<s>
A	O
hardware	B-Error_Name
bug	I-Error_Name
is	O
a	O
defect	O
in	O
the	O
design	O
,	O
manufacture	O
,	O
or	O
operation	O
of	O
computer	B-Architecture
hardware	I-Architecture
that	O
causes	O
incorrect	O
operation	O
.	O
</s>
<s>
It	O
is	O
the	O
counterpart	O
of	O
software	B-Error_Name
bugs	I-Error_Name
which	O
refer	O
to	O
flaws	O
in	O
the	O
code	O
which	O
operates	O
computers	O
,	O
and	O
is	O
the	O
original	O
context	O
in	O
which	O
"	O
bug	B-Error_Name
"	O
was	O
used	O
to	O
refer	O
to	O
such	O
flaws	O
.	O
</s>
<s>
Intermediate	O
between	O
hardware	B-Architecture
and	O
software	O
are	O
microcode	B-Device
and	O
firmware	B-Application
which	O
may	O
also	O
have	O
such	O
defects	O
.	O
</s>
<s>
In	O
common	O
usage	O
,	O
a	O
bug	B-Error_Name
is	O
subtly	O
different	O
from	O
a	O
"	O
glitch	B-Error_Name
"	O
which	O
may	O
be	O
more	O
transient	O
than	O
fundamental	O
,	O
and	O
somewhat	O
different	O
from	O
a	O
"	O
quirk	O
"	O
which	O
may	O
be	O
considered	O
useful	O
or	O
intrinsic	O
.	O
</s>
<s>
The	O
term	O
"	O
bug	B-Error_Name
"	O
to	O
describe	O
defects	O
has	O
been	O
a	O
part	O
of	O
engineering	O
jargon	O
since	O
the	O
1870s	O
and	O
predates	O
electronic	O
computers	O
and	O
computer	O
software	O
;	O
it	O
may	O
have	O
originally	O
been	O
used	O
in	O
hardware	B-Architecture
engineering	O
to	O
describe	O
mechanical	O
malfunctions	O
.	O
</s>
<s>
Baffle	O
Ball	O
,	O
the	O
first	O
mechanical	O
pinball	B-Application
game	O
,	O
was	O
advertised	O
as	O
being	O
"	O
free	O
of	O
bugs	B-Error_Name
"	O
in	O
1931	O
.	O
</s>
<s>
Problems	O
with	O
military	O
gear	O
during	O
World	O
War	O
II	O
were	O
referred	O
to	O
as	O
bugs	B-Error_Name
(	O
or	O
glitches	B-Error_Name
)	O
.	O
</s>
<s>
In	O
the	O
1940	O
film	O
,	O
Flight	O
Command	O
,	O
a	O
defect	O
in	O
a	O
piece	O
of	O
direction-finding	O
gear	O
is	O
called	O
a	O
"	O
bug	B-Error_Name
"	O
.	O
</s>
<s>
In	O
a	O
book	O
published	O
in	O
1942	O
,	O
Louise	O
Dickinson	O
Rich	O
,	O
speaking	O
of	O
a	O
powered	O
ice	O
cutting	O
machine	O
,	O
said	O
,	O
"	O
Ice	O
sawing	O
was	O
suspended	O
until	O
the	O
creator	O
could	O
be	O
brought	O
in	O
to	O
take	O
the	O
bugs	B-Error_Name
out	O
of	O
his	O
darling.	O
"	O
</s>
<s>
Isaac	O
Asimov	O
used	O
the	O
term	O
"	O
bug	B-Error_Name
"	O
to	O
relate	O
to	O
issues	O
with	O
a	O
robot	O
in	O
his	O
short	O
story	O
"	O
Catch	O
That	O
Rabbit	O
"	O
,	O
published	O
in	O
1944	O
.	O
</s>
<s>
The	O
term	O
"	O
bug	B-Error_Name
"	O
was	O
used	O
in	O
an	O
account	O
by	O
computer	O
pioneer	O
Grace	O
Hopper	O
,	O
who	O
publicized	O
the	O
