<s>
Open	B-Protocol
Cobalt	I-Protocol
is	O
a	O
free	B-License
and	I-License
open-source	I-License
software	I-License
platform	O
for	O
constructing	O
,	O
accessing	O
,	O
and	O
sharing	O
virtual	B-Application
worlds	I-Application
both	O
on	O
local	B-General_Concept
area	I-General_Concept
networks	I-General_Concept
or	O
across	O
the	O
Internet	O
,	O
with	O
no	O
need	O
for	O
centralized	O
servers	O
.	O
</s>
<s>
The	O
technology	O
makes	O
it	O
easy	O
to	O
create	O
deeply	O
collaborative	O
and	O
hyperlinked	O
multi-user	O
virtual	O
workspaces	O
,	O
virtual	O
exhibit	O
spaces	O
,	O
and	O
game-based	O
learning	O
and	O
training	O
environments	O
that	O
run	O
on	O
all	O
major	O
software	O
operating	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
By	O
using	O
a	O
peer-to-peer-based	O
message	B-Architecture
passing	I-Architecture
protocol	O
to	O
reduce	O
reliance	O
on	O
server	O
infrastructures	O
for	O
support	O
of	O
basic	O
in-world	O
interactions	O
across	O
many	O
participants	O
,	O
Open	B-Protocol
Cobalt	I-Protocol
makes	O
it	O
possible	O
for	O
people	O
to	O
hyperlink	O
their	O
virtual	B-Application
worlds	I-Application
via	O
3D	O
portals	O
to	O
form	O
a	O
large	O
distributed	B-Architecture
network	B-Architecture
of	O
interconnected	O
collaboration	O
spaces	O
.	O
</s>
<s>
It	O
also	O
makes	O
it	O
possible	O
for	O
schools	O
and	O
other	O
organizations	O
to	O
freely	O
set	O
up	O
their	O
own	O
networks	O
of	O
public	O
and	O
private	O
3D	O
virtual	O
workspaces	O
that	O
feature	O
integrated	O
web	O
browsing	O
,	O
voice	B-Protocol
chat	I-Protocol
,	O
text	B-Protocol
chat	I-Protocol
,	O
and	O
access	O
to	O
remote	B-Protocol
desktop	I-Protocol
applications	O
and	O
services	O
.	O
</s>
<s>
Open	B-Protocol
Cobalt	I-Protocol
uses	O
the	O
Squeak	B-Operating_System
software	O
environment	O
,	O
which	O
is	O
an	O
open-source	B-Application
Smalltalk	B-Application
system	O
freely	O
available	O
for	O
Windows	B-Application
,	O
Mac	O
and	O
Unix	O
.	O
</s>
<s>
As	O
is	O
true	O
of	O
almost	O
any	O
Smalltalk	B-Application
application	B-Application
,	O
Open	B-Protocol
Cobalt	I-Protocol
has	O
identical	O
functioning	O
on	O
any	O
supported	O
platform	O
.	O
</s>
<s>
As	O
a	O
Smalltalk	B-Application
system	O
,	O
it	O
can	O
usually	O
be	O
updated	O
while	O
the	O
system	O
is	O
running	O
without	O
needing	O
a	O
restart	O
.	O
</s>
<s>
Open	B-Protocol
Cobalt	I-Protocol
is	O
designed	O
to	O
enable	O
the	O
deployment	O
of	O
secure	O
virtual	B-Application
world	I-Application
spaces	O
that	O
support	O
education	O
,	O
research	O
,	O
and	O
the	O
activities	O
of	O
virtual	O
organizations	O
.	O
</s>
<s>
By	O
leveraging	O
OpenGL-based	O
3D	O
graphics	O
,	O
Open	B-Protocol
Cobalt	I-Protocol
supports	O
highly	O
scalable	O
collaborative	O
data	B-Application
visualization	I-Application
,	O
virtual	O
learning	O
and	O
problem	O
solving	O
environments	O
,	O
3D	O
wikis	O
,	O
online	O
gaming	O
environments	O
