<s>
The	O
Launch	B-Device
Vehicle	I-Device
Digital	I-Device
Computer	I-Device
(	O
LVDC	B-Device
)	O
was	O
a	O
computer	O
that	O
provided	O
the	O
autopilot	O
for	O
the	O
Saturn	O
V	O
rocket	O
from	O
launch	O
to	O
Earth	O
orbit	O
insertion	O
.	O
</s>
<s>
The	O
LVDC	B-Device
also	O
supported	O
pre	O
-	O
and	O
post-launch	O
checkout	O
of	O
the	O
Saturn	O
hardware	O
.	O
</s>
<s>
The	O
LVDC	B-Device
was	O
capable	O
of	O
executing	O
12190	O
instructions	O
per	O
second	O
.	O
</s>
<s>
For	O
reliability	O
,	O
the	O
LVDC	B-Device
used	O
triple-redundant	B-Error_Name
logic	I-Error_Name
and	O
a	O
voting	O
system	O
.	O
</s>
<s>
Each	O
logic	O
system	O
was	O
split	O
into	O
a	O
seven-stage	O
pipeline	B-General_Concept
.	O
</s>
<s>
At	O
each	O
stage	O
in	O
the	O
pipeline	B-General_Concept
,	O
a	O
voting	O
system	O
would	O
take	O
a	O
majority	O
vote	O
on	O
the	O
results	O
,	O
with	O
the	O
most	O
popular	O
result	O
being	O
passed	O
on	O
to	O
the	O
next	O
stage	O
in	O
all	O
pipelines	B-General_Concept
.	O
</s>
<s>
This	O
meant	O
that	O
,	O
for	O
each	O
of	O
the	O
seven	O
stages	O
,	O
one	O
module	O
in	O
any	O
one	O
of	O
the	O
three	O
pipelines	B-General_Concept
could	O
fail	O
,	O
and	O
the	O
LVDC	B-Device
would	O
still	O
produce	O
the	O
correct	O
results	O
.	O
</s>
<s>
The	O
LVDC	B-Device
communicated	O
digitally	O
with	O
a	O
Launch	O
Vehicle	O
Data	O
adapter	O
(	O
LVDA	O
)	O
.	O
</s>
<s>
LVDC	B-Device
instruction	O
words	O
were	O
split	O
into	O
a	O
4-bit	O
opcode	O
field	O
(	O
least-significant	O
bits	O
)	O
and	O
a	O
9-bit	O
operand	O
address	O
field	O
(	O
most-significant	O
bits	O
)	O
.	O
</s>
<s>
The	O
eighteen	O
possible	O
LVDC	B-Device
instructions	O
were	O
:	O
</s>
<s>
In	O
flight	O
the	O
LVDC	B-Device
ran	O
a	O
major	O
computation	O
loop	O
every	O
2	O
seconds	O
for	O
vehicle	O
guidance	O
,	O
and	O
a	O
minor	O
loop	O
25	O
times	O
a	O
second	O
for	O
attitude	O
control	O
.	O
</s>
<s>
Unlike	O
the	O
Apollo	B-Application
Guidance	I-Application
Computer	I-Application
software	O
,	O
the	O
software	O
which	O
ran	O
on	O
the	O
LVDC	B-Device
seems	O
to	O
have	O
vanished	O
.	O
</s>
<s>
While	O
the	O
hardware	O
would	O
be	O
fairly	O
simple	O
to	O
emulate	O
,	O
the	O
only	O
remaining	O
copies	O
of	O
the	O
software	O
are	O
probably	O
in	O
the	O
core	O
memory	O
of	O
the	O
Instrument	O
Unit	O
LVDCs	B-Device
of	O
the	O
remaining	O
Saturn	O
V	O
rockets	O
on	O
display	O
at	O
NASA	O
sites	O
.	O
</s>
<s>
The	O
LVDC	B-Device
could	O
also	O
respond	O
to	O
a	O
number	O
of	O
interrupts	O
triggered	O
by	O
external	O
events	O
.	O
</s>
<s>
The	O
LVDC	B-Device
was	O
approximately	O
wide	O
,	O
high	O
,	O
and	O
deep	O
and	O
weighed	O
.	O
</s>
<s>
The	O
decision	O
to	O
cool	O
the	O
LVDC	B-Device
by	O
circulating	O
coolant	O
through	O
the	O
walls	O
of	O
the	O
computer	O
was	O
unique	O
at	O
the	O
time	O
and	O
allowed	O
the	O
LVDC	B-Device
and	O
LVDA	O
(	O
part-cooled	O
using	O
this	O
technique	O
)	O
to	O
be	O
placed	O
in	O
one	O
cold	O
plate	O
location	O
due	O
to	O
the	O
three	O
dimensional	O
packaging	O
.	O
</s>
<s>
The	O
alloy	O
LA	O
141	O
had	O
been	O
used	O
by	O
IBM	O
on	O
the	O
Gemini	O
keyboard	O
,	O
read	O
out	O
units	O
,	O
and	O
computer	O
in	O
small	O
quantities	O
and	O
the	O
larger	O
frame	O
of	O
the	O
LVDC	B-Device
was	O
produced	O
from	O
the	O
largest	O
billets	O
of	O
LA	O
141	O
cast	O
at	O
the	O
time	O
and	O
subsequently	O
CNC	O
machined	O
into	O
the	O
frame	O
.	O
</s>
<s>
The	O
unit	O
logic	O
device	O
(	O
ULD	O
)	O
was	O
a	O
smaller	O
version	O
of	O
IBM	O
's	O
Solid	B-Algorithm
Logic	I-Algorithm
Technology	I-Algorithm
(	O
SLT	O
)	O
module	O
,	O
but	O
with	O
clip	O
connections	O
.	O
</s>