cause	O
of	O
a	O
malfunction	O
in	O
an	O
early	O
electromechanical	O
computer	O
.	O
</s>
<s>
Hopper	O
did	O
not	O
find	O
the	O
bug	B-Error_Name
,	O
as	O
she	O
readily	O
acknowledged	O
.	O
</s>
<s>
The	O
operators	O
who	O
found	O
it	O
,	O
including	O
William	O
"	O
Bill	O
"	O
Burke	O
,	O
later	O
of	O
the	O
Naval	O
Weapons	O
Laboratory	O
,	O
Dahlgren	O
,	O
Virginia	O
,	O
were	O
familiar	O
with	O
the	O
engineering	O
term	O
and	O
amusedly	O
kept	O
the	O
insect	O
with	O
the	O
notation	O
"	O
First	O
actual	O
case	O
of	O
bug	B-Error_Name
being	O
found.	O
"	O
</s>
<s>
Sometimes	O
users	O
take	O
advantage	O
of	O
the	O
unintended	O
or	O
undocumented	O
operation	O
of	O
hardware	B-Architecture
to	O
serve	O
some	O
purpose	O
,	O
in	O
which	O
case	O
a	O
flaw	O
may	O
be	O
considered	O
a	O
feature	O
.	O
</s>
<s>
This	O
gives	O
rise	O
to	O
the	O
often	O
ironically	O
employed	O
acronym	O
INABIAF	O
,	O
"	O
It	O
's	O
Not	O
A	O
Bug	B-Error_Name
It	O
's	O
A	O
Feature	O
"	O
.	O
</s>
<s>
For	O
example	O
,	O
undocumented	O
instructions	O
,	O
known	O
as	O
illegal	O
opcodes	O
,	O
on	O
the	O
MOS	B-General_Concept
Technology	I-General_Concept
6510	I-General_Concept
of	O
the	O
Commodore	O
64	O
and	O
MOS	B-General_Concept
Technology	I-General_Concept
6502	I-General_Concept
of	O
the	O
Apple	B-Device
II	I-Device
computers	O
are	O
sometimes	O
utilized	O
.	O
</s>
<s>
Similarly	O
programmers	O
for	O
the	O
Amiga	B-Device
took	O
advantage	O
of	O
the	O
unintended	O
operation	O
of	O
its	O
coprocessors	O
to	O
produce	O
new	O
effects	O
or	O
optimizations	O
.	O
</s>
<s>
Some	O
flaws	O
in	O
hardware	B-Architecture
may	O
lead	O
to	O
security	O
vulnerabilities	O
where	O
memory	B-General_Concept
protection	I-General_Concept
or	O
other	O
features	O
fail	O
to	O
work	O
properly	O
.	O
</s>
<s>
Starting	O
in	O
2017	O
a	O
series	O
of	O
security	O
vulnerabilities	O
were	O
found	O
in	O
the	O
implementations	O
of	O
speculative	B-General_Concept
execution	I-General_Concept
on	O
common	O
processor	O
architectures	O
that	O
allowed	O
a	O
violation	O
of	O
privilege	O
level	O
.	O
</s>
<s>
The	O
Intel	B-General_Concept
Pentium	I-General_Concept
series	O
of	O
CPUs	O
had	O
two	O
well-known	O
bugs	B-Error_Name
discovered	O
after	O
it	O
was	O
brought	O
to	O
market	O
,	O
the	O
FDIV	B-Device
bug	I-Device
affecting	O
floating	O
point	O
division	O
which	O
resulted	O
in	O
a	O
recall	O
in	O
1994	O
,	O
and	O
the	O
F00F	B-Error_Name
bug	I-Error_Name
discovered	O
in	O
1997	O
which	O
causes	O
the	O
processor	O
to	O
stop	O
operating	O
until	O
rebooted	O
.	O
</s>
