<s>
ENIAC	B-Device
(	O
;	O
Electronic	B-Device
Numerical	I-Device
Integrator	I-Device
and	I-Device
Computer	I-Device
)	O
was	O
the	O
first	O
programmable	B-General_Concept
,	O
electronic	O
,	O
general-purpose	O
digital	O
computer	O
,	O
completed	O
in	O
1945	O
.	O
</s>
<s>
There	O
were	O
other	O
computers	O
that	O
had	O
combinations	O
of	O
these	O
features	O
,	O
but	O
the	O
ENIAC	B-Device
had	O
all	O
of	O
them	O
in	O
one	O
package	O
.	O
</s>
<s>
Although	O
ENIAC	B-Device
was	O
designed	O
and	O
primarily	O
used	O
to	O
calculate	O
artillery	B-Application
firing	O
tables	O
for	O
the	O
United	O
States	O
Army	O
's	O
Ballistic	O
Research	O
Laboratory	O
(	O
which	O
later	O
became	O
a	O
part	O
of	O
the	O
Army	O
Research	O
Laboratory	O
)	O
,	O
its	O
first	O
program	O
was	O
a	O
study	O
of	O
the	O
feasibility	O
of	O
the	O
thermonuclear	O
weapon	O
.	O
</s>
<s>
ENIAC	B-Device
was	O
completed	O
in	O
1945	O
and	O
first	O
put	O
to	O
work	O
for	O
practical	O
purposes	O
on	O
December	O
10	O
,	O
1945	O
.	O
</s>
<s>
ENIAC	B-Device
was	O
formally	O
dedicated	O
at	O
the	O
University	O
of	O
Pennsylvania	O
on	O
February	O
15	O
,	O
1946	O
,	O
having	O
cost	O
$	O
487,000	O
(	O
)	O
,	O
and	O
called	O
a	O
"	O
Giant	O
Brain	O
"	O
by	O
the	O
press	O
.	O
</s>
<s>
ENIAC	B-Device
was	O
formally	O
accepted	O
by	O
the	O
U.S.	O
Army	O
Ordnance	O
Corps	O
in	O
July	O
1946	O
.	O
</s>
<s>
ENIAC	B-Device
's	O
design	O
and	O
construction	O
was	O
financed	O
by	O
the	O
United	O
States	O
Army	O
,	O
Ordnance	O
Corps	O
,	O
Research	O
and	O
Development	O
Command	O
,	O
led	O
by	O
Major	O
General	O
Gladeon	O
M	O
.	O
Barnes	O
.	O
</s>
<s>
The	O
construction	O
contract	O
was	O
signed	O
on	O
June	O
5	O
,	O
1943	O
;	O
work	O
on	O
the	O
computer	O
began	O
in	O
secret	O
at	O
the	O
University	O
of	O
Pennsylvania	O
's	O
Moore	O
School	O
of	O
Electrical	O
Engineering	O
the	O
following	O
month	O
,	O
under	O
the	O
code	O
name	O
"	O
Project	B-Device
PX	I-Device
"	O
,	O
with	O
John	O
Grist	O
Brainerd	O
as	O
principal	O
investigator	O
.	O
</s>
<s>
ENIAC	B-Device
was	O
designed	O
by	O
Ursinus	O
College	O
physics	O
professor	O
John	O
Mauchly	O
and	O
J	O
.	O
Presper	O
Eckert	O
of	O
the	O
University	O
of	O
Pennsylvania	O
,	O
U.S.	O
</s>
<s>
The	O
team	O
of	O
design	O
engineers	O
assisting	O
the	O
development	O
included	O
Robert	O
F	O
.	O
Shaw	O
(	O
function	O
tables	O
)	O
,	O
Jeffrey	O
Chuan	O
Chu	O
(	O
divider/square	O
-rooter	O
)	O
,	O
Thomas	O
Kite	O
Sharpless	O
(	O
master	O
programmer	O
)	O
,	O
Frank	O
Mural	O
(	O
master	O
programmer	O
)	O
,	O
Arthur	O
Burks	O
(	O
multiplier	O
)	O
,	O
Harry	O
Huskey	O
(	O
reader/printer	O
)	O
and	O
Jack	O
Davis	O
(	O
accumulators	B-General_Concept
)	O
.	O
</s>
<s>
Significant	O
development	O
work	O
was	O
undertaken	O
by	O
the	O
female	O
mathematicians	O
who	O
handled	O
the	O
bulk	O
of	O
the	O
ENIAC	B-Device
programming	O
:	O
Jean	O
Jennings	O
,	O
Marlyn	O
Wescoff	O
,	O
Ruth	O
Lichterman	O
,	O
Betty	O
Snyder	O
,	O
Frances	O
Bilas	O
,	O
and	O
Kay	O
McNulty	O
.	O
</s>
<s>
ENIAC	B-Device
was	O
a	O
large	O
,	O
modular	O
computer	O
,	O
composed	O
of	O
individual	O
panels	O
to	O
perform	O
different	O
functions	O
.	O
</s>
<s>
Twenty	O
of	O
these	O
modules	O
were	O
accumulators	B-General_Concept
that	O
could	O
not	O
only	O
add	O
and	O
subtract	O
,	O
but	O
hold	O
a	O
ten-digit	O
decimal	B-Application
number	O
in	O
memory	O
.	O
</s>
<s>
Numbers	O
were	O
passed	O
between	O
these	O
units	O
across	O
several	O
general-purpose	O
buses	B-General_Concept
(	O
or	O
trays	O
,	O
as	O
they	O
were	O
called	O
)	O
.	O
</s>
