<s>
SMCS	B-General_Concept
,	O
the	O
Submarine	B-General_Concept
Command	I-General_Concept
System	I-General_Concept
,	O
was	O
first	O
created	O
for	O
the	O
Royal	O
Navy	O
of	O
the	O
United	O
Kingdom	O
's	O
s	O
as	O
a	O
tactical	O
information	O
system	O
and	O
a	O
torpedo	O
weapon	O
control	O
system	O
.	O
</s>
<s>
The	O
consortium	O
proposed	O
a	O
novel	O
distributed	O
processing	O
system	O
based	O
on	O
commercial	O
off-the-shelf	O
(	O
COTS	O
)	O
processors	O
,	O
with	O
a	O
modular	O
software	O
architecture	O
largely	O
written	O
in	O
the	O
Ada	B-Language
programming	I-Language
language	I-Language
.	O
</s>
<s>
Each	O
set	O
of	O
Initial	O
Phase	O
SMCS	B-General_Concept
equipment	O
has	O
multiple	O
computer	O
nodes	O
.	O
</s>
<s>
Each	O
central	O
node	O
is	O
duplicated	O
to	O
create	O
a	O
fault-tolerant	B-General_Concept
system	I-General_Concept
which	O
is	O
dual	B-Error_Name
modular	I-Error_Name
redundant	I-Error_Name
.	O
</s>
<s>
In	O
the	O
Initial	O
Phase	O
equipment	O
fitted	O
to	O
the	O
s	O
most	O
processing	O
is	O
done	O
by	O
Intel	B-General_Concept
80386	I-General_Concept
single-board	B-Device
computers	I-Device
,	O
each	O
with	O
its	O
own	O
Ada	B-Language
run-time	O
environment	O
.	O
</s>
<s>
CAP	O
Scientific	O
created	O
a	O
complex	O
layer	O
of	O
middleware	B-General_Concept
to	O
link	O
the	O
many	O
processors	O
together	O
.	O
</s>
<s>
At	O
its	O
time	O
SMCS	B-General_Concept
was	O
the	O
largest	O
Ada	B-Language
project	O
so	O
far	O
seen	O
.	O
</s>
<s>
As	O
a	O
pioneering	O
user	O
of	O
Ada	B-Language
,	O
the	O
SMCS	B-General_Concept
project	O
encountered	O
many	O
teething	O
problems	O
with	O
the	O
large-scale	O
use	O
of	O
Ada	B-Language
compilers	O
,	O
Ada	B-Language
development	O
tools	O
,	O
and	O
the	O
special	O
characteristics	O
of	O
the	O
early	O
dialect	O
of	O
the	O
Ada	B-Language
programming	I-Language
language	I-Language
,	O
later	O
known	O
as	O
Ada	B-Language
83	I-Language
.	O
</s>
<s>
By	O
1991	O
,	O
CAP	O
Scientific	O
was	O
part	O
of	O
Sema	O
Group	O
and	O
the	O
SMCS	B-General_Concept
project	O
was	O
owned	O
by	O
BAeSEMA	O
,	O
a	O
joint	O
venture	O
between	O
Sema	O
Group	O
and	O
British	O
Aerospace	O
.	O
</s>
<s>
Once	O
SMCS	B-General_Concept
was	O
proven	O
to	O
work	O
on	O
Vanguard	O
boats	O
,	O
it	O
was	O
proposed	O
in	O
the	O
early	O
1990s	O
to	O
extend	O
its	O
use	O
to	O
the	O
s	O
and	O
the	O
s	O
,	O
as	O
part	O
of	O
an	O
improvement	O
programme	O
for	O
these	O
vessels	O
.	O
</s>
<s>
The	O
consensus	O
was	O
to	O
port	O
SMCS	B-General_Concept
to	O
some	O
form	O
of	O
UNIX	B-Application
.	O
</s>
<s>
Sema	O
Group	O
,	O
with	O
considerable	O
experience	O
both	O
of	O
real-time	O
systems	O
and	O
of	O
commercial	O
UNIX	B-Application
,	O
had	O
concerns	O
about	O
the	O
technological	O
feasibility	O
of	O
this	O
port	O
.	O
</s>
<s>
The	O
essence	O
of	O
the	O
problem	O
was	O
the	O
need	O
to	O
map	O
the	O
Ada	B-Language
tasking	O
environment	O
to	O
the	O
run-time	O
model	O
of	O
UNIX	B-Application
processes	O
in	O
a	O
way	O
which	O
preserved	O
SMCS	B-General_Concept
 '	O
real-time	O
characteristics	O
enough	O
to	O
maintain	O
dependability	B-Application
.	O
</s>
<s>
A	O
team	O
