<s>
Rocks	B-Operating_System
Cluster	I-Operating_System
Distribution	I-Operating_System
(	O
originally	O
NPACI	O
Rocks	O
)	O
is	O
a	O
Linux	B-Application
distribution	I-Application
intended	O
for	O
high-performance	B-Architecture
computing	I-Architecture
(	O
HPC	O
)	O
clusters	B-Architecture
.	O
</s>
<s>
It	O
was	O
started	O
by	O
National	O
Partnership	O
for	O
Advanced	O
Computational	O
Infrastructure	O
and	O
the	O
San	O
Diego	O
Supercomputer	B-Architecture
Center	O
(	O
SDSC	O
)	O
in	O
2000	O
.	O
</s>
<s>
Rocks	O
was	O
initially	O
based	O
on	O
the	O
Red	O
Hat	O
Linux	B-Operating_System
(	O
RHL	O
)	O
distribution	O
,	O
however	O
modern	O
versions	O
of	O
Rocks	O
were	O
based	O
on	O
CentOS	O
,	O
with	O
a	O
modified	O
Anaconda	B-Language
installer	I-Language
that	O
simplifies	O
mass	O
installation	O
onto	O
many	O
computers	O
.	O
</s>
<s>
Rocks	O
includes	O
many	O
tools	O
(	O
such	O
as	O
Message	B-Application
Passing	I-Application
Interface	I-Application
(	O
MPI	O
)	O
)	O
which	O
are	O
not	O
part	O
of	O
CentOS	O
but	O
are	O
integral	O
components	O
that	O
make	O
a	O
group	O
of	O
computers	O
into	O
a	O
cluster	O
.	O
</s>
<s>
Over	O
a	O
dozen	O
Rolls	O
have	O
been	O
created	O
,	O
including	O
the	O
Sun	B-Operating_System
Grid	I-Operating_System
Engine	I-Operating_System
(	O
SGE	O
)	O
roll	O
,	O
the	O
Condor	B-Operating_System
roll	O
,	O
the	O
Lustre	B-Application
roll	O
,	O
the	O
Java	B-Device
roll	O
,	O
and	O
the	O
Ganglia	B-Language
roll	O
.	O
</s>
<s>
By	O
October	O
2010	O
,	O
Rocks	O
was	O
used	O
for	O
academic	O
,	O
government	O
,	O
and	O
commercial	O
organizations	O
,	O
employed	O
in	O
1,376	O
clusters	B-Architecture
,	O
on	O
every	O
continent	O
except	O
Antarctica	O
.	O
</s>
<s>
The	O
largest	O
registered	O
academic	O
cluster	O
,	O
having	O
8632	O
CPUs	O
,	O
is	O
GridKa	O
,	O
operated	O
by	O
the	O
Karlsruhe	B-Algorithm
Institute	O
of	O
Technology	O
in	O
Karlsruhe	B-Algorithm
,	O
Germany	O
.	O
</s>
<s>
There	O
are	O
also	O
a	O
number	O
of	O
clusters	B-Architecture
ranging	O
down	O
to	O
fewer	O
than	O
10	O
CPUs	O
,	O
representing	O
the	O
early	O
stages	O
in	O
the	O
construction	O
of	O
larger	O
systems	O
,	O
as	O
well	O
as	O
being	O
used	O
for	O
courses	O
in	O
cluster	O
design	O
.	O
</s>
