<s>
The	O
SGI	B-Application
Origin	I-Application
2000	I-Application
is	O
a	O
family	O
of	O
mid-range	O
and	O
high-end	O
server	B-Application
computers	I-Application
developed	O
and	O
manufactured	O
by	O
Silicon	O
Graphics	O
(	O
SGI	O
)	O
.	O
</s>
<s>
They	O
were	O
introduced	O
in	O
1996	O
to	O
succeed	O
the	O
SGI	B-Application
Challenge	I-Application
and	O
POWER	O
Challenge	B-Application
.	O
</s>
<s>
At	O
the	O
time	O
of	O
introduction	O
,	O
these	O
ran	O
the	O
IRIX	B-Operating_System
operating	B-General_Concept
system	I-General_Concept
,	O
originally	O
version	O
6.4	O
and	O
later	O
,	O
6.5	O
.	O
</s>
<s>
A	O
variant	O
of	O
the	O
Origin	B-Application
2000	I-Application
with	O
graphics	O
capability	O
is	O
known	O
as	O
the	O
Onyx2	B-General_Concept
.	O
</s>
<s>
An	O
entry-level	O
variant	O
based	O
on	O
the	O
same	O
architecture	O
but	O
with	O
a	O
different	O
hardware	O
implementation	O
is	O
known	O
as	O
the	O
Origin	B-Application
200	I-Application
.	O
</s>
<s>
The	O
Origin	B-Application
2000	I-Application
was	O
succeeded	O
by	O
the	O
Origin	O
3000	O
in	O
July	O
2000	O
,	O
and	O
was	O
discontinued	O
on	O
June	O
30	O
,	O
2002	O
.	O
</s>
<s>
The	O
project	O
was	O
code	O
named	O
Lego	O
,	O
and	O
also	O
known	O
as	O
SN0	O
,	O
to	O
indicate	O
the	O
first	O
in	O
a	O
series	O
of	O
scalable	O
node	O
architectures	O
,	O
contrasting	O
with	O
previous	O
symmetric	B-Operating_System
multiprocessor	I-Operating_System
architectures	O
in	O
the	O
SGI	B-Application
Challenge	I-Application
series	O
.	O
</s>
<s>
The	O
highest	O
CPU	O
count	O
that	O
SGI	O
marketed	O
for	O
the	O
Origin	B-Application
2000	I-Application
is	O
128	O
CPUs	O
;	O
above	O
64	O
CPUs	O
the	O
product	O
was	O
originally	O
branded	O
"	O
CRAY	O
Origin	B-Application
2000	I-Application
"	O
since	O
Cray	O
Research	O
has	O
just	O
been	O
merged	O
with	O
SGI	O
.	O
</s>
<s>
Three	O
Origin	B-Application
2000	I-Application
models	O
are	O
capable	O
of	O
using	O
512	O
CPUs	O
and	O
512	O
GB	O
of	O
memory	O
but	O
these	O
were	O
never	O
marketed	O
as	O
a	O
system	O
to	O
customers	O
.	O
</s>
<s>
One	O
of	O
the	O
512-CPU	O
Origin	B-Application
2000	I-Application
series	O
was	O
installed	O
at	O
SGI	O
's	O
facility	O
in	O
Eagan	O
,	O
Minnesota	O
for	O
test	O
purposes	O
and	O
the	O
other	O
two	O
were	O
sold	O
to	O
NASA	O
Ames	O
Research	O
Center	O
in	O
Mountain	O
View	O
,	O
California	O
for	O
specialized	O
scientific	O
computing	O
.	O
</s>
<s>
Several	O
customers	O
also	O
bought	O
256-CPU	O
Origin	B-Application
2000	I-Application
series	O
systems	O
,	O
although	O
they	O
were	O
never	O
marketed	O
as	O
a	O
product	O
