<s>
OpenSimulator	B-Protocol
is	O
an	O
open-source	B-Application
server	B-Application
platform	O
originally	O
launched	O
in	O
2007	O
for	O
hosting	O
virtual	B-Application
worlds	I-Application
and	O
metaverse	O
environments	O
.	O
</s>
<s>
It	O
is	O
largely	O
compatible	O
with	O
the	O
virtual	B-Application
world	I-Application
Second	B-Application
Life	I-Application
but	O
full	O
compatibility	O
is	O
not	O
a	O
design	O
goal	O
.	O
</s>
<s>
OpenSimulator	B-Protocol
is	O
written	O
in	O
C#	B-Application
and	O
is	O
designed	O
to	O
be	O
easily	O
expanded	O
through	O
the	O
use	O
of	O
plugin	B-Application
modules	I-Application
.	O
</s>
<s>
OpenSimulator	B-Protocol
can	O
operate	O
in	O
one	O
of	O
two	O
modes	O
:	O
standalone	O
or	O
grid	O
mode	O
.	O
</s>
<s>
OpenSimulator	B-Protocol
uses	O
loadable	O
modules	O
for	O
most	O
of	O
its	O
functionality	O
.	O
</s>
<s>
These	O
loadable	O
modules	O
can	O
be	O
independently	O
developed	O
to	O
add	O
functionality	O
to	O
the	O
server	B-Application
.	O
</s>
<s>
OpenSimulator	B-Protocol
currently	O
uses	O
a	O
modified	O
Second	B-Application
Life	I-Application
protocol	O
for	O
client	O
to	O
server	B-Application
communication	O
,	O
and	O
requires	O
retrofitting	O
to	O
a	O
suitable	O
virtual	B-Application
world	I-Application
viewer	O
(	O
client	O
)	O
in	O
order	O
to	O
connect	O
.	O
</s>
<s>
Interoperability	O
with	O
Second	B-Application
Life	I-Application
protocols	O
was	O
initially	O
a	O
design	O
goal	O
.	O
</s>
<s>
During	O
the	O
OpenSimulator	B-Protocol
Community	O
Conference	O
2018	O
,	O
the	O
core	O
developers	O
announced	O
they	O
may	O
not	O
always	O
seek	O
to	O
maintain	O
compatibility	O
with	O
Linden	O
Lab	O
's	O
Second	B-Application
Life	I-Application
Protocols	O
,	O
and	O
may	O
change	O
or	O
add	O
facilities	O
in	O
line	O
with	O
differing	O
aims	O
.	O
</s>
<s>
OpenSim	O
has	O
a	O
number	O
of	O
features	O
not	O
available	O
in	O
Second	B-Application
Life	I-Application
.	O
</s>
<s>
These	O
include	O
virtual	B-Application
world	I-Application
content	O
(	O
OAR	O
)	O
and	O
avatar	O
inventory	O
(	O
IAR	O
)	O
save	O
and	O
load	O
capabilities	O
,	O
extensions	O
to	O
the	O
scripting	O
language	O
that	O
enable	O
saving	O
and	O
retrieval	O
of	O
text	O
data	O
to	O
avatar	O
inventory	O
in	O
notecard	O
format	O
and	O
the	O
creation	O
and	O
management	O
of	O
non-player	O
characters	O
(	O
NPCs	O
)	O
.	O
</s>
<s>
OpenSim	O
also	O
uses	O
an	O
architecture	O
known	O
as	O
"	O
Hypergrid	O
"	O
,	O
which	O
allows	O
users	O
to	O
teleport	O
between	O
multiple	O
OpenSim-based	O
virtual	B-Application
worlds	I-Application
by	O
providing	O
a	O
hyperlinked	O
map	O
which	O
indexes	O
public	O
grids	O
.	O
</s>
<s>
The	O
number	O
of	O
hypergrid-enabled	O
OpenSimulator	B-Protocol
grids	O
fluctuates	O
.	O
</s>
