<s>
In	O
grid	B-Architecture
computing	I-Architecture
,	O
a	O
virtual	B-Operating_System
organization	I-Operating_System
(	O
VO	O
)	O
refers	O
to	O
a	O
dynamic	O
set	O
of	O
individuals	O
or	O
institutions	O
defined	O
around	O
a	O
set	O
of	O
resource-sharing	B-General_Concept
rules	O
and	O
conditions	O
.	O
</s>
<s>
All	O
these	O
virtual	B-Operating_System
organizations	I-Operating_System
share	O
some	O
commonality	O
among	O
them	O
,	O
including	O
common	O
concerns	O
and	O
requirements	O
,	O
but	O
may	O
vary	O
in	O
size	O
,	O
scope	O
,	O
duration	O
,	O
sociology	O
,	O
and	O
structure	O
.	O
</s>
<s>
The	O
collaborations	O
involved	O
in	O
grid	B-Architecture
computing	I-Architecture
of	O
the	O
early	O
2000s	O
lead	O
to	O
the	O
emergence	O
of	O
multiple	O
organizations	O
that	O
function	O
as	O
one	O
unit	O
through	O
the	O
use	O
of	O
their	O
shared	O
competencies	O
and	O
resources	O
for	O
the	O
purpose	O
of	O
one	O
or	O
more	O
identified	O
goals	O
.	O
</s>
<s>
A	O
virtual	B-Operating_System
organization	I-Operating_System
has	O
the	O
characteristics	O
of	O
a	O
formal	O
organization	O
while	O
not	O
being	O
one	O
.	O
</s>
<s>
The	O
XtreemOS	O
project	O
promised	O
to	O
support	O
virtual	B-Operating_System
organizations	I-Operating_System
.	O
</s>
