<s>
The	O
Sinclair	B-Device
Scientific	I-Device
calculator	B-Application
was	O
a	O
12-function	O
,	O
pocket-sized	O
scientific	O
calculator	B-Application
introduced	O
in	O
1974	O
,	O
dramatically	O
undercutting	O
in	O
price	O
other	O
calculators	B-Application
available	O
at	O
the	O
time	O
.	O
</s>
<s>
The	O
Sinclair	B-Device
Scientific	I-Device
Programmable	O
,	O
released	O
a	O
year	O
later	O
,	O
was	O
advertised	O
as	O
the	O
first	O
budget	O
programmable	O
calculator	B-Application
.	O
</s>
<s>
Significant	O
modifications	O
to	O
the	O
algorithms	O
used	O
meant	O
that	O
a	O
chipset	B-Device
intended	O
for	O
a	O
four-function	O
calculator	B-Application
was	O
able	O
to	O
process	O
scientific	O
functions	O
,	O
but	O
at	O
the	O
cost	O
of	O
reduced	O
speed	O
and	O
accuracy	O
.	O
</s>
<s>
Compared	O
to	O
contemporary	O
scientific	O
calculators	B-Application
,	O
some	O
functions	O
were	O
slow	O
to	O
execute	O
,	O
and	O
others	O
had	O
limited	O
accuracy	O
or	O
gave	O
the	O
wrong	O
answer	O
,	O
but	O
the	O
cost	O
of	O
the	O
Sinclair	O
was	O
a	O
fraction	O
of	O
the	O
cost	O
of	O
competing	O
calculators	B-Application
.	O
</s>
<s>
In	O
1972	O
,	O
Hewlett-Packard	O
launched	O
the	O
HP-35	B-Device
,	O
the	O
world	O
's	O
first	O
handheld	O
scientific	O
calculator	B-Application
.	O
</s>
<s>
From	O
1971	O
Texas	O
Instruments	O
had	O
been	O
making	O
available	O
the	O
building	O
block	O
for	O
a	O
simple	O
calculator	B-Application
on	O
a	O
single	O
chip	O
and	O
the	O
TMS0803	O
chipset	B-Device
appeared	O
in	O
a	O
number	O
of	O
Sinclair	O
calculators	B-Application
.	O
</s>
<s>
Clive	O
Sinclair	O
wanted	O
to	O
design	O
a	O
calculator	B-Application
to	O
compete	O
with	O
the	O
HP-35	B-Device
using	O
this	O
series	O
of	O
chips	O
.	O
</s>
<s>
The	O
Sinclair	B-Device
Scientific	I-Device
first	O
appeared	O
in	O
a	O
case	O
derived	O
from	O
that	O
of	O
the	O
Sinclair	B-Device
Cambridge	I-Device
,	O
but	O
it	O
was	O
not	O
part	O
of	O
the	O
same	O
range	O
.	O
</s>
<s>
The	O
Sinclair	B-Device
Scientific	I-Device
Programmable	O
was	O
introduced	O
in	O
August	O
1975	O
,	O
and	O
was	O
larger	O
than	O
the	O
Sinclair	B-Device
Scientific	I-Device
,	O
at	O
.	O
</s>
<s>
It	O
was	O
advertised	O
as	O
"	O
the	O
first	O
...	O
calculator	B-Application
to	O
offer	O
a	O
...	O
programming	O
facility	O
...	O
at	O
a	O
price	O
within	O
the	O
reach	O
of	O
the	O
general	O
public	O
,	O
"	O
but	O
was	O
limited	O
by	O
having	O
only	O
24	O
program	O
steps	O
.	O
</s>
<s>
Both	O
the	O
Sinclair	B-Device
Scientific	I-Device
and	O
the	O
Sinclair	B-Device
Scientific	I-Device
Programmable	O
were	O
manufactured	O
in	O
England	O
,	O
like	O
all	O
other	O
Sinclair	O
calculators	B-Application
except	O
the	O
Sinclair	B-Device
President	I-Device
.	O
</s>
<s>
The	O
HP-35	B-Device
used	O
five	O