termed	O
Massively	B-Protocol
multiplayer	I-Protocol
online	I-Protocol
role-playing	I-Protocol
games	I-Protocol
(	O
MMORPGs	B-Protocol
)	O
,	O
and	O
privately	O
and	O
securely	O
maintained	O
multi-user	B-Application
virtual	I-Application
environments	I-Application
.	O
</s>
<s>
The	O
Open	B-Protocol
Cobalt	I-Protocol
application	B-Application
leverages	O
peer-based	O
messaging	O
to	O
eliminate	O
the	O
need	O
for	O
virtual	B-Application
world	I-Application
servers/commercial	O
services	O
and	O
makes	O
it	O
very	O
simple	O
for	O
end-users	O
to	O
create	O
and	O
securely	O
share	O
deeply	O
collaborative	O
virtual	B-Application
worlds	I-Application
that	O
run	O
on	O
all	O
major	O
software	O
operating	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
Users	O
moving	O
through	O
and	O
interacting	O
within	O
Open	B-Protocol
Cobalt	I-Protocol
worlds	O
simultaneously	O
participate	O
and	O
collaborate	O
in	O
a	O
dynamic	O
,	O
concurrent	O
environment	O
where	O
they	O
can	O
work	O
,	O
explore	O
,	O
and	O
learn	O
at	O
a	O
level	O
of	O
integration	O
and	O
extensibility	O
not	O
easily	O
achieved	O
through	O
commercial	O
virtual	B-Application
world	I-Application
technologies	O
.	O
</s>
<s>
Open	B-Protocol
Cobalt	I-Protocol
is	O
derived	O
from	O
the	O
Croquet	B-Protocol
software	B-Application
development	I-Application
kit	I-Application
(	O
SDK	O
)	O
that	O
was	O
publicly	O
released	O
under	O
the	B-License
MIT	I-License
License	I-License
by	O
Hewlett-Packard	O
and	O
the	O
Croquet	B-Protocol
Consortium	O
in	O
early	O
2007	O
.	O
</s>
<s>
In	O
early	O
2008	O
,	O
and	O
with	O
the	O
support	O
of	O
the	O
Andrew	O
W	O
.	O
Mellon	O
Foundation	O
,	O
Julian	O
Lombardi	O
and	O
Mark	O
P	O
.	O
McCahill	O
,	O
at	O
Duke	O
University	O
,	O
launched	O
the	O
community-based	O
software	O
development	O
effort	O
to	O
build	O
Open	B-Protocol
Cobalt	I-Protocol
as	O
an	O
open-source	B-Application
virtual	B-Application
world	I-Application
browser	O
application	B-Application
and	O
construction	O
toolkit	O
.	O
</s>
<s>
In	O
May	O
2008	O
,	O
Lombardi	O
was	O
awarded	O
a	O
National	O
Science	O
Foundation	O
grant	O
to	O
further	O
strengthen	O
the	O
community-based	O
software	O
development	O
effort	O
and	O
bring	O
the	O
Open	B-Protocol
Cobalt	I-Protocol
virtual	B-Application
world	I-Application
browser	O
to	O
its	O
alpha	O
release	O
.	O
</s>
<s>
Together	O
with	O
John	O
Dougan	O
as	O
technical	O
project	O
lead	O
and	O
a	O
growing	O
international	O
community	O
of	O
software	O
developers	O
and	O
volunteers	O
,	O
the	O
Open	B-Protocol
Cobalt	I-Protocol
project	O
contributors	O
released	O
Open	B-Protocol
Cobalt	I-Protocol
Alpha	O
in	O
April	O
2010	O
.	O
</s>
<s>
Recent	O
activity	O
involving	O
the	O
project	O
can	O
be	O
found	O
in	O
the	O
Open	B-Protocol
Cobalt	I-Protocol
Google	B-Application
Group	O
.	O
</s>
<s>
The	O
goals	O
of	O
the	O
Open	B-Protocol
Cobalt	I-Protocol
effort	O
are	O
to	O