from	O
BAeSEMA	O
,	O
led	O
by	O
Ray	O
Foulkes	O
,	O
conducted	O
thorough	O
research	O
into	O
possible	O
alternatives	O
to	O
the	O
distributed	O
Ada	B-Language
architecture	O
used	O
in	O
the	O
Initial	O
phase	O
.	O
</s>
<s>
After	O
extensive	O
investigation	O
of	O
the	O
run-time	O
behaviour	O
of	O
different	O
UNIX	B-Application
variants	O
,	O
and	O
of	O
the	O
code	O
generated	O
by	O
different	O
Ada	B-Language
compilers	O
,	O
the	O
project	O
selected	O
the	O
Solaris	B-Application
operating	I-Application
system	I-Application
running	O
on	O
SPARC	B-Architecture
computers	O
,	O
which	O
could	O
now	O
be	O
procured	O
as	O
COTS	O
single-board	B-Device
computers	I-Device
.	O
</s>
<s>
To	O
limit	O
risk	O
,	O
only	O
the	O
consoles	O
were	O
converted	O
to	O
Solaris	B-Application
on	O
SPARC	B-Architecture
in	O
this	O
phase	O
.	O
</s>
<s>
The	O
benefit	O
was	O
that	O
there	O
was	O
no	O
need	O
to	O
implement	O
the	O
dual	B-Error_Name
modular	I-Error_Name
redundancy	I-Error_Name
scheme	O
on	O
Solaris	B-Application
at	O
this	O
stage	O
.	O
</s>
<s>
However	O
,	O
the	O
project	O
had	O
to	O
manage	O
some	O
additional	O
issues	O
arising	O
from	O
mixed	O
intel/SPARC	O
working	O
,	O
such	O
as	O
endianism	O
(	O
since	O
intel	O
architecture	O
is	O
little-endian	O
and	O
SPARC	B-Architecture
is	O
big-endian	O
)	O
.	O
</s>
<s>
A	O
detailed	O
and	O
generally	O
accurate	O
independent	O
analysis	O
of	O
these	O
stages	O
in	O
the	O
development	O
of	O
SMCS	B-General_Concept
was	O
made	O
in	O
1998	O
.	O
</s>
<s>
After	O
being	O
successfully	O
deployed	O
on	O
the	O
Swiftsure	O
and	O
Trafalgar	O
submarines	O
in	O
the	O
mixed	O
Intel/SPARC	O
configuration	O
,	O
the	O
architecture	O
was	O
further	O
revised	O
for	O
the	O
UK	O
's	O
new	O
attack	O
boats	O
,	O
the	O
s	O
.	O
</s>
<s>
The	O
Astute	O
Combat	O
Management	O
System	O
(	O
ACMS	O
)	O
combines	O
SMCS	B-General_Concept
with	O
several	O
other	O
sub-systems	O
.	O
</s>
<s>
For	O
ACMS	O
,	O
the	O
Central	O
Nodes	O
have	O
also	O
been	O
converted	O
to	O
SPARC	B-Architecture
computers	O
.	O
</s>
<s>
There	O
are	O
about	O
twice	O
as	O
many	O
consoles	O
as	O
provided	O
in	O
earlier	O
versions	O
of	O
SMCS	B-General_Concept
.	O
</s>
<s>
This	O
phase	O
of	O
SMCS	B-General_Concept
is	O
an	O
all-UNIX	O
solution	O
running	O
Solaris	B-Application
on	O
multiple	O
SPARC	B-Architecture
nodes	O
,	O
with	O
built-in	O
dual	O
redundancy	O
.	O
</s>
<s>
By	O
2000	O
,	O
Sema	O
Group	O
had	O
sold	O
its	O
interest	O
in	O
BAeSEMA	O
,	O
and	O
the	O
SMCS	B-General_Concept
project	O
was	O
now	O
fully	O
owned	O
by	O
BAE	O
Systems	O
.	O
</s>
<s>
It	O
was	O
expected	O
that	O
the	O
SMCS	B-General_Concept
equipment	O
,	O
supplied	O
and	O
maintained	O
under	O
a	O
support	O
contract	O
with	O
Ultra	O
Electronics	O
,	O
would	O
last	O
out	O
the	O
service	O
life	O
of	O
the	O
Vanguard	O
fleet	O
.	O
</s>
<s>
For	O
a	O
brief	O
period	O
,	O
the	O
SMCS	B-General_Concept
project	O
came	O
under	O
the	O
ownership	O
of	O
Alenia	O
Marconi	O
Systems	O
,	O
a	O
joint	O
venture	O
of	O
BAE	O
Systems	O
.	O
</s>
<s>
In	O
2002	O
,	O
it	O
was	O
proposed	O
to	O
convert	O
SMCS	B-General_Concept
to	O
run	O
on	O
standard	O
PC	O
