<s>
The	O
Royal	B-Device
Radar	I-Device
Establishment	I-Device
Automatic	I-Device
Computer	I-Device
,	O
or	O
the	O
RREAC	O
,	O
was	O
an	O
early	O
solid-state	O
computer	O
in	O
1962	O
.	O
</s>
<s>
It	O
was	O
made	O
with	O
transistors	B-Application
;	O
many	O
of	O
Britain	O
's	O
previous	O
experimental	O
computers	O
used	O
the	O
thermionic	O
valve	O
,	O
also	O
known	O
as	O
a	O
vacuum	O
tube	O
.	O
</s>
<s>
Britain	O
had	O
built	O
the	O
world	O
's	O
first	O
electronic	O
computer	O
,	O
the	O
Colossus	B-Device
computer	I-Device
,	O
during	O
the	O
war	O
at	O
Bletchley	O
Park	O
in	O
late	O
1943	O
and	O
early	O
1944	O
,	O
and	O
the	O
world	O
's	O
first	O
stored-program	O
computer	O
,	O
the	O
Manchester	B-Device
Baby	I-Device
,	O
on	O
21	O
June	O
1948	O
.	O
</s>
<s>
The	O
Germans	O
had	O
built	O
the	O
electro-mechanical	O
Z3	B-Device
in	O
1941	O
in	O
Berlin	O
,	O
which	O
used	O
relays	O
.	O
</s>
<s>
The	O
world	O
's	O
first	O
digital	O
computing	O
device	O
was	O
the	B-Device
Atanasoff	I-Device
–	I-Device
Berry	I-Device
Computer	I-Device
in	O
1942	O
.	O
</s>
<s>
ENIAC	B-Device
was	O
built	O
in	O
1946	O
at	O
the	O
Moore	O
School	O
of	O
Electrical	O
Engineering	O
at	O
the	O
University	O
of	O
Pennsylvania	O
.	O
</s>
<s>
ENIAC	B-Device
and	O
Colossus	B-Device
both	O
claim	O
to	O
be	O
the	O
world	O
's	O
first	O
electronic	O
computer	O
.	O
</s>
<s>
Electronic	B-Device
Delay	I-Device
Storage	I-Device
Automatic	I-Device
Calculator	I-Device
(	O
EDSAC	B-Device
)	O
ran	O
its	O
first	O
programs	O
on	O
6	O
May	O
1949	O
at	O
the	O
University	O
of	O
Cambridge	O
Mathematical	O
Laboratory	O
about	O
a	O
month	O
after	O
the	O
Manchester	B-Device
Mark	I-Device
1	I-Device
was	O
put	O
to	O
research	O
work	O
at	O
the	O
University	B-Device
of	I-Device
Manchester	I-Device
.	O
</s>
<s>
Manchester	O
University	O
led	O
the	O
way	O
again	O
in	O
1962	O
with	O
its	O
Atlas	B-Device
Computer	I-Device
,	O
then	O
said	O
to	O
be	O
the	O
most	O
powerful	O
computer	O
in	O
the	O
world	O
,	O
being	O
one	O
of	O
the	O
world	O
's	O
first	O
supercomputers	O
.	O
</s>
<s>
Three	O
were	O
built	O
:	O
the	O
first	O
for	O
Manchester	O
University	O
,	O
and	O
one	O
each	O
for	O
BP	O
and	O
for	O
the	O
Atlas	B-Device
Computer	I-Device
Laboratory	O
in	O
Oxfordshire	O
.	O
</s>
<s>
Work	O
in	O
transistor	B-Application
technology	O
at	O
RRE	O
took	O
place	O
in	O
the	O
Physics	O
Department	O
under	O
Dr	O
R.A.	O
Smith	O
.	O
</s>
<s>
It	O
was	O
earlier	O
known	O
as	O
the	O
RRE	O
All-Transistor	O
Computer	O
.	O
</s>
<s>
RREAC	O
had	O
a	O
36-bit	O
word	O
and	O
24K	O
words	O
of	O
core	O
store	O
,	O
and	O
used	O
five-hole	O
paper	O
tape	O
for	O
input	O
and	O
output	O
,	O
and	O
magnetic	B-Architecture
tape	I-Architecture
for	O
data	O
storage	O
.	O
</s>
<s>
The	O
world	O
's	O
first	O
transistorised	B-Device
computer	I-Device
was	O
the	O
Manchester	O
Transistor	B-Application
Computer	O
,	O
operational	O
in	O
1953	O
.	O
</s>
<s>
The	O
1955	O
Harwell	B-Device
CADET	I-Device
is	O
a	O
contender	O
for	O
the	O
title	O
of	O
first	O
fully	O
transistorised	B-Device
computer	I-Device
.	O
</s>
<s>
RREAC	O
used	O
ALGOL	B-Language
60	I-Language
as	O
its	O
programming	O
language	O
-	O
the	O
first	O
computer	O
language	O
to	O
use	O
nested	O
functions	O
,	O
and	O
the	O
ancestor	O
of	O
some	O
of	O
today	O
's	O
main	O
programming	O
languages	O
.	O
</s>
