<s>
Bit-level	B-Operating_System
parallelism	I-Operating_System
is	O
a	O
form	O
of	O
parallel	B-Operating_System
computing	I-Operating_System
based	O
on	O
increasing	O
processor	O
word	O
size	O
.	O
</s>
<s>
(	O
For	O
example	O
,	O
consider	O
a	O
case	O
where	O
an	O
8-bit	O
processor	O
must	O
add	O
two	O
16-bit	B-Device
integers	O
.	O
</s>
<s>
A	O
16-bit	B-Device
processor	I-Device
would	O
be	O
able	O
to	O
complete	O
the	O
operation	O
with	O
single	O
instruction	O
.	O
)	O
</s>
<s>
The	O
first	O
electronic	O
computer	O
that	O
was	O
not	O
a	O
serial	B-Device
computer	I-Device
—	O
the	O
first	O
bit-parallel	O
computer	O
—	O
was	O
the	O
16-bit	B-Device
Whirlwind	B-Device
from	O
1951	O
.	O
</s>
<s>
From	O
the	O
advent	O
of	O
very-large-scale	O
integration	O
(	O
VLSI	O
)	O
computer	O
chip	O
fabrication	O
technology	O
in	O
the	O
1970s	O
until	O
about	O
1986	O
,	O
advancements	O
in	O
computer	O
architecture	O
were	O
done	O
by	O
increasing	O
bit-level	B-Operating_System
parallelism	I-Operating_System
,	O
as	O
4-bit	O
microprocessors	O
were	O
replaced	O
by	O
8-bit	O
,	O
then	O
16-bit	B-Device
,	O
then	O
32-bit	O
microprocessors	O
.	O
</s>
<s>
64	O
bit	O
architectures	O
were	O
introduced	O
to	O
the	O
mainstream	O
with	O
the	O
eponymous	O
Nintendo	O
64	O
(	O
1996	O
)	O
,	O
but	O
beyond	O
this	O
introduction	O
stayed	O
uncommon	O
until	O
the	O
advent	O
of	O
x86-64	B-Device
architectures	O
around	O
the	O
year	O
2003	O
,	O
and	O
2014	O
for	O
mobile	O
devices	O
with	O
the	O
ARMv8-A	O
instruction	O
set	O
.	O
</s>
<s>
On	O
32-bit	O
processors	O
,	O
external	B-General_Concept
data	I-General_Concept
bus	I-General_Concept
width	O
continues	O
to	O
increase	O
.	O
</s>