<s>
By	O
the	O
end	O
of	O
its	O
operation	O
in	O
1956	O
,	O
ENIAC	B-Device
contained	O
18,000	O
vacuum	O
tubes	O
,	O
7,200	O
crystal	O
diodes	O
,	O
1,500	O
relays	O
,	O
70,000	O
resistors	O
,	O
10,000	O
capacitors	O
,	O
and	O
approximately	O
5,000,000	O
hand-soldered	O
joints	O
.	O
</s>
<s>
Input	O
was	O
possible	O
from	O
an	O
IBM	O
card	B-Device
reader	I-Device
and	O
an	O
IBM	O
card	B-Device
punch	I-Device
was	O
used	O
for	O
output	O
.	O
</s>
<s>
While	O
ENIAC	B-Device
had	O
no	O
system	O
to	O
store	O
memory	O
in	O
its	O
inception	O
,	O
these	O
punch	B-Device
cards	O
could	O
be	O
used	O
for	O
external	O
memory	O
storage	O
.	O
</s>
<s>
In	O
1953	O
,	O
a	O
100-word	O
magnetic-core	O
memory	O
built	O
by	O
the	O
Burroughs	O
Corporation	O
was	O
added	O
to	O
ENIAC	B-Device
.	O
</s>
<s>
ENIAC	B-Device
used	O
ten-position	B-Algorithm
ring	B-General_Concept
counters	I-General_Concept
to	O
store	O
digits	O
;	O
each	O
digit	O
required	O
36	O
vacuum	O
tubes	O
,	O
10	O
of	O
which	O
were	O
the	O
dual	O
triodes	O
making	O
up	O
the	O
flip-flops	B-General_Concept
of	O
the	O
ring	B-General_Concept
counter	I-General_Concept
.	O
</s>
<s>
Arithmetic	O
was	O
performed	O
by	O
"	O
counting	O
"	O
pulses	O
with	O
the	O
ring	B-General_Concept
counters	I-General_Concept
and	O
generating	O
carry	O
pulses	O
if	O
the	O
counter	O
"	O
wrapped	O
around	O
"	O
,	O
the	O
idea	O
being	O
to	O
electronically	O
emulate	O
the	O
operation	O
of	O
the	O
digit	O
wheels	O
of	O
a	O
mechanical	O
adding	O
machine	O
.	O
</s>
<s>
ENIAC	B-Device
had	O
20	O
ten-digit	O
signed	O
accumulators	B-General_Concept
,	O
which	O
used	O
ten	B-Algorithm
's	I-Algorithm
complement	I-Algorithm
representation	O
and	O
could	O
perform	O
5,000	O
simple	O
addition	O
or	O
subtraction	O
operations	O
between	O
any	O
of	O
them	O
and	O
a	O
source	O
(	O
e.g.	O
,	O
another	O
accumulator	B-General_Concept
or	O
a	O
constant	O
transmitter	O
)	O
per	O
second	O
.	O
</s>
<s>
It	O
was	O
possible	O
to	O
connect	O
several	O
accumulators	B-General_Concept
to	O
run	O
simultaneously	O
,	O
so	O
the	O
peak	O
speed	O
of	O
operation	O
was	O
potentially	O
much	O
higher	O
,	O
due	O
to	O
parallel	O
operation	O
.	O
</s>
<s>
It	O
was	O
possible	O
to	O
wire	O
the	O
carry	O
of	O
one	O
accumulator	B-General_Concept
into	O
another	O
accumulator	B-General_Concept
to	O
perform	O
arithmetic	O
with	O
double	O
the	O
precision	O
,	O
but	O
the	O
accumulator	B-General_Concept
carry	O
circuit	O
timing	O
prevented	O
the	O
wiring	O
of	O
three	O
or	O
more	O
for	O
even	O
higher	O
precision	O
.	O
</s>
<s>
ENIAC	B-Device
used	O
four	O
of	O
the	O
accumulators	B-General_Concept
(	O
controlled	O
by	O
a	O
special	O
multiplier	O
unit	O
)	O
to	O
perform	O
up	O
to	O
385	O
multiplication	O
operations	O
per	O
second	O
;	O
five	O
of	O
the	O
accumulators	B-General_Concept
were	O
controlled	O
by	O
a	O
special	O
divider/square	O
-rooter	O
unit	O
to	O
perform	O
up	O
to	O
40	O
division	O
operations	O
per	O
second	O
or	O
three	O
square	O
root	O
operations	O
per	O
second	O
.	O
</s>
<s>
The	O
other	O
nine	O
units	O
in	O
ENIAC	B-Device
were	O
the	O
initiating	O
unit	O
(	O
started	O
and	O
stopped	O
the	O
machine	O
)	O
,	O
the	O
cycling	O
unit	O
(	O
used	O
for	O
synchronizing	O
the	O
other	O
units	O
)	O
,	O
the	O
master	O
programmer	O
(	O
controlled	O
loop	O
sequencing	O
)	O
,	O
the	O
reader	O
(	O
controlled	O
an	O
IBM	O
punch-card	O
reader	O
)	O
,	O
the	O
printer	O
(	O
controlled	O
an	O
IBM	O
card	B-Device
punch	I-Device
)	O
,	O
the	O
constant	O
transmitter	O
,	O
and	O
three	O
function	O
tables	O
.	O
</s>
