<s>
The	O
ORDVAC	B-Device
(	O
Ordnance	O
Discrete	O
Variable	O
Automatic	O
Computer	O
)	O
,	O
is	O
an	O
early	O
computer	O
built	O
by	O
the	O
University	O
of	O
Illinois	O
for	O
the	O
Ballistic	O
Research	O
Laboratory	O
at	O
Aberdeen	O
Proving	O
Ground	O
.	O
</s>
<s>
A	O
successor	O
to	O
the	O
ENIAC	B-Device
(	O
along	O
with	O
EDVAC	B-Device
built	O
earlier	O
)	O
.	O
</s>
<s>
It	O
was	O
based	O
on	O
the	O
IAS	B-Device
architecture	O
developed	O
by	O
John	O
von	O
Neumann	O
,	O
which	O
came	O
to	O
be	O
known	O
as	O
the	O
von	B-Architecture
Neumann	I-Architecture
architecture	I-Architecture
.	O
</s>
<s>
The	O
ORDVAC	B-Device
was	O
the	O
first	B-Architecture
computer	I-Architecture
to	O
have	O
a	O
compiler	B-Language
.	O
</s>
<s>
ORDVAC	B-Device
passed	O
its	O
acceptance	O
tests	O
on	O
March	O
6	O
,	O
1952	O
,	O
at	O
Aberdeen	O
Proving	O
Ground	O
in	O
Maryland	O
.	O
</s>
<s>
Unlike	O
the	O
other	O
computers	O
of	O
its	O
era	O
,	O
the	O
ORDVAC	B-Device
and	O
ILLIAC	B-Device
I	I-Device
were	O
twins	O
and	O
could	O
exchange	O
programs	O
with	O
each	O
other	O
.	O
</s>
<s>
The	O
later	O
SILLIAC	B-Device
computer	O
was	O
a	O
copy	O
of	O
the	O
ORDVAC/ILLIAC	O
series	O
.	O
</s>
<s>
J	O
.	O
P	O
.	O
Nash	O
of	O
the	O
University	O
of	O
Illinois	O
was	O
a	O
developer	O
of	O
both	O
the	O
ORDVAC	B-Device
and	O
of	O
the	O
university	O
's	O
own	O
identical	O
copy	O
,	O
the	O
ILLIAC	B-Device
,	O
which	O
was	O
later	O
renamed	O
the	O
ILLIAC	B-Device
I	I-Device
.	O
Abe	O
Taub	O
,	O
Sylvian	O
Ray	O
,	O
and	O
Donald	O
B	O
.	O
Gillies	O
assisted	O
in	O
the	O
checkout	O
of	O
ORDVAC	B-Device
at	O
Aberdeen	O
Proving	O
Ground	O
.	O
</s>
<s>
After	O
ORDVAC	B-Device
was	O
moved	O
to	O
Aberdeen	O
,	O
it	O
was	O
used	O
remotely	O
by	O
telephone	O
by	O
the	O
University	O
of	O
Illinois	O
for	O
up	O
to	O
eight	O
hours	O
per	O
night	O
.	O
</s>
<s>
It	O
was	O
one	O
of	O
the	O
first	B-Architecture
computers	I-Architecture
to	O
be	O
used	O
remotely	O
and	O
probably	O
the	O
first	O
to	O
routinely	O
be	O
used	O
remotely	O
.	O
</s>
<s>
The	O
ORDVAC	B-Device
used	O
2178	O
vacuum	O
tubes	O
.	O
</s>
<s>
Its	O
main	O
memory	O
consisted	O
of	O
1024	O
words	O
of	O
40	O
bits	O
each	O
,	O
stored	O
using	O
Williams	B-General_Concept
tubes	I-General_Concept
.	O
</s>
<s>
It	O
was	O
a	O
rare	O
asynchronous	B-Application
machine	O
,	O
meaning	O
that	O
there	O
was	O
no	O
central	O
clock	O
regulating	O
the	O
timing	O
of	O
the	O
instructions	O
.	O
</s>
<s>
Among	O
the	O
ORDVAC	B-Device
programmers	O
were	O
Martin	O
Davis	O
and	O
Elsie	O
Shutt	O
.	O
</s>
<s>
ORDVAC	B-Device
and	O
its	O
successor	O
at	O
Aberdeen	O
Proving	O
Ground	O
,	O
BRLESC	B-Device
,	O
used	O
their	O
own	O
unique	O
notation	O
for	O
hexadecimal	O
numbers	O
.	O
</s>
<s>
When	O
ORDVAC	B-Device
was	O
completed	O
,	O
it	O
was	O
tested	O
at	O
the	O
University	O
of	O
Illinois	O
and	O
then	O
disassembled	O
and	O
shipped	O
to	O
Aberdeen	O
Proving	O
Ground	O
in	O
Maryland	O
.	O
</s>
<s>
When	O
some	O
military	O
officers	O
came	O
to	O
check	O
on	O
the	O
progress	O
of	O
Ordvac	B-Device
assembly	O
,	O
they	O
asked	O
,	O
"	O
Who	O
is	O
in	O
charge	O
here	O
?	O
</s>
