<s>
The	O
Rio	B-Application
Receiver	I-Application
was	O
a	O
home	O
stereo	O
device	O
for	O
playing	O
MP3	B-Application
files	I-Application
stored	O
on	O
your	O
computer	O
's	O
hard	O
drive	O
over	O
an	O
Ethernet	O
or	O
HomePNA	B-Protocol
network	O
.	O
</s>
<s>
With	O
a	O
design	O
derived	O
from	O
the	O
existing	O
Linux-based	O
Empeg	B-Application
Car	I-Application
,	O
it	O
became	O
popular	O
among	O
the	O
Linux	B-Application
hacking	O
community	O
.	O
</s>
<s>
Network	O
connections	O
were	O
via	O
either	O
a	O
Cirrus	O
logic	O
8900A	O
(	O
10MBit	O
Ethernet	O
)	O
or	O
a	O
Broadcom	O
HomePNA	B-Protocol
10	O
Mbit/s	O
chipset	O
;	O
if	O
no	O
Ethernet	O
link	O
was	O
seen	O
at	O
boot	O
time	O
,	O
the	O
unit	O
tried	O
HomePNA	B-Protocol
.	O
</s>
<s>
The	O
user	O
interface	O
was	O
a	O
128x64	O
pixel	O
monochrome	O
LCD	B-Device
with	O
an	O
EL	O
backlight	O
,	O
a	O
rotary	O
control	O
with	O
a	O
push	O
button	O
,	O
several	O
buttons	O
and	O
IR	O
remote	O
control	O
.	O
</s>
<s>
The	O
unit	O
booted	O
via	O
a	O
2.2	O
linux	B-Application
kernel	O
in	O
flash	O
which	O
used	O
DHCP	B-Protocol
and	O
SSDP	O
to	O
discover	O
an	O
NFS	B-Protocol
server	O
from	O
which	O
it	O
loaded	O
a	O
new	O
kernel	O
.	O
</s>
<s>
The	O
second	O
kernel	O
then	O
mounted	O
a	O
root	O
filesystem	O
over	O
NFS	B-Protocol
containing	O
a	O
small	O
set	O
of	O
standard	O
POSIX	O
tools	O
and	O
an	O
application	O
for	O
selecting	O
and	O
playing	O
music	O
over	O
the	O
network	O
,	O
which	O
was	O
served	O
using	O
HTTP	B-Protocol
by	O
the	O
Audio	O
Receiver	O
Manager	O
software	O
running	O
on	O
a	O
Windows	O
PC	O
.	O
</s>
<s>
Although	O
the	O
music	O
player	O
and	O
the	O
Audio	O
Receiver	O
Manager	O
and	O
Broadcom	O
HomePNA	B-Protocol
kernel	O
driver	O
module	O
were	O
proprietary	O
software	O
,	O
the	O
kernel	O
and	O
other	O
tools	O
were	O
open	O
source	O
.	O
</s>
