<s>
OXO	B-Application
is	O
a	O
video	O
game	O
developed	O
by	O
A	O
S	O
Douglas	O
in	O
1952	O
which	O
simulates	O
a	O
game	O
of	O
noughts	B-Application
and	I-Application
crosses	I-Application
(	O
tic-tac-toe	O
)	O
.	O
</s>
<s>
It	O
was	O
one	O
of	O
the	O
first	O
games	O
developed	O
in	O
the	O
early	B-Application
history	I-Application
of	I-Application
video	I-Application
games	I-Application
.	O
</s>
<s>
The	O
program	O
was	O
written	O
for	O
the	O
Electronic	B-Device
Delay	I-Device
Storage	I-Device
Automatic	I-Device
Calculator	I-Device
(	O
EDSAC	B-Device
)	O
.	O
</s>
<s>
EDSAC	B-Device
was	O
one	O
of	O
the	O
first	O
stored-program	O
computers	O
,	O
with	O
memory	O
that	O
could	O
be	O
read	B-Architecture
from	I-Architecture
or	I-Architecture
written	I-Architecture
to	I-Architecture
,	O
and	O
had	O
three	O
small	O
cathode	B-Device
ray	I-Device
tube	I-Device
screens	O
to	O
display	O
the	O
state	O
of	O
the	O
memory	O
;	O
Douglas	O
re-purposed	O
one	O
screen	O
to	O
demonstrate	O
portraying	O
other	O
information	O
to	O
the	O
user	O
,	O
such	O
as	O
the	O
state	O
of	O
a	O
noughts	B-Application
and	I-Application
crosses	I-Application
game	O
.	O
</s>
<s>
OXO	B-Application
,	O
along	O
with	O
a	O
draughts	O
game	O
by	O
Christopher	O
Strachey	O
completed	O
around	O
the	O
same	O
time	O
,	O
is	O
one	O
of	O
the	O
earliest	O
known	O
games	O
to	O
display	O
visuals	O
on	O
an	O
electronic	O
screen	O
.	O
</s>
<s>
Under	O
some	O
definitions	O
,	O
it	O
thus	O
may	O
qualify	O
as	O
the	B-Application
first	I-Application
video	I-Application
game	I-Application
,	O
though	O
other	O
definitions	O
exclude	O
it	O
due	O
to	O
its	O
lack	O
of	O
moving	O
or	O
real-time	O
updating	O
graphics	O
.	O
</s>
<s>
The	O
Electronic	B-Device
Delay	I-Device
Storage	I-Device
Automatic	I-Device
Calculator	I-Device
(	O
EDSAC	B-Device
)	O
mainframe	O
computer	O
was	O
built	O
in	O
the	O
University	O
of	O
Cambridge	O
's	O
Mathematical	O
Laboratory	O
between	O
1946	O
and	O
6	O
May	O
1949	O
,	O
when	O
it	O
ran	O
its	O
first	O
program	O
,	O
and	O
remained	O
in	O
use	O
until	O
11	O
July	O
1958	O
.	O
</s>
<s>
The	O
EDSAC	B-Device
was	O
one	O
of	O
the	O
first	O
stored-program	O
computers	O
,	O
with	O
memory	O
that	O
could	O
be	O
read	B-Architecture
from	I-Architecture
or	I-Architecture
written	I-Architecture
to	I-Architecture
,	O
and	O
filled	O
an	O
entire	O
room	O
;	O
it	O
included	O
three	O
35×16	O
dot	O
matrix	O
cathode	B-Device
ray	I-Device
tubes	I-Device
(	O
CRTs	O
)	O
to	O
graphically	O
display	O
the	O
state	O
of	O
the	O
computer	O
's	O
memory	O
.	O
</s>
<s>
Douglas	O
used	O
the	O
EDSAC	B-Device
to	O
simulate	O
a	O
game	O
of	O
noughts	B-Application
and	I-Application
crosses	I-Application
,	O
and	O
display	O
the	O
state	O
of	O
the	O
game	O
on	O
the	O
screen	O
.	O
</s>
<s>
Douglas	O
did	O
not	O
give	O
the	O
game	O
a	O
name	O
beyond	O
"	O
noughts	B-Application
and	I-Application
crosses	I-Application
"	O
;	O
the	O
name	O
OXO	B-Application
first	O
appeared	O
as	O
the	O
name	O
of	O
the	O
simulation	O
file	O
created	O
by	O
computer	O
historian	O
Martin	O
Campbell-Kelly	O
while	O
creating	O
a	O
simulation	O
of	O
the	O
EDSAC	B-Device
several	O
decades	O
later	O
.	O
</s>
<s>
Around	O
the	O
same	O
time	O
that	O
OXO	B-Application
was	O
completed	O
,	O
Christopher	O
Strachey	O
expanded	O
a	O
draughts	O
program	O
he	O
had	O
originally	O
written	O
in	O
1951	O
and	O
ported	O
it	O
to	O
the	O
Ferranti	B-Device
Mark	I-Device
1	I-Device
,	O
which	O
showed	O
the	O
state	O
of	O
the	O
game	O
on	O
a	O
CRT	B-Device
display	I-Device
.	O
</s>
<s>
OXO	B-Application
and	O
Strachey	O
's	O
draughts	O
program	O
are	O
the	O
earliest	O
known	O
games	O
to	O
display	O
visuals	O
on	O
an	O
electronic	O
screen	O
,	O
though	O
it	O
is	O
unclear	O
which	O
of	O
the	O
two	O
games	O
was	O
displayed	O
first	O
.	O
</s>
<s>
As	O
it	O
ran	O
on	O
a	O
computing	O
device	O
and	O
used	O
a	O
graphical	O
display	O
,	O
OXO	B-Application
is	O
considered	O
under	O
some	O
definitions	O
to	O
be	O
a	O
contender	O
for	O
the	B-Application
first	I-Application
video	I-Application
game	I-Application
,	O
though	O
under	O
others	O
it	O
does	O
not	O
due	O
to	O
its	O
lack	O
of	O
moving	O
graphics	O
or	O
graphics	O
which	O
update	O
continuously	O
.	O
</s>
<s>
Each	O
game	O
was	O
played	O
by	O
one	O
user	O
against	O
an	O
artificially	B-Application
intelligent	I-Application
opponent	O
,	O
which	O
could	O
play	O
a	O
"	O
perfect	O
"	O
game	O
.	O
</s>
<s>
OXO	B-Application
was	O
not	O
available	O
to	O
the	O
general	O
public	O
and	O
could	O
only	O
be	O
played	O
in	O
the	O
University	O
of	O
Cambridge	O
's	O
Mathematical	O
Laboratory	O
by	O
special	O
permission	O
,	O
as	O
the	O
EDSAC	B-Device
could	O
not	O
be	O
moved	O
,	O
and	O
both	O
the	O
computer	O
and	O
the	O
game	O
were	O
only	O
intended	O
for	O
academic	O
research	O
purposes	O
.	O
</s>
