<s>
The	O
Sharp	B-Device
QT-8D	I-Device
Micro	O
Compet	O
,	O
a	O
small	O
electronic	O
desktop	O
calculator	B-Application
,	O
was	O
the	O
first	O
mass-produced	O
calculator	B-Application
to	O
have	O
its	O
logic	O
circuitry	O
entirely	O
implemented	O
with	O
LSI	O
(	O
large-scale	O
integration	O
)	O
integrated	O
circuits	O
(	O
ICs	O
)	O
based	O
on	O
MOS	O
(	O
metal-oxide-semiconductor	B-Architecture
)	O
technology	O
.	O
</s>
<s>
When	O
it	O
was	O
introduced	O
in	O
late	O
1969	O
,	O
it	O
was	O
one	O
of	O
the	O
smallest	O
electronic	O
calculators	B-Application
ever	O
produced	O
commercially	O
.	O
</s>
<s>
Previous	O
electronic	O
calculators	B-Application
had	O
been	O
about	O
the	O
size	O
of	O
a	O
typewriter	O
and	O
had	O
logic	O
circuits	O
built	O
from	O
numerous	O
discrete	O
transistors	B-Application
and	O
diodes	O
or	O
small	O
-	O
to	O
medium-scale	O
ICs	O
.	O
</s>
<s>
The	O
QT-8D	O
was	O
released	O
in	O
Japan	O
at	O
a	O
price	O
of	O
99,800	O
Japanese	O
yen	O
,	O
a	O
new	O
low	O
for	O
electronic	O
calculators	B-Application
.	O
</s>
<s>
Like	O
many	O
calculators	B-Application
intended	O
for	O
business	O
use	O
,	O
the	O
QT-8D	O
adds	O
and	O
subtracts	O
in	O
the	O
style	O
of	O
an	O
adding	O
machine	O
:	O
after	O
entering	O
each	O
number	O
,	O
the	O
operator	O
presses	O
either	O
the	O
white	O
key	O
,	O
to	O
add	O
it	O
to	O
the	O
current	O
total	O
,	O
or	O
the	O
red	O
key	O
,	O
to	O
subtract	O
it	O
from	O
the	O
total	O
.	O
</s>
<s>
The	O
decimal	O
point	O
is	O
"	O
floating	O
"	O
—	O
it	O
is	O
positioned	O
automatically	O
by	O
the	O
calculator	B-Application
logic	O
.	O
</s>
<s>
This	O
was	O
an	O
advanced	O
feature	O
for	O
the	O
time	O
;	O
many	O
desk	O
calculators	B-Application
of	O
this	O
era	O
had	O
fixed	O
decimal	O
points	O
and	O
required	O
very	O
wide	O
displays	O
to	O
maintain	O
a	O
minimum	O
level	O
of	O
precision	O
across	O
the	O
entire	O
range	O
of	O
numbers	O
available	O
.	O
</s>
<s>
The	O
display	O
is	O
a	O
vacuum	B-General_Concept
fluorescent	I-General_Concept
display	I-General_Concept
,	O
the	O
first	O
such	O
display	O
ever	O
used	O
in	O
a	O
production	O
calculator	B-Application
.	O
</s>
<s>
These	O
Iseden	O
"	O
itron	O
"	O
tubes	O
have	O
a	O
unique	O
digit	O
style	O
which	O
is	O
very	O
different	O
from	O
today	O
's	O
seven-segment	B-General_Concept
displays	I-General_Concept
.	O
</s>
<s>
Each	O
of	O
the	O
four	O
LSI	O
ICs	O
contains	O
the	O
equivalent	O
of	O
about	O
700	O
to	O
900	O
transistors	B-Application
,	O
and	O
the	O
ICs	O
are	O
named	O
based	O
on	O
their	O
functions	O
.	O
</s>
<s>
By	O
the	O
standards	O
of	O
its	O
time	O
,	O
the	O
QT-8D	O
is	O
quite	O
a	O
fast	O
calculator	B-Application
.	O
</s>
<s>
Dividing	O
99999999	O
by	O
1	O
,	O
which	O
is	O
the	O
worst	O
case	O
for	O
the	O
simple	O
long	B-Algorithm
division	I-Algorithm
method	O
used	O
on	O
many	O
calculators	B-Application
,	O
takes	O
roughly	O
200	O
milliseconds	O
,	O
and	O
addition	O
and	O
subtraction	O
are	O
nearly	O
instantaneous	O
.	O
</s>
<s>
The	O
QT-8D	O
is	O
much	O
smaller	O
than	O
earlier	O
calculators	B-Application
;	O
it	O
is	O
about	O
long	O
,	O
wide	O
,	O
and	O
high	O
,	O
and	O
it	O
weighs	O
about	O
.	O
</s>
<s>
Its	O
MOS	O
LSI	O
technology	O
also	O
greatly	O
reduced	O
its	O
power	O
usage	O
compared	O
to	O
previous	O
calculators	B-Application
:	O
it	O
has	O
an	O
AC	O
power	O
consumption	O
rating	O
of	O
only	O
7	O
watts	O
.	O
</s>
<s>
This	O
low	O
power	O
usage	O
made	O
it	O
feasible	O
for	O
Sharp	O
to	O
introduce	O
a	O
battery-powered	O
version	O
,	O
the	O
QT-8B	B-Device
,	O
in	O
mid-1970	O
.	O
</s>
<s>
This	O
was	O
the	O
first	O
mass-produced	O
electronic	O
calculator	B-Application
to	O
be	O
battery-powered	O
.	O
</s>
<s>
It	O
replaced	O
the	O
QT-8D	O
'	O
s	O
integrated	O
power	O
supply	O
with	O
a	O
rechargeable	B-Architecture
battery	I-Architecture
pack	O
,	O
but	O
it	O
was	O
otherwise	O
nearly	O
identical	O
to	O
the	O
QT-8D	O
.	O
</s>
<s>
The	O
four	O
ICs	O
of	O
the	O
QT-8D	O
and	O
QT-8B	B-Device
were	O
also	O
used	O
as	O
the	O
basis	O
of	O
the	O
Sharp	B-Device
EL-8	I-Device
,	O
one	O
of	O
the	O
first	O
mass-produced	O
hand-held	O
electronic	O
calculators	B-Application
,	O
introduced	O
in	O
1971	O
.	O
</s>
<s>
Sharp	O
also	O
built	O
OEM	O
versions	O
of	O
the	O
QT-8D	O
for	O
the	O
Swedish	O
office	O
machine	O
company	O
Facit	O
and	O
its	O
subsidiary	O
Addo	O
,	O
which	O
sold	O
them	O
as	O
the	O
Facit	B-Device
1115	I-Device
and	O
the	O
Addo-X	B-Device
9354	I-Device
.	O
</s>
<s>
The	O
Soviet-built	O
Elektronika	B-Device
EKVM	I-Device
24-71	I-Device
,	O
introduced	O
in	O
1971	O
,	O
was	O
reverse-engineered	O
from	O
the	O
Sharp	B-Device
QT-8D	I-Device
with	O
minor	O
differences	O
.	O
</s>