by	O
SGI	O
either	O
.	O
</s>
<s>
The	O
largest	O
installation	O
of	O
SGI	B-Application
Origin	I-Application
2000	I-Application
series	O
was	O
Accelerated	B-General_Concept
Strategic	I-General_Concept
Computing	I-General_Concept
Initiative	I-General_Concept
(	O
ASCI	O
)	O
Blue	B-Architecture
Mountain	I-Architecture
at	O
Los	O
Alamos	O
National	O
Labs	O
.	O
</s>
<s>
It	O
included	O
48	O
Origin	B-Application
2000	I-Application
series	O
128-CPU	O
systems	O
all	O
connected	O
via	O
High	B-Architecture
Performance	I-Architecture
Parallel	I-Architecture
Interface	I-Architecture
(	O
HIPPI	B-Architecture
)	O
for	O
a	O
total	O
of	O
6144	O
processors	O
.	O
</s>
<s>
At	O
the	O
time	O
it	O
was	O
tested	O
,	O
it	O
placed	O
second	O
on	O
the	O
TOP500	B-Operating_System
list	O
of	O
fastest	B-Operating_System
computers	I-Operating_System
in	O
the	O
world	O
.	O
</s>
<s>
The	O
climate	O
simulation	O
laboratory	O
at	O
the	O
National	O
Center	O
for	O
Atmospheric	O
Research	O
(	O
NCAR	O
)	O
had	O
an	O
Origin	B-Application
2000	I-Application
system	O
named	O
"	O
Ute	O
"	O
with	O
128	O
CPUs	O
.	O
</s>
<s>
Each	O
Origin	B-Application
2000	I-Application
module	O
is	O
based	O
on	O
nodes	O
that	O
are	O
plugged	O
into	O
a	O
backplane	B-Architecture
.	O
</s>
<s>
Each	O
module	O
can	O
contain	O
up	O
to	O
four	O
node	O
boards	O
,	O
two	O
router	O
boards	O
and	O
twelve	O
XIO	B-Architecture
options	O
.	O
</s>
<s>
The	O
Origin	B-Application
200	I-Application
uses	O
some	O
of	O
the	O
architectural	O
components	O
,	O
but	O
in	O
a	O
very	O
different	O
physical	O
realization	O
that	O
is	O
not	O
scalable	O
.	O
</s>
<s>
An	O
Origin	B-Application
2000	I-Application
system	O
is	O
composed	O
of	O
nodes	O
linked	O
together	O
by	O
an	O
interconnection	O
network	O
.	O
</s>
<s>
It	O
uses	O
the	O
distributed	B-Operating_System
shared	I-Operating_System
memory	I-Operating_System
sometimes	O
called	O
Scalable	O
Shared-Memory	O
Multiprocessing	O
(	O
S2MP	O
)	O
architecture	O
.	O
</s>
<s>
The	O
Origin	B-Application
2000	I-Application
uses	O
NUMAlink	B-Architecture
(	O
originally	O
named	O
CrayLink	B-Architecture
)	O
for	O
its	O
system	O
interconnect	O
.	O
</s>
<s>
The	O
nodes	O
are	O
connected	O
to	O
router	O
boards	O
,	O
which	O
use	O
NUMAlink	B-Architecture
cables	O
to	O
connect	O
to	O
other	O
nodes	O
through	O
their	O
routers	O
.	O
</s>
<s>
The	O
Origin	B-Application
2000	I-Application
's	O
network	O
topology	O
is	O
a	O
bristled	O
fat	O
hypercube	B-Operating_System
.	O
</s>
<s>
In	O
configurations	O
with	O
more	O
than	O
64	O
processors	O
,	O
a	O
hierarchical	O
fat	O
hypercube	B-Operating_System