<s>
In	O
one	O
of	O
these	O
cycles	O
,	O
ENIAC	B-Device
could	O
write	O
a	O
number	O
to	O
a	O
register	O
,	O
read	O
a	O
number	O
from	O
a	O
register	O
,	O
or	O
add/subtract	O
two	O
numbers	O
.	O
</s>
<s>
ENIAC	B-Device
is	O
able	O
to	O
process	O
about	O
500	O
FLOPS	O
,	O
compared	O
to	O
modern	O
supercomputers	O
 '	O
petascale	B-General_Concept
and	O
exascale	B-General_Concept
computing	I-General_Concept
power	O
.	O
</s>
<s>
ENIAC	B-Device
used	O
common	O
octal-base	O
radio	O
tubes	O
of	O
the	O
day	O
;	O
the	O
decimal	B-Application
accumulators	B-General_Concept
were	O
made	O
of	O
6SN7	O
flip-flops	B-General_Concept
,	O
while	O
6L7s	O
,	O
6SJ7s	O
,	O
6SA7s	O
and	O
6AC7s	O
were	O
used	O
in	O
logic	O
functions	O
.	O
</s>
<s>
Several	O
tubes	O
burned	O
out	O
almost	O
every	O
day	O
,	O
leaving	O
ENIAC	B-Device
nonfunctional	O
about	O
half	O
the	O
time	O
.	O
</s>
<s>
Engineers	O
reduced	O
ENIAC	B-Device
's	O
tube	O
failures	O
to	O
the	O
more	O
acceptable	O
rate	O
of	O
one	O
tube	O
every	O
two	O
days	O
.	O
</s>
<s>
ENIAC	B-Device
could	O
be	O
programmed	O
to	O
perform	O
complex	O
sequences	O
of	O
operations	O
,	O
including	O
loops	O
,	O
branches	O
,	O
and	O
subroutines	O
.	O
</s>
<s>
However	O
,	O
instead	O
of	O
the	O
stored-program	O
computers	O
that	O
exist	O
today	O
,	O
ENIAC	B-Device
was	O
just	O
a	O
large	O
collection	O
of	O
arithmetic	O
machines	O
,	O
which	O
originally	O
had	O
programs	O
set	O
up	O
into	O
the	O
machine	O
by	O
a	O
combination	O
of	O
plugboard	O
wiring	O
and	O
three	O
portable	O
function	O
tables	O
(	O
containing	O
1,200	O
ten-way	O
switches	O
each	O
)	O
.	O
</s>
<s>
After	O
the	O
program	O
was	O
figured	O
out	O
on	O
paper	O
,	O
the	O
process	O
of	O
getting	O
the	O
program	O
into	O
ENIAC	B-Device
by	O
manipulating	O
its	O
switches	O
and	O
cables	O
could	O
take	O
days	O
.	O
</s>
<s>
A	O
programming	O
tutorial	O
for	O
the	O
modulo	O
function	O
using	O
an	O
ENIAC	B-Device
simulator	O
gives	O
an	O
impression	O
of	O
what	O
a	O
program	O
on	O
the	O
ENIAC	B-Device
looked	O
like	O
.	O
</s>
<s>
ENIAC	B-Device
's	O
six	O
primary	O
programmers	O
,	O
Kay	O
McNulty	O
,	O
Betty	O
Jennings	O
,	O
Betty	O
Snyder	O
,	O
Marlyn	O
Wescoff	O
,	O
Fran	O
Bilas	O
and	O
Ruth	O
Lichterman	O
,	O
not	O
only	O
determined	O
how	O
to	O
input	O
ENIAC	B-Device
programs	O
,	O
but	O
also	O
developed	O
an	O
understanding	O
of	O
ENIAC	B-Device
's	O
inner	O
workings	O
.	O
</s>
<s>
Kay	O
McNulty	O
,	O
Betty	O
Jennings	O
,	O
Betty	O
Snyder	O
,	O
Marlyn	O
Meltzer	O
,	O
Fran	O
Bilas	O
,	O
and	O
Ruth	O
Lichterman	O
were	O
the	O
first	O
programmers	O
of	O
the	O
ENIAC	B-Device
.	O
</s>
<s>
Nevertheless	O
,	O
some	O
of	O
the	O
women	O
did	O
not	O
receive	O
recognition	O
for	O
their	O
work	O
on	O
the	O
ENIAC	B-Device
in	O
their	O
lifetimes	O
.	O
</s>
<s>
After	O
the	O
war	O
ended	O
,	O
the	O
women	O
continued	O
to	O
work	O
on	O
the	O
ENIAC	B-Device
.	O
</s>
<s>
Betty	O
Holberton	O
(	O
née	O
Snyder	O
)	O
continued	O
on	O
to	O
help	O
write	O
the	O
first	O
generative	O
programming	O
system	O
(	O
SORT/MERGE	B-Application
)	O
and	O
help	O
design	O
the	O
first	O
commercial	O
electronic	O
computers	O
,	O
the	O
UNIVAC	O
and	O
the	O
BINAC	B-Device
,	O
alongside	O
Jean	O
Jennings	O
.	O
</s>
<s>
McNulty	O
developed	O
the	O
use	O
of	O
subroutines	O
in	O
order	O
to	O
help	O
increase	O
ENIAC	B-Device
's	O
computational	O
capability	O
.	O
</s>
<s>
Herman	O
Goldstine	O
selected	O
the	O
programmers	O
,	O
whom	O
he	O
called	O
operators	O
,	O
from	O
the	O
computers	O
who	O
had	O
been	O
calculating	O
ballistics	O
tables	O
