLC	B-Protocol
)	O
adapter	O
388	O
–	O
389	O
AdLib	O
Music	O
Synthesizer	O
Card	O
3A0	O
–	O
3A9	O
Primary	O
Binary	O
Synchronous	B-Protocol
Data	I-Protocol
Link	I-Protocol
Control	I-Protocol
(	O
SDLC	B-Protocol
)	O
adapter	O
3B0	O
–	O
3BB	O
Monochrome	B-Device
Display	I-Device
Adapter	I-Device
(	O
MDA	B-Device
)	O
display	O
control	O
3BC	O
–	O
3BF	O
Parallel	B-Device
port	I-Device
1	O
on	O
MDA	B-Device
card	I-Device
3C0	O
–	O
3CF	O
Enhanced	B-Device
Graphics	I-Device
Adapter	I-Device
(	O
EGA	B-Device
)	O
display	O
control	O
3D0	O
–	O
3DF	O
Color	B-Device
Graphics	I-Device
Adapter	I-Device
(	O
CGA	B-Device
)	O
3E8	O
–	O
3EF	O
Serial	B-Architecture
port	I-Architecture
3	O
3F0	O
–	O
3F7	O
Primary	O
floppy	B-Device
disk	I-Device
drive	I-Device
controller	O
.	O
</s>
<s>
Note	O
:	O
For	O
many	O
devices	O
listed	O
above	O
the	O
assignments	O
can	O
be	O
changed	O
via	O
jumpers	B-Device
,	O
DIP	O
switches	O
,	O
or	O
Plug-And-Play	B-Device
software	O
.	O
</s>