x86	B-Operating_System
hardware	O
,	O
albeit	O
in	O
rugged	O
industrialised	O
form	O
,	O
for	O
naval	O
command	O
systems	O
.	O
</s>
<s>
The	O
SMCS	B-General_Concept
project	O
started	O
to	O
develop	O
SMCS-NG	O
(	O
"	O
Next	O
Generation	O
"	O
)	O
as	O
SMCS	B-General_Concept
running	O
on	O
PC	O
hardware	O
.	O
</s>
<s>
The	O
plan	O
was	O
to	O
convert	O
the	O
SMCS	B-General_Concept
infrastructure	O
and	O
applications	O
to	O
run	O
on	O
the	O
Microsoft	B-Application
Windows	I-Application
operating	I-Application
system	I-Application
.	O
</s>
<s>
Gates	O
 '	O
testimony	O
included	O
statements	O
that	O
Microsoft	B-Application
Windows	I-Application
was	O
indissoluble	O
and	O
could	O
not	O
be	O
created	O
in	O
cut-down	O
form	O
.	O
</s>
<s>
Assuming	O
Gates	O
 '	O
testimony	O
to	O
be	O
true	O
,	O
these	O
'	O
pro-UNIX	O
'	O
engineers	O
felt	O
that	O
open-source	O
UNIX	B-Application
,	O
rather	O
than	O
Microsoft	B-Application
Windows	I-Application
,	O
should	O
be	O
used	O
as	O
the	O
foundation	O
of	O
future	O
naval	O
command	O
systems	O
and	O
circulated	O
their	O
concerns	O
within	O
the	O
company	O
.	O
</s>
<s>
Despite	O
the	O
concerns	O
of	O
some	O
engineers	O
,	O
SMCS-NG	O
was	O
created	O
as	O
a	O
port	O
to	O
Microsoft	B-Application
Windows	I-Application
of	O
the	O
SMCS	B-General_Concept
infrastructure	O
and	O
applications	O
,	O
a	O
move	O
which	O
some	O
commentators	O
have	O
termed	O
"	O
Windows	O
for	O
Warships	O
"	O
.	O
</s>
<s>
The	O
UK	O
's	O
Defence	O
Ministry	O
later	O
gave	O
assurances	O
,	O
through	O
questions	O
in	O
the	O
UK	O
parliament	O
,	O
that	O
this	O
is	O
a	O
low	O
risk	O
use	O
of	O
Microsoft	B-Application
Windows	I-Application
.	O
</s>
<s>
The	O
consoles	O
for	O
the	O
new	O
Sonar	O
2076	O
supplied	O
by	O
Thales	O
Underwater	O
Systems	O
for	O
the	O
Astute	O
class	O
submarines	O
,	O
and	O
which	O
may	O
be	O
retro-fitted	O
to	O
other	O
classes	O
,	O
are	O
built	O
as	O
PCs	O
running	O
Linux	B-Application
rather	O
than	O
Windows	O
.	O
</s>
<s>
Having	O
developed	O
SMCS-NG	O
as	O
an	O
internal	O
project	O
,	O
BAE	O
Systems	O
independently	O
proposed	O
to	O
the	O
MoD	O
that	O
the	O
original	O
SMCS	B-General_Concept
equipment	O
be	O
replaced	O
by	O
its	O
own	O
,	O
newer	O
,	O
version	O
.	O
</s>
<s>
After	O
sea	O
trials	O
in	O
,	O
the	O
MoD	O
awarded	O
contracts	O
to	O
BAE	O
Systems	O
for	O
refit	O
of	O
SMCS-NG	O
into	O
most	O
RN	O
submarines	O
,	O
including	O
the	O
Vanguard	O
fleet	O
.	O
</s>
<s>
Although	O
the	O
Defence	O
Minister	O
Adam	O
Ingram	O
told	O
the	O
UK	O
Parliament	O
in	O
October	O
2004	O
that	O
no	O
decision	O
had	O
been	O
made	O
about	O
conversion	O
of	O
the	O
Vanguard	O
fleet	O
to	O
run	O
SMCS-NG	O
,	O
the	O
MoD	O
placed	O
the	O
contracts	O
the	O
following	O
month	O
.	O
</s>
<s>
By	O
December	O
2008	O
,	O
all	O
of	O
the	O
active	O
Royal	O
Navy	O
submarines	O
had	O
been	O
retrofitted	O
with	O
SMCS-NG	O
.	O
</s>
<s>
Unlike	O
with	O
previous	O
versions	O
of	O
SMCS	B-General_Concept
,	O
the	O
software	O
is	O
supplied	O
as	O
a	O
single-fit	O
release	O
which	O
is	O
intended	O
to	O
be	O
configured	O
for	O
the	O
sensor	O
and	O
weapon	O
fit	O
of	O
each	O
submarine	O
.	O
</s>