with	O
mechanical	O
desk	O
calculators	O
,	O
and	O
a	O
differential	O
analyzer	O
prior	O
to	O
and	O
during	O
the	O
development	O
of	O
ENIAC	B-Device
.	O
</s>
<s>
Under	O
Herman	O
and	O
Adele	O
Goldstine	O
's	O
direction	O
,	O
the	O
computers	O
studied	O
ENIAC	B-Device
's	O
blueprints	O
and	O
physical	O
structure	O
to	O
determine	O
how	O
to	O
manipulate	O
its	O
switches	O
and	O
cables	O
,	O
as	O
programming	O
languages	O
did	O
not	O
yet	O
exist	O
.	O
</s>
<s>
Though	O
contemporaries	O
considered	O
programming	O
a	O
clerical	O
task	O
and	O
did	O
not	O
publicly	O
recognize	O
the	O
programmers	O
 '	O
effect	O
on	O
the	O
successful	O
operation	O
and	O
announcement	O
of	O
ENIAC	B-Device
,	O
McNulty	O
,	O
Jennings	O
,	O
Snyder	O
,	O
Wescoff	O
,	O
Bilas	O
,	O
and	O
Lichterman	O
have	O
since	O
been	O
recognized	O
for	O
their	O
contributions	O
to	O
computing	O
.	O
</s>
<s>
Following	O
the	O
initial	O
six	O
programmers	O
,	O
an	O
expanded	O
team	O
of	O
a	O
hundred	O
scientists	O
was	O
recruited	O
to	O
continue	O
work	O
on	O
the	O
ENIAC	B-Device
.	O
</s>
<s>
Adele	O
Goldstine	O
wrote	O
the	O
original	O
technical	O
description	O
of	O
the	O
ENIAC	B-Device
.	O
</s>
<s>
Several	O
language	O
systems	O
were	O
developed	O
to	O
describe	O
programs	O
for	O
the	O
ENIAC	B-Device
,	O
including	O
:	O
</s>
<s>
Year	O
Name	O
Chief	O
developers	O
1943	O
–	O
46	O
ENIAC	B-Device
coding	O
system	O
John	O
von	O
Neumann	O
,	O
John	O
Mauchly	O
,	O
J	O
.	O
Presper	O
Eckert	O
,	O
Herman	O
Goldstine	O
after	O
Alan	O
Turing	O
.	O
</s>
<s>
Although	O
the	O
Ballistic	O
Research	O
Laboratory	O
was	O
the	O
sponsor	O
of	O
ENIAC	B-Device
,	O
one	O
year	O
into	O
this	O
three-year	O
project	O
John	O
von	O
Neumann	O
,	O
a	O
mathematician	O
working	O
on	O
the	O
hydrogen	O
bomb	O
at	O
Los	O
Alamos	O
National	O
Laboratory	O
,	O
became	O
aware	O
of	O
this	O
computer	O
.	O
</s>
<s>
Los	O
Alamos	O
subsequently	O
became	O
so	O
involved	O
with	O
ENIAC	B-Device
that	O
the	O
first	O
test	O
problem	O
run	O
consisted	O
of	O
computations	O
for	O
the	O
hydrogen	O
bomb	O
,	O
not	O
artillery	B-Application
tables	O
.	O
</s>
<s>
Related	O
to	O
ENIAC	B-Device
's	O
role	O
in	O
the	O
hydrogen	O
bomb	O
was	O
its	O
role	O
in	O
the	O
Monte	B-Algorithm
Carlo	I-Algorithm
method	I-Algorithm
becoming	O
popular	O
.	O
</s>
<s>
John	O
von	O
Neumann	O
and	O
Stanislaw	O
Ulam	O
realized	O
the	O
speed	O
of	O
ENIAC	B-Device
would	O
allow	O
these	O
calculations	O
to	O
be	O
done	O
much	O
more	O
quickly	O
.	O
</s>
<s>
The	O
success	O
of	O
this	O
project	O
showed	O
the	O
value	O
of	O
Monte	B-Algorithm
Carlo	I-Algorithm
methods	I-Algorithm
in	O
science	O
.	O
</s>
<s>
ENIAC	B-Device
was	O
shut	O
down	O
on	O
November	O
9	O
,	O
1946	O
,	O
for	O
a	O
refurbishment	O
and	O
a	O
memory	O
upgrade	O
,	O
and	O
was	O
transferred	O
to	O
Aberdeen	O
Proving	O
Ground	O
,	O
Maryland	O
in	O
1947	O
.	O
</s>
<s>
A	O
few	O
months	O
after	O
ENIAC	B-Device
's	O
unveiling	O
in	O
the	O
summer	O
of	O
1946	O
,	O
as	O
part	O
of	O
"	O
an	O
extraordinary	O
effort	O
to	O
jump-start	O
research	O
in	O
the	O
field	O
"	O
,	O
the	O
Pentagon	O
invited	O
"	O
the	O
top	O
people	O
in	O
electronics	O
and	O
mathematics	O
from	O
the	O
United	O
States	O
and	O
Great	O
Britain	O
"	O
to	O
a	O
series	O
of	O
forty-eight	O
lectures	O
given	O
in	O
Philadelphia	O
,	O
Pennsylvania	O
;	O
all	O
together	O
called	O
The	O
Theory	O
and	O
Techniques	O
for	O
Design	O
of	O
Digital	O
Computers	O
—	O
more	O
often	O
named	O
the	O
Moore	O
School	O
Lectures	O
.	O
</s>
<s>
Half	O
of	O
these	O
lectures	O
were	O
given	O
by	O