stimulate	O
the	O
use	O
of	O
distributed	B-Architecture
virtual	O
environments	O
,	O
advance	O
visual	O
simulations	O
,	O
and	O
deepen	O
collaboration	O
in	O
education	O
,	O
research	O
,	O
and	O
personal	O
entertainment	O
-	O
and	O
in	O
so	O
doing	O
to	O
:	O
</s>
<s>
Open	B-Protocol
Cobalt	I-Protocol
is	O
both	O
an	O
end-user	O
application	B-Application
and	O
full	O
featured	O
software	B-Application
development	I-Application
environment	I-Application
for	O
creating	O
a	O
rich	O
network	B-Architecture
of	O
end-user	O
created	O
interlinked	O
virtual	B-Application
worlds	I-Application
.	O
</s>
<s>
It	O
is	O
more	O
extensible	O
than	O
the	O
proprietary	O
technologies	O
behind	O
collaborative	O
worlds	O
such	O
as	O
Second	B-Application
Life	I-Application
,	O
and	O
before	O
that	O
ViOS	O
.	O
</s>
<s>
Unlike	O
most	O
other	O
virtual	B-Application
world	I-Application
platforms	O
(	O
with	O
the	O
exception	O
of	O
OpenSimulator	B-Protocol
's	O
Hypergrid	O
architecture	O
)	O
,	O
Open	B-Protocol
Cobalt	I-Protocol
uses	O
a	O
method	O
of	O
hyperlinking	O
,	O
known	O
as	O
"	O
space-linking	O
"	O
,	O
which	O
resembles	O
a	O
window	O
frame	O
or	O
portal	O
and	O
,	O
when	O
revolved	O
,	O
shows	O
a	O
360-degree	O
real-time	O
view	O
of	O
one	O
region	O
to	O
a	O
user	O
in	O
another	O
region	O
;	O
such	O
portals	O
can	O
also	O
be	O
walked	O
through	O
by	O
users	O
.	O
</s>
<s>
Like	O
MediaWiki	B-Application
's	O
redlinks	O
,	O
such	O
portals	O
are	O
also	O
used	O
to	O
link	O
to	O
uncreated	O
spaces	O
or	O
regions	O
(	O
colored	O
in	O
black	O
)	O
in	O
order	O
to	O
indicate	O
the	O
need	O
to	O
create	O
newer	O
spaces	O
.	O
</s>
<s>
Open	B-Protocol
Cobalt	I-Protocol
is	O
an	O
application	B-Application
built	O
using	O
the	O
Open	B-Protocol
Croquet	I-Protocol
software	O
developer	O
's	O
toolkit	O
.	O
</s>
<s>
Its	O
relationship	O
to	O
Open	B-Protocol
Croquet	I-Protocol
provides	O
it	O
with	O
a	O
number	O
of	O
powerful	O
capabilities	O
.	O
</s>
<s>
Open	B-Protocol
Cobalt	I-Protocol
's	O
software	B-Application
development	I-Application
environment	I-Application
enables	O
programmers	O
to	O
enjoy	O
the	O
capabilities	O
of	O
a	O
true	O
late	O
bound	O
,	O
message	O
sending	O
language	O
.	O
</s>
<s>
Because	O
it	O
is	O
built	O
on	O
Squeak/Croquet	O
,	O
Open	B-Protocol
Cobalt	I-Protocol
is	O
a	O
purely	O
object-oriented	B-Language
programming	I-Language
system	I-Language
that	O
allows	O
for	O
significant	O
flexibility	O
in	O
its	O
design	O
and	O
implementation	O
.	O
</s>
<s>
Within	O
Open	B-Protocol
Cobalt	I-Protocol
,	O
programmers	O
may	O
edit	O
the	O
source	O
code	O
of	O
the	O
3D	O
world	O
from	O
within	O
the	O
world	O
,	O
and	O
immediately	O
see	O
the	O
result	O
while	O
the	O
world	O
is	O
still	O
running	O
.	O
</s>
<s>
Any	O
part	O
of	O
the	O
program	O
may	O
be	O
edited	O
,	O
down	O
to	O
the	O
virtual	B-Architecture
machine	I-Architecture
(	O
VM	O
)	O
and	O
OpenGL	B-Application
calls	O