network	O
topology	O
is	O
used	O
instead	O
.	O
</s>
<s>
Additional	O
NUMAlink	B-Architecture
cables	O
,	O
called	O
Xpress	O
links	O
can	O
be	O
installed	O
between	O
unused	O
Standard	O
Router	O
ports	O
to	O
reduce	O
latency	O
and	O
increase	O
bandwidth	O
.	O
</s>
<s>
The	O
architecture	O
has	O
its	O
roots	O
in	O
the	O
DASH	B-Operating_System
project	O
at	O
Stanford	O
University	O
,	O
led	O
by	O
John	O
L	O
.	O
Hennessy	O
,	O
which	O
included	O
two	O
of	O
the	O
Origin	O
designers	O
.	O
</s>
<s>
There	O
are	O
four	O
different	O
router	O
boards	O
used	O
by	O
the	O
Origin	B-Application
2000	I-Application
.	O
</s>
<s>
It	O
contains	O
an	O
application	O
specific	O
integrated	O
circuit	O
(	O
ASIC	O
)	O
known	O
as	O
the	O
scalable	O
pipelined	O
interconnect	O
for	O
distributed	O
endpoint	O
routing	O
(	O
SPIDER	O
)	O
,	O
which	O
serves	O
as	O
a	O
router	O
for	O
the	O
NUMAlink	B-Architecture
network	O
.	O
</s>
<s>
Each	O
Origin	B-Application
2000	I-Application
node	O
fits	O
on	O
a	O
single	O
16	O
"	O
by	O
11	O
"	O
printed	O
circuit	O
board	O
that	O
contains	O
one	O
or	O
two	O
processors	O
,	O
the	O
main	O
memory	O
,	O
the	O
directory	O
memory	O
and	O
the	O
Hub	O
ASIC	O
.	O
</s>
<s>
The	O
node	O
board	O
plugs	O
into	O
the	O
backplane	B-Architecture
through	O
a	O
300-pad	O
CPOP	O
(	O
Compression	O
Pad-on-Pad	O
)	O
connector	O
.	O
</s>
<s>
The	O
connector	O
actually	O
combines	O
two	O
connections	O
,	O
one	O
to	O
the	O
NUMAlink	B-Architecture
router	O
network	O
and	O
another	O
to	O
the	O
XIO	B-Architecture
I/O	O
subsystem	O
.	O
</s>
<s>
At	O
the	O
time	O
of	O
introduction	O
,	O
the	O
Origin	B-Application
2000	I-Application
used	O
the	O
IP27	O
board	O
,	O
featuring	O
one	O
or	O
two	O
R10000	B-General_Concept
processors	O
clocked	O
at	O
180MHz	O
with	O
1	O
MB	O
secondary	O
cache(s )	O
.	O
</s>
<s>
A	O
high-end	O
model	O
with	O
two	O
195MHz	O
R10000	B-General_Concept
processors	O
with	O
4	O
MB	O
secondary	O
caches	O
was	O
also	O
available	O
.	O
</s>
<s>
In	O
February	O
1998	O
,	O
the	O
IP31	O
board	O
was	O
introduced	O
with	O
two	O
250MHz	O
R10000	B-General_Concept
processors	O
with	O
4	O
MB	O
secondary	O
caches	O
.	O
</s>
<s>
Later	O
,	O
the	O
IP31	O
board	O
was	O
upgraded	O
to	O
support	O
two	O
300	O
,	O
350	O
or	O
400MHz	O
R12000	B-General_Concept
processors	O
.	O
</s>
<s>
Near	O
the	O
end	O
of	O
its	O
life	O
,	O
a	O
variant	O
of	O
the	O
IP31	O
board	O
that	O
could	O
utilize	O
the	O
500MHz	O
R14000	B-General_Concept
with	O
8	O
MB	O
L2	O
caches	O
was	O
made	O
available	O
.	O
</s>
<s>
Each	O
node	O
board	O
can	O
support	O
a	O
maximum	O
of	O
4	O
GB	O
of	O