the	O
inventors	O
of	O
ENIAC	B-Device
.	O
</s>
<s>
ENIAC	B-Device
was	O
a	O
one-of-a-kind	O
design	O
and	O
was	O
never	O
repeated	O
.	O
</s>
<s>
Eckert	O
and	O
Mauchly	O
started	O
work	O
on	O
a	O
new	O
design	O
,	O
to	O
be	O
later	O
called	O
the	O
EDVAC	B-Device
,	O
which	O
would	O
be	O
both	O
simpler	O
and	O
more	O
powerful	O
.	O
</s>
<s>
John	O
von	O
Neumann	O
,	O
who	O
was	O
consulting	O
for	O
the	O
Moore	O
School	O
on	O
the	O
EDVAC	B-Device
,	O
sat	O
in	O
on	O
the	O
Moore	O
School	O
meetings	O
at	O
which	O
the	O
stored	O
program	O
concept	O
was	O
elaborated	O
.	O
</s>
<s>
Von	O
Neumann	O
wrote	O
up	O
an	O
incomplete	O
set	O
of	O
notes	O
(	O
First	O
Draft	O
of	O
a	O
Report	O
on	O
the	O
EDVAC	B-Device
)	O
which	O
were	O
intended	O
to	O
be	O
used	O
as	O
an	O
internal	O
memorandum	O
—	O
describing	O
,	O
elaborating	O
,	O
and	O
couching	O
in	O
formal	O
logical	O
language	O
the	O
ideas	O
developed	O
in	O
the	O
meetings	O
.	O
</s>
<s>
ENIAC	B-Device
administrator	O
and	O
security	O
officer	O
Herman	O
Goldstine	O
distributed	O
copies	O
of	O
this	O
First	O
Draft	O
to	O
a	O
number	O
of	O
government	O
and	O
educational	O
institutions	O
,	O
spurring	O
widespread	O
interest	O
in	O
the	O
construction	O
of	O
a	O
new	O
generation	O
of	O
electronic	O
computing	O
machines	O
,	O
including	O
Electronic	B-Device
Delay	I-Device
Storage	I-Device
Automatic	I-Device
Calculator	I-Device
(	O
EDSAC	B-Device
)	O
at	O
Cambridge	O
University	O
,	O
England	O
and	O
SEAC	B-Device
at	O
the	O
U.S.	O
Bureau	O
of	O
Standards	O
.	O
</s>
<s>
A	O
number	O
of	O
improvements	O
were	O
made	O
to	O
ENIAC	B-Device
after	O
1947	O
,	O
including	O
a	O
primitive	O
read-only	O
stored	O
programming	O
mechanism	O
using	O
the	O
function	O
tables	O
as	O
program	O
ROM	B-Device
,	O
after	O
which	O
programming	O
was	O
done	O
by	O
setting	O
the	O
switches	O
.	O
</s>
<s>
The	O
idea	O
has	O
been	O
worked	O
out	O
in	O
several	O
variants	O
by	O
Richard	O
Clippinger	O
and	O
his	O
group	O
,	O
on	O
the	O
one	O
hand	O
,	O
and	O
the	O
Goldstines	O
,	O
on	O
the	O
other	O
,	O
and	O
it	O
was	O
included	O
in	O
the	O
ENIAC	B-Device
patent	O
.	O
</s>
<s>
Three	O
digits	O
of	O
one	O
accumulator	B-General_Concept
(	O
#6	O
)	O
were	O
used	O
as	O
the	O
program	O
counter	O
,	O
another	O
accumulator	B-General_Concept
(	O
#15	O
)	O
was	O
used	O
as	O
the	O
main	O
accumulator	B-General_Concept
,	O
a	O
third	O
accumulator	B-General_Concept
(	O
#8	O
)	O
was	O
used	O
as	O
the	O
address	O
pointer	O
for	O
reading	O
data	O
from	O
the	O
function	O
tables	O
,	O
and	O
most	O
of	O
the	O
other	O
accumulators	B-General_Concept
(	O
1	O
–	O
5	O
,	O
7	O
,	O
9	O
–	O
14	O
,	O
17	O
–	O
19	O
)	O
were	O
used	O
for	O
data	O
memory	O
.	O
</s>
<s>
The	O
"	O
first	O
production	O
run	O
"	O
of	O
the	O
new	O
coding	O
techniques	O
on	O
the	O
Monte	B-Algorithm
Carlo	I-Algorithm
problem	O
followed	O
in	O
April	O
.	O
</s>
<s>
After	O
ENIAC	B-Device
's	O
move	O
to	O
Aberdeen	O
,	O
a	O
register	O
panel	O
for	O
memory	O
was	O
also	O
constructed	O
,	O
but	O
it	O
did	O
not	O
work	O
.	O
</s>
<s>
The	O
programming	O
of	O
the	O
stored	O
program	O
for	O
ENIAC	B-Device
was	O
done	O
by	O
Betty	O
Jennings	O
,	O
Clippinger	O
,	O
Adele	O
Goldstine	O
and	O
others	O
.	O
</s>
<s>
This	O
modification	O
reduced	O
the	O
speed	O
of	O
ENIAC	B-Device
by	O
a	O
factor	O
of	O
6	O
and	O
eliminated	O
the	O
ability	O
of	O
parallel	O
computation	O
,	O
but	O
as	O
it	O
also	O
reduced	O
the	O
reprogramming	O
time	O
to	O
hours	O
instead	O
of	O
days	O
,	O
it	O
was	O
considered	O
well	O
worth	O
the	O
loss	O
of	O