.	O
</s>
<s>
Open	B-Protocol
Cobalt	I-Protocol
's	O
reliance	O
on	O
Squeak	B-Operating_System
's	O
generalized	O
storage	O
allocator	O
and	O
garbage	B-General_Concept
collector	I-General_Concept
makes	O
it	O
highly	O
efficient	O
in	O
real-time	O
and	O
allows	O
reshaping	O
of	O
objects	B-Language
to	O
be	O
done	O
safely	O
.	O
</s>
<s>
As	O
with	O
Squeak	B-Operating_System
,	O
Open	B-Protocol
Cobalt	I-Protocol
supports	O
many	O
non-English	O
languages	O
and	O
fonts	O
such	O
as	O
German	O
,	O
Spanish	O
,	O
French	O
,	O
and	O
Japanese	O
.	O
</s>
<s>
Underlying	O
Open	B-Protocol
Cobalt	I-Protocol
is	O
an	O
object-oriented	B-Language
semantics	O
based	O
on	O
active	O
objects	B-Language
that	O
have	O
the	O
capability	O
of	O
temporal	O
reflection	B-Language
.	O
</s>
<s>
Open	B-Protocol
Cobalt	I-Protocol
also	O
directly	O
supports	O
replication	O
of	O
computation	O
,	O
allowing	O
computation	O
to	O
be	O
moved	O
close	O
to	O
the	O
point	O
of	O
interaction	O
on	O
demand	O
,	O
while	O
maintaining	O
a	O
consistent	O
view	O
of	O
behaviors	O
that	O
can	O
scale	O
to	O
include	O
thousands	O
of	O
nodes	O
.	O
</s>
<s>
It	O
does	O
this	O
by	O
using	O
a	O
combination	O
of	O
object	O
semantics	O
along	O
with	O
a	O
modified	O
version	O
of	O
David	O
P	O
.	O
Reed	O
's	O
TeaTime	O
peer-based	O
messaging	O
protocol	O
as	O
a	O
distributed	B-Architecture
message	O
transactional	O
system	O
enabling	O
replicated	O
computation	O
(	O
synchronization	O
)	O
across	O
multiple	O
peers	O
.	O
</s>
<s>
Owing	O
to	O
these	O
properties	O
,	O
software	O
developers	O
can	O
use	O
Open	B-Protocol
Cobalt	I-Protocol
as	O
a	O
way	O
of	O
creating	O
deeply	O
collaborative	O
applications	O
without	O
the	O
effort	O
needed	O
to	O
understand	O
how	O
replicated	O
applications	O
work	O
.	O
</s>
<s>
It	O
also	O
makes	O
it	O
possible	O
to	O
deploy	O
and	O
coordinate	O
the	O
activities	O
of	O
virtual	B-Application
worlds	I-Application
on	O
multiple	O
machines	O
without	O
the	O
need	O
to	O
maintain	O
central	O
server	O
resources	O
(	O
other	O
than	O
those	O
needed	O
for	O
specialized	O
data	O
and	O
institutional	O
middleware	O
services	O
)	O
.	O
</s>
<s>
Open	B-Protocol
Cobalt	I-Protocol
's	O
implementation	O
of	O
TeaTime	O
includes	O
:	O
</s>
<s>
Replicated	O
,	O
versioned	O
objects	B-Language
that	O
unify	O
replicated	O
computation	O
and	O
distribution	O
of	O
results	O
,	O
</s>
<s>
Replication	O
strategies	O
that	O
separate	O
the	O
mechanisms	O
of	O
replication	O
from	O
the	O
behavioral	O
semantics	O
of	O
objects	B-Language
,	O
</s>
<s>
Coordinated	O
,	O
distributed	B-Architecture
two-phase	B-General_Concept
commit	I-General_Concept
that	O
is	O
used	O
to	O
control	O
the	O
progress	O
of	O
computations	O
at	O
multiple	O
sites	O
,	O
to	O
provide	O
resilience	O
,	O
deterministic	O
results	O
,	O
and	O
adaptation	O
to	O
available	O
resources	O
,	O
</s>
<s>
Use	O
of	O
distributed	B-Architecture
sets	O
.	O
</s>