chips	O
,	O
and	O
had	O
a	O
been	O
developed	O
by	O
twenty	O
engineers	O
at	O
a	O
cost	O
of	O
a	O
million	O
dollars	O
,	O
leading	O
the	O
Texas	O
Instruments	O
engineers	O
to	O
think	O
that	O
Sinclair	O
's	O
aim	O
to	O
build	O
a	O
scientific	O
calculator	B-Application
around	O
the	O
TMS0805	O
chip	O
,	O
which	O
could	O
barely	O
handle	O
four-function	O
arithmetic	O
,	O
was	O
impossible	O
.	O
</s>
<s>
Constants	O
,	O
rather	O
than	O
being	O
stored	O
in	O
the	O
calculator	B-Application
,	O
were	O
printed	O
on	O
the	O
case	O
below	O
the	O
screen	O
.	O
</s>
<s>
It	O
displays	O
only	O
in	O
scientific	O
notation	O
,	O
with	O
a	O
five	O
digit	O
mantissa	B-Algorithm
and	O
a	O
two	O
digit	O
exponent	O
,	O
although	O
a	O
sixth	O
digit	O
of	O
the	O
mantissa	B-Algorithm
was	O
stored	O
internally	O
.	O
</s>
<s>
By	O
not	O
using	O
regular	O
floating	B-Algorithm
point	I-Algorithm
numbers	I-Algorithm
,	O
which	O
require	O
many	O
instructions	O
to	O
keep	O
the	O
decimal	O
point	O
in	O
the	O
right	O
place	O
,	O
some	O
space	O
was	O
freed	O
up	O
.	O
</s>
<s>
The	O
design	O
of	O
the	O
algorithms	O
meant	O
that	O
some	O
calculations	O
,	O
such	O
as	O
arccos0.2	O
,	O
could	O
take	O
up	O
to	O
15	O
seconds	O
,	O
whereas	O
the	O
HP-35	B-Device
was	O
designed	O
to	O
complete	O
calculations	O
in	O
under	O
a	O
second	O
.	O
</s>
<s>
Ken	O
Shirriff	O
,	O
an	O
employee	O
of	O
Google	B-Application
,	O
reverse	O
engineered	O
a	O
Sinclair	B-Device
Scientific	I-Device
and	O
built	O
a	O
simulator	O
using	O
the	O
original	O
algorithms	O
.	O
</s>
<s>
The	O
Sinclair	B-Device
Scientific	I-Device
Programmable	O
was	O
introduced	O
in	O
1975	O
,	O
with	O
the	O
same	O
case	O
as	O
the	O
Sinclair	B-Device
Oxford	I-Device
.	O
</s>
<s>
It	O
was	O
larger	O
than	O
the	O
Scientific	O
,	O
at	O
,	O
and	O
used	O
a	O
larger	O
PP3	B-Algorithm
battery	I-Algorithm
,	O
but	O
could	O
also	O
be	O
powered	O
by	O
mains	O
electricity	O
.	O
</s>
<s>
However	O
,	O
included	O
with	O
the	O
calculator	B-Application
was	O
a	O
library	O
of	O
over	O
120	O
programs	O
that	O
performed	O
common	O
operations	O
in	O
mathematics	O
,	O
geometry	O
,	O
statistics	O
,	O
finance	O
,	O
physics	O
,	O
electronics	O
,	O
engineering	O
,	O
as	O
well	O
as	O
fluid	O
mechanics	O
and	O
materials	O
science	O
.	O
</s>
<s>
The	O
"	O
C	O
"	O
key	O
performs	O
a	O
clear	O
;	O
pressing	O
it	O
sets	O
the	O
calculator	B-Application
to	O
a	O
state	O
with	O
zero	O
in	O
the	O
internal	O
registers	O
.	O
</s>
<s>
After	O
entering	O
the	O
mantissa	B-Algorithm
part	O
of	O
the	O
number	O
the	O
"	O
E	O
"	O
exponent	O
key	O
is	O
pressed	O
prior	O
to	O
entering	O
the	O
integer	O
exponent	O
of	O
the	O
number	O
.	O
</s>
<s>
Four	O
constants	O
are	O
printed	O
on	O
the	O
calculator	B-Application
case	O
for	O
easy	O
reference	O
.	O
</s>