performance	O
.	O
</s>
<s>
Also	O
analysis	O
had	O
shown	O
that	O
due	O
to	O
differences	O
between	O
the	O
electronic	O
speed	O
of	O
computation	O
and	O
the	O
electromechanical	O
speed	O
of	O
input/output	O
,	O
almost	O
any	O
real-world	O
problem	O
was	O
completely	O
I/O	B-General_Concept
bound	I-General_Concept
,	O
even	O
without	O
making	O
use	O
of	O
the	O
original	O
machine	O
's	O
parallelism	O
.	O
</s>
<s>
Most	O
computations	O
would	O
still	O
be	O
I/O	B-General_Concept
bound	I-General_Concept
,	O
even	O
after	O
the	O
speed	O
reduction	O
imposed	O
by	O
this	O
modification	O
.	O
</s>
<s>
In	O
July	O
1953	O
,	O
a	O
100-word	O
expansion	O
core	O
memory	O
was	O
added	O
to	O
the	O
system	O
,	O
using	O
binary-coded	O
decimal	B-Application
,	O
excess-3	O
number	O
representation	O
.	O
</s>
<s>
To	O
support	O
this	O
expansion	O
memory	O
,	O
ENIAC	B-Device
was	O
equipped	O
with	O
a	O
new	O
Function	O
Table	O
selector	O
,	O
a	O
memory	O
address	O
selector	O
,	O
pulse-shaping	O
circuits	O
,	O
and	O
three	O
new	O
orders	O
were	O
added	O
to	O
the	O
programming	O
mechanism	O
.	O
</s>
<s>
Mechanical	O
computing	O
machines	O
have	O
been	O
around	O
since	O
Archimedes	B-Device
 '	O
time	O
(	O
see	O
:	O
Antikythera	O
mechanism	O
)	O
,	O
but	O
the	O
1930s	O
and	O
1940s	O
are	O
considered	O
the	O
beginning	O
of	O
the	O
modern	O
computer	O
era	O
.	O
</s>
<s>
ENIAC	B-Device
was	O
,	O
like	O
the	O
IBM	O
Harvard	B-Device
Mark	I-Device
I	I-Device
and	O
the	O
German	O
Z3	B-Device
,	O
able	O
to	O
run	O
an	O
arbitrary	O
sequence	O
of	O
mathematical	O
operations	O
,	O
but	O
did	O
not	O
read	O
them	O
from	O
a	O
tape	O
.	O
</s>
<s>
Like	O
the	O
British	O
Colossus	B-Device
,	O
it	O
was	O
programmed	O
by	O
plugboard	O
and	O
switches	O
.	O
</s>
<s>
ENIAC	B-Device
combined	O
full	O
,	O
Turing-complete	O
programmability	O
with	O
electronic	O
speed	O
.	O
</s>
<s>
The	B-Device
Atanasoff	I-Device
–	I-Device
Berry	I-Device
Computer	I-Device
(	O
ABC	O
)	O
,	O
ENIAC	B-Device
,	O
and	O
Colossus	B-Device
all	O
used	O
thermionic	O
valves	O
(	O
vacuum	O
tubes	O
)	O
.	O
</s>
<s>
ENIAC	B-Device
's	O
registers	O
performed	O
decimal	B-Application
arithmetic	O
,	O
rather	O
than	O
binary	O
arithmetic	O
like	O
the	O
Z3	B-Device
,	O
the	O
ABC	O
and	O
Colossus	B-Device
.	O
</s>
<s>
Like	O
the	O
Colossus	B-Device
,	O
ENIAC	B-Device
required	O
rewiring	O
to	O
reprogram	O
until	O
April	O
1948	O
.	O
</s>
<s>
In	O
June	O
1948	O
,	O
the	O
Manchester	B-Device
Baby	I-Device
ran	O
its	O
first	O
program	O
and	O
earned	O
the	O
distinction	O
of	O
first	O
electronic	O
stored-program	O
computer	O
.	O
</s>
<s>
Though	O
the	O
idea	O
of	O
a	O
stored-program	O
computer	O
with	O
combined	O
memory	O
for	O
program	O
and	O
data	O
was	O
conceived	O
during	O
the	O
development	O
of	O
ENIAC	B-Device
,	O
it	O
was	O
not	O
initially	O
implemented	O
in	O
ENIAC	B-Device
because	O
World	O
War	O
II	O
priorities	O
required	O
the	O
machine	O
to	O
be	O
completed	O
quickly	O
,	O
and	O
ENIAC	B-Device
's	O
20	O
storage	O
locations	O
would	O
be	O
too	O
small	O
to	O
hold	O
data	O
and	O
programs	O
.	O
</s>
<s>
The	O
Z3	B-Device
and	O
Colossus	B-Device
were	O
developed	O
independently	O
of	O
each	O
other	O
,	O
and	O
of	O
the	O
ABC	O
and	O
ENIAC	B-Device
during	O
World	O
War	O
II	O
.	O
</s>
<s>
The	O
Z3	B-Device
was	O
destroyed	O
by	O
the	O
Allied	O
bombing	O
raids	O
of	O
Berlin	O
in	O
1943	O
.	O
</s>
<s>
As	O
the	O
ten	O
Colossus	B-Device
machines	O
were	O
part	O
of	O
the	O
UK	O
's	O
war	O
effort	O
their	O
existence	O
remained	O
secret	O
until	O
the	O
late	O
