<s>
A	O
mechanical	B-Device
computer	I-Device
is	O
a	O
computer	O
built	O
from	O
mechanical	O
components	O
such	O
as	O
levers	O
and	O
gears	B-Application
rather	O
than	O
electronic	O
components	O
.	O
</s>
<s>
The	O
most	O
common	O
examples	O
are	O
adding	O
machines	O
and	O
mechanical	B-Device
counters	I-Device
,	O
which	O
use	O
the	O
turning	O
of	O
gears	B-Application
to	O
increment	O
output	O
displays	O
.	O
</s>
<s>
More	O
complex	O
examples	O
could	O
carry	O
out	O
multiplication	O
and	O
division	O
—	O
Friden	O
used	O
a	O
moving	O
head	O
which	O
paused	O
at	O
each	O
column	O
—	O
and	O
even	O
differential	B-Device
analysis	I-Device
.	O
</s>
<s>
Mechanical	B-Device
computers	I-Device
can	O
be	O
either	O
analog	O
,	O
using	O
continuous	O
or	O
smooth	O
mechanisms	O
such	O
as	O
curved	O
plates	O
or	O
slide	O
rules	O
for	O
computations	O
;	O
or	O
discrete	O
,	O
which	O
use	O
mechanisms	O
like	O
pinwheels	O
and	O
gears	B-Application
.	O
</s>
<s>
Mechanical	B-Device
computers	I-Device
reached	O
their	O
zenith	O
during	O
World	O
War	O
II	O
,	O
when	O
they	O
formed	O
the	O
basis	O
of	O
complex	O
bombsights	B-Application
including	O
the	O
Norden	B-Device
,	O
as	O
well	O
as	O
the	O
similar	O
devices	O
for	O
ship	O
computations	O
such	O
as	O
the	O
US	O
Torpedo	B-Device
Data	I-Device
Computer	I-Device
or	O
British	O
Admiralty	B-Device
Fire	I-Device
Control	I-Device
Table	I-Device
.	O
</s>
<s>
Mechanical	B-Device
computers	I-Device
continued	O
to	O
be	O
used	O
into	O
the	O
1960s	O
,	O
but	O
were	O
quickly	O
replaced	O
by	O
electronic	O
calculators	O
,	O
which	O
—	O
with	O
cathode-ray	B-Device
tube	I-Device
output	O
—	O
emerged	O
in	O
the	O
mid-1960s	O
.	O
</s>
<s>
The	O
use	O
of	O
mechanical	B-Device
computers	I-Device
declined	O
in	O
the	O
1970s	O
and	O
was	O
rare	O
by	O
the	O
1980s	O
,	O
when	O
digital	O
computers	O
prevailed	O
.	O
</s>
<s>
In	O
2016	O
,	O
NASA	O
announced	O
that	O
its	O
Automaton	O
Rover	O
for	O
Extreme	O
Environments	O
program	O
would	O
use	O
a	O
mechanical	B-Device
computer	I-Device
to	O
operate	O
in	O
the	O
harsh	O
environmental	O
conditions	O
found	O
on	O
Venus	O
.	O
</s>
<s>
Cosmic	O
Engine	O
,	O
1092	O
–	O
Su	O
Song	O
's	O
hydro-mechanical	O
astronomical	O
clock	B-Application
tower	I-Application
invented	O
during	O
the	O
Song	O
dynasty	O
,	O
which	O
featured	O
the	O
use	O
of	O
an	O
early	O
escapement	O
mechanism	O
applied	O
to	O
clockwork	O
.	O
</s>
<s>
Castle	O
clock	O
,	O
1206	O
–	O
Al-Jazari	O
'	O
s	O
castle	O
clock	O
,	O
a	O
hydropowered	O
mechanical	O
astronomical	O
clock	O
,	O
was	O
the	O
earliest	O
programmable	B-General_Concept
analog	O
computer	O
.	O
</s>
<s>
Analytical	B-Device
Engine	I-Device
,	O
1837	O
–	O
A	O
later	O
Charles	O
Babbage	O
device	O
that	O
could	O
be	O
said	O
to	O
encapsulate	O
most	O
of	O
the	O
elements	O
of	O
modern	O
computers	O
.	O
</s>
<s>
Ball-and-disk	B-Device
integrator	I-Device
,	O
1886	O
–	O
William	O
Thomson	O
used	O
it	O
in	O
his	O
Harmonic	B-Device
Analyser	I-Device
to	O
measure	O
tide	O
heights	O
by	O
calculating	O
coefficients	O
of	O
a	O
Fourier	O
series	O
.	O
</s>
<s>
Percy	O
Ludgate	O
's	O
1909	O
Analytical	O
Machine	O
–	O
The	O
2nd	O
of	O
only	O
two	O
mechanical	O