memory	O
through	O
16	O
DIMM	B-General_Concept
slots	O
by	O
using	O
proprietary	O
ECC	B-General_Concept
memory	I-General_Concept
SDRAM	O
DIMMs	B-General_Concept
with	O
capacities	O
of	O
16	O
,	O
32	O
,	O
64	O
and	O
256	O
MB	O
.	O
</s>
<s>
To	O
support	O
the	O
Origin	B-Application
2000	I-Application
distributed	B-Operating_System
shared	I-Operating_System
memory	I-Operating_System
model	O
,	O
the	O
memory	O
modules	O
are	O
proprietary	O
and	O
include	O
directory	O
memory	O
,	O
which	O
contains	O
information	O
on	O
the	O
contents	O
of	O
remote	O
caches	O
for	O
maintaining	O
cache	B-General_Concept
coherency	I-General_Concept
,	O
supporting	O
up	O
to	O
32	O
processors	O
.	O
</s>
<s>
The	O
additional	O
directory	O
memory	O
is	O
contained	O
on	O
proprietary	O
DIMMs	B-General_Concept
that	O
are	O
inserted	O
into	O
eight	O
DIMM	B-General_Concept
slots	O
set	O
aside	O
for	O
its	O
use	O
.	O
</s>
<s>
The	O
Hub	O
ASIC	O
interfaces	O
the	O
processors	O
,	O
memory	O
and	O
XIO	B-Architecture
to	O
the	O
NUMAlink	B-Architecture
2	O
system	O
interconnect	O
.	O
</s>
<s>
The	O
interfaces	O
communicate	O
with	O
each	O
other	O
via	O
FIFO	B-Operating_System
buffers	O
that	O
are	O
connected	O
to	O
the	O
crossbar	O
.	O
</s>
<s>
When	O
two	O
processors	O
are	O
connected	O
to	O
the	O
Hub	O
ASIC	O
,	O
the	O
node	O
does	O
not	O
behave	O
in	O
a	O
SMP	B-Operating_System
fashion	O
.	O
</s>
<s>
Instead	O
,	O
the	O
two	O
processors	O
operate	O
separately	O
and	O
their	O
buses	O
are	O
multiplexed	B-Architecture
over	O
the	O
single	O
processor	O
interface	O
.	O
</s>
<s>
Since	O
the	O
Xbow	O
ASIC	O
is	O
intended	O
for	O
use	O
with	O
the	O
simpler	O
XIO	B-Architecture
protocol	O
,	O
its	O
hardware	O
is	O
also	O
simpler	O
,	O
allowing	O
the	O
ASIC	O
to	O
feature	O
eight	O
ports	O
,	O
compared	O
with	O
the	O
SPIDER	O
ASIC	O
's	O
six	O
ports	O
.	O
</s>
<s>
Two	O
of	O
the	O
ports	O
connect	O
to	O
the	O
node	O
boards	O
,	O
and	O
the	O
remaining	O
six	O
to	O
XIO	B-Architecture
cards	O
.	O
</s>
<s>
While	O
the	O
I/O	O
subsystem	O
's	O
native	O
bus	O
is	O
XIO	B-Architecture
,	O
PCI-X	O
and	O
VME64	B-Architecture
buses	O
can	O
also	O
be	O
used	O
,	O
provided	O
by	O
XIO	B-Architecture
bridges	O
.	O
</s>
<s>
It	O
is	O
a	O
XIO	B-Architecture
card	O
that	O
provides	O
:	O
</s>
<s>
The	O
IO6G	O
(	O
G	O
for	O
Graphics	O
)	O
had	O
2	O
additional	O
serial	B-Protocol
ports	I-Protocol
and	O
keyboard/mouse	O
ports	O
plus	O
the	O
above	O
ports	O
.	O
</s>
<s>
The	O
IO6G	O
was	O
required	O
on	O
systems	O
with	O
the	O
Onyx	B-General_Concept
Graphics	O
pipes(cards )	O
to	O
connect	O
keyboard/mouse	O
.	O
</s>