1970s	O
,	O
although	O
knowledge	O
of	O
their	O
capabilities	O
remained	O
among	O
their	O
UK	O
staff	O
and	O
invited	O
Americans	O
.	O
</s>
<s>
ENIAC	B-Device
,	O
by	O
contrast	O
,	O
was	O
put	O
through	O
its	O
paces	O
for	O
the	O
press	O
in	O
1946	O
,	O
"	O
and	O
captured	O
the	O
world	O
's	O
imagination	O
"	O
.	O
</s>
<s>
All	O
but	O
two	O
of	O
the	O
Colossus	B-Device
machines	O
were	O
dismantled	O
in	O
1945	O
;	O
the	O
remaining	O
two	O
were	O
used	O
to	O
decrypt	O
Soviet	O
messages	O
by	O
GCHQ	O
until	O
the	O
1960s	O
.	O
</s>
<s>
The	O
public	O
demonstration	O
for	O
ENIAC	B-Device
was	O
developed	O
by	O
Snyder	O
and	O
Jennings	O
who	O
created	O
a	O
demo	O
that	O
would	O
calculate	O
the	O
trajectory	O
of	O
a	O
missile	O
in	O
15	O
seconds	O
,	O
a	O
task	O
that	O
would	O
have	O
taken	O
several	O
weeks	O
for	O
a	O
human	O
computer	O
.	O
</s>
<s>
For	O
a	O
variety	O
of	O
reasonsincluding	O
Mauchly	O
's	O
June	O
1941	O
examination	O
of	O
the	B-Device
Atanasoff	I-Device
–	I-Device
Berry	I-Device
computer	I-Device
(	O
ABC	O
)	O
,	O
prototyped	O
in	O
1939	O
by	O
John	O
Atanasoff	O
and	O
Clifford	O
Berry	O
for	O
ENIAC	B-Device
,	O
applied	O
for	O
in	O
1947	O
and	O
granted	O
in	O
1964	O
,	O
was	O
voided	O
by	O
the	O
1973	O
decision	O
of	O
the	O
landmark	O
federal	O
court	O
case	O
Honeywell	O
,	O
Inc	O
.	O
v	O
.	O
Sperry	O
Rand	O
Corp	O
..	O
</s>
<s>
The	O
decision	O
included	O
:	O
that	O
the	O
ENIAC	B-Device
inventors	O
had	O
derived	O
the	O
subject	O
matter	O
of	O
the	O
electronic	O
digital	O
computer	O
from	O
Atanasoff	O
;	O
gave	O
legal	O
recognition	O
to	O
Atanasoff	O
as	O
the	O
inventor	O
of	O
the	O
first	O
electronic	O
digital	O
computer	O
;	O
and	O
put	O
the	O
invention	O
of	O
the	O
electronic	O
digital	O
computer	O
in	O
the	O
public	O
domain	O
.	O
</s>
<s>
An	O
IBM	O
card	B-Device
reader	I-Device
was	O
attached	O
to	O
Constant	O
Transmitter	O
panel	O
3	O
and	O
an	O
IBM	O
card	B-Device
punch	I-Device
was	O
attached	O
to	O
Printer	O
Panel	O
2	O
.	O
</s>
<s>
Pieces	O
of	O
ENIAC	B-Device
are	O
held	O
by	O
the	O
following	O
institutions	O
:	O
</s>
<s>
The	O
School	O
of	O
Engineering	O
and	O
Applied	O
Science	O
at	O
the	O
University	O
of	O
Pennsylvania	O
has	O
four	O
of	O
the	O
original	O
forty	O
panels	O
(	O
Accumulator	B-General_Concept
#18	O
,	O
Constant	O
Transmitter	O
Panel	O
2	O
,	O
Master	O
Programmer	O
Panel	O
2	O
,	O
and	O
the	O
Cycling	O
Unit	O
)	O
and	O
one	O
of	O
the	O
three	O
function	O
tables	O
(	O
Function	O
Table	O
B	O
)	O
of	O
ENIAC	B-Device
(	O
on	O
loan	O
from	O
the	O
Smithsonian	O
)	O
.	O
</s>
<s>
The	O
Smithsonian	O
has	O
five	O
panels	O
(	O
Accumulators	B-General_Concept
2	O
,	O
19	O
,	O
and	O
20	O
;	O
Constant	O
Transmitter	O
panels	O
1	O
and	O
3	O
;	O
Divider	O
and	O
Square	O
Rooter	O
;	O
Function	O
Table	O
2	O
panel	O
1	O
;	O
Function	O
Table	O
3	O
panel	O
2	O
;	O
High-speed	O
Multiplier	O
panels	O
1	O
and	O
2	O
;	O
Printer	O
panel	O
1	O
;	O
Initiating	O
Unit	O
)	O
in	O
the	O
National	O
Museum	O
of	O
American	O
History	O
in	O
Washington	O
,	O
D.C.	O
(	O
but	O
apparently	O
not	O
currently	O
on	O
display	O
)	O
.	O
</s>
<s>
The	O
Computer	B-Architecture
History	I-Architecture
Museum	O
in	O
Mountain	O
View	O
,	O
California	O
has	O
three	O
panels	O
(	O
Accumulator	B-General_Concept
#12	O
,	O
Function	O
Table	O
2	O
panel	O
2	O
,	O
and	O
Printer	O
Panel	O
3	O
)	O
and	O
portable	O
function	O
table	O
C	O
on	O
display	O
(	O
on	O
loan	O
from	O
the	O
Smithsonian	O
Institution	O
)	O
.	O
</s>
<s>
The	O
University	O
of	O
Michigan	O
in	O
Ann	O
Arbor	O
has	O
four	O
panels	O