Analytical	B-Device
Engines	I-Device
ever	O
designed	O
.	O
</s>
<s>
Admiralty	B-Device
Fire	I-Device
Control	I-Device
Table	I-Device
,	O
1922	O
-	O
Royal	O
Navy	O
advanced	O
fire	O
control	O
computer	O
.	O
</s>
<s>
Kerrison	B-Device
Predictor	I-Device
(	O
"	O
late	O
1930s	O
"	O
?	O
)	O
</s>
<s>
Mark	B-Device
I	I-Device
Fire	I-Device
Control	I-Device
Computer	I-Device
,	O
deployed	O
by	O
the	O
United	O
States	O
Navy	O
during	O
World	O
War	O
II	O
(	O
1939	O
to	O
1945	O
)	O
and	O
up	O
to	O
1969	O
or	O
later	O
.	O
</s>
<s>
MONIAC	B-Device
,	O
1949	O
–	O
An	O
analog	O
computer	O
used	O
to	O
model	O
or	O
simulate	O
the	O
UK	O
economy	O
.	O
</s>
<s>
Early	O
electrically	O
powered	O
computers	O
constructed	O
from	O
switches	O
and	O
relay	O
logic	O
rather	O
than	O
vacuum	O
tubes	O
(	O
thermionic	O
valves	O
)	O
or	O
transistors	B-Application
(	O
from	O
which	O
later	O
electronic	O
computers	O
were	O
constructed	O
)	O
are	O
classified	O
as	O
electro-mechanical	O
computers	O
.	O
</s>
<s>
Name	O
Country	O
Year	O
Remarks	O
Reference	O
Automatic	O
Relay	O
Computer	O
UK	O
1948	O
The	O
Booths	O
,	O
experimentalARRA	O
Netherlands1952	O
experimentalBARK	O
Sweden1952experimentalFACOM-100	O
Japan1954Fujitsu	O
commercialFACOM-128Japan1956commercialHarwell	O
computerUK1951	O
later	O
known	O
as	O
WITCHHarvard	O
Mark	O
I	O
United	O
States1944	O
"	O
IBM	B-Device
Automatic	I-Device
Sequence	I-Device
Controlled	I-Device
Calculator	I-Device
"	O
Harvard	O
Mark	O
IIUSA1947	O
"	O
Aiken	O
Relay	O
Calculator	O
"	O
IBM	O
SSECUSA1948Imperial	O
College	O
Computing	O
Engine	O
(	O
ICCE	O
)	O
UK1951Electro-mechanicalOffice	O
of	O
Naval	O
Research	O
ONR	O
Relay	O
ComputerUSA1949	O
6-bit	O
,	O
drum	O
storage	O
,	O
but	O
electro-mechanical	O
relay	O
ALU	O
based	O
on	O
Atlas	B-Device
,	O
formerly	O
Navy	O
cryptology	O
computer	O
ABEL	O
OPREMAEast	O
Germany1955Commercial	O
use	O
at	O
Zeiss	O
Optical	O
in	O
JenaRVM-1Soviet	O
Union1957Alexander	O
KronrodSAPOCzechoslovakia1957SimonUSA1950	O
Hobbyist	O
logic	O
demonstrator	O
magazine	O
articleZ2Germany1940Konrad	O
ZuseZ3Germany1941	O
ZuseZ4	O
Germany	O
1945	O
ZuseZ5Germany	O
1953	O
ZuseZ11Germany1955	O
Zuse	O
,	O
commercial	O
Bell	O
Labs	O
Model	O
IUSA1940	O
George	O
Stibitz	O
,	O
"	O
Complex	O
Number	O
Calculator	O
"	O
,	O
450	O
relays	O
and	O
crossbar	O
switches	O
,	O
demonstrated	O
remote	O
access	O
1940	O
,	O
used	O
until	O
1948	O
Bell	O
Labs	O
Model	O
IIUSA1943	O
"	O
Relay	O
Interpolator	O
"	O
,	O
used	O
for	O
wartime	O
work	O
,	O
shut	O
down	O
1962Bell	O
Labs	O
Model	O
IIIUSA1944	O
"	O
Ballistic	O
Computer	O
"	O
,	O
used	O
until	O
1949Bell	O
Labs	O
Model	O
IVUSA1945Navy	O
"	O
Mark	O
22	O
Error	O
Detector	O
"	O
,	O
used	O
until	O
1961Bell	O
Labs	O
Model	O
VUSA1946	O
,	O
1947Two	O
units	O
delivered	O
,	O
general-purpose	O
,	O
built	O
in	O
trigonometric	O
functions	O
,	O
floating-point	O
arithmeticBell	O
Labs	O
Model	O
VIUSA1949General	O
purpose	O
,	O
simplified	O
Model	B-Device
V	I-Device
with	O
several	O
enhancementsUnnamed	O
cryptanalysis	O
multiplierUK1937Turing	O
Relay	O
Computer	O
USA2006Harry	O
Porter	O
's	O
Relay	O
Computer	O
,	O
demonstrator/hobby	O
,	O
but	O
integrated	O
circuit	O
memory	O
.	O
</s>