(	O
two	O
accumulators	B-General_Concept
,	O
High-speed	O
Multiplier	O
panel	O
3	O
,	O
and	O
Master	O
Programmer	O
panel	O
2	O
)	O
,	O
salvaged	O
by	O
Arthur	O
Burks	O
.	O
</s>
<s>
The	O
United	O
States	O
Army	O
Ordnance	O
Museum	O
at	O
Aberdeen	O
Proving	O
Ground	O
,	O
Maryland	O
,	O
where	O
ENIAC	B-Device
was	O
used	O
,	O
has	O
Portable	O
Function	O
Table	O
A	O
.	O
</s>
<s>
The	O
U.S.	O
Army	O
Field	O
Artillery	B-Application
Museum	O
in	O
Fort	O
Sill	O
,	O
as	O
of	O
October	O
2014	O
,	O
obtained	O
seven	O
panels	O
of	O
ENIAC	B-Device
that	O
were	O
previously	O
housed	O
by	O
The	O
Perot	O
Group	O
in	O
Plano	O
,	O
Texas	O
.	O
</s>
<s>
There	O
are	O
accumulators	B-General_Concept
#7	O
,	O
#8	O
,	O
#11	O
,	O
and	O
#17	O
;	O
panel	O
#1	O
and	O
#2	O
that	O
connected	O
to	O
function	O
table	O
#1	O
,	O
and	O
the	O
back	O
of	O
a	O
panel	O
showing	O
its	O
tubes	O
.	O
</s>
<s>
The	O
United	O
States	O
Military	O
Academy	O
at	O
West	O
Point	O
,	O
New	O
York	O
,	O
has	O
one	O
of	O
the	O
data	O
entry	O
terminals	O
from	O
the	O
ENIAC	B-Device
.	O
</s>
<s>
In	O
2014	O
the	O
museum	O
decided	O
to	O
rebuild	O
one	O
of	O
the	O
accumulator	B-General_Concept
panels	O
–	O
reconstructed	O
part	O
has	O
the	O
look	O
and	O
feel	O
of	O
a	O
simplified	O
counterpart	O
from	O
the	O
original	O
machine	O
.	O
</s>
<s>
ENIAC	B-Device
was	O
named	O
an	O
IEEE	O
Milestone	O
in	O
1987	O
.	O
</s>
<s>
In	O
1996	O
,	O
in	O
honor	O
of	O
the	O
ENIAC	B-Device
's	O
50th	O
anniversary	O
,	O
The	O
University	O
of	O
Pennsylvania	O
sponsored	O
a	O
project	O
named	O
,	O
"	O
ENIAC-on-a-Chip	O
"	O
,	O
where	O
a	O
very	O
small	O
silicon	O
computer	O
chip	O
measuring	O
7.44mm	O
by	O
5.29mm	O
was	O
built	O
with	O
the	O
same	O
functionality	O
as	O
ENIAC	B-Device
.	O
</s>
<s>
Although	O
this	O
20MHz	O
chip	O
was	O
many	O
times	O
faster	O
than	O
ENIAC	B-Device
,	O
it	O
had	O
but	O
a	O
fraction	O
of	O
the	O
speed	O
of	O
its	O
contemporary	O
microprocessors	O
in	O
the	O
late	O
1990s	O
.	O
</s>
<s>
In	O
1997	O
,	O
the	O
six	O
women	O
who	O
did	O
most	O
of	O
the	O
programming	O
of	O
ENIAC	B-Device
were	O
inducted	O
into	O
the	O
Technology	O
International	O
Hall	O
of	O
Fame	O
.	O
</s>
<s>
The	O
role	O
of	O
the	O
ENIAC	B-Device
programmers	O
is	O
treated	O
in	O
a	O
2010	O
documentary	O
film	O
titled	O
Top	O
Secret	O
Rosies	O
:	O
The	O
Female	O
"	O
Computers	O
"	O
of	O
WWII	O
by	O
LeAnn	O
Erickson	O
.	O
</s>
<s>
A	O
2014	O
documentary	O
short	O
,	O
The	O
Computers	O
by	O
Kate	O
McMahon	O
,	O
tells	O
of	O
the	O
story	O
of	O
the	O
six	O
programmers	O
;	O
this	O
was	O
the	O
result	O
of	O
20	O
years	O
 '	O
research	O
by	O
Kathryn	O
Kleiman	O
and	O
her	O
team	O
as	O
part	O
of	O
the	O
ENIAC	B-Device
Programmers	O
Project	O
.	O
</s>
<s>
In	O
2022	O
Grand	O
Central	O
Publishing	O
released	O
Proving	O
Ground	O
by	O
Kathy	O
Kleiman	O
,	O
a	O
hardcover	O
biography	O
about	O
the	O
six	O
ENIAC	B-Device
programmers	O
and	O
their	O
efforts	O
to	O
translate	O
block	O
diagrams	O
and	O
electronic	B-Application
schematics	I-Application
of	O
the	O
ENIAC	B-Device
,	O
then	O
under	O
construction	O
,	O
into	O
programs	O
that	O
would	O
be	O
loaded	O
into	O
and	O
run	O
on	O
ENIAC	B-Device
once	O
it	O
was	O
available	O
for	O
use	O
.	O
</s>
<s>
In	O
2011	O
,	O
in	O
honor	O
of	O
the	O
65th	O
anniversary	O
of	O
the	O
ENIAC	B-Device
's	O
unveiling	O
,	O
the	O
city	O
of	O
Philadelphia	O
declared	O
February	O
15	O
as	O
ENIAC	B-Device
Day	I-Device
.	O
</s>
<s>
The	O
ENIAC	B-Device
celebrated	O
its	O
70th	O
anniversary	O
on	O
February	O
15	O
,	O
2016	O
.	O
</s>
