<s>
A	O
listing	B-Application
or	O
program	B-Application
listing	I-Application
is	O
a	O
printed	O
list	O
of	O
lines	O
of	O
computer	B-Application
code	I-Application
or	O
digital	B-General_Concept
data	I-General_Concept
(	O
in	O
human-readable	O
form	O
)	O
.	O
</s>
<s>
Listings	B-Application
are	O
commonly	O
used	O
in	O
education	O
and	O
computer-related	O
books	O
to	O
show	O
examples	O
of	O
code	O
.	O
</s>
<s>
In	O
the	O
early	O
days	O
of	O
programming	O
,	O
it	O
was	O
used	O
to	O
hand-check	O
a	O
program	B-Application
and	O
as	O
permanent	O
storage	O
.	O
</s>
<s>
It	O
was	O
also	O
common	O
in	O
1970s	O
and	O
1980s	O
computer	O
enthusiast	O
magazines	O
(	O
for	O
instance	O
Creative	B-General_Concept
Computing	I-General_Concept
)	O
and	O
books	O
like	O
BASIC	B-Application
Computer	I-Application
Games	I-Application
for	O
type-in	O
programs	O
.	O
</s>
<s>
Today	O
,	O
hard	B-General_Concept
copy	I-General_Concept
listings	B-Application
are	O
seldom	O
used	O
because	O
display	O
screens	O
can	O
present	O
more	O
lines	O
than	O
formerly	O
,	O
programs	O
tend	O
to	O
be	O
modular	O
,	O
storage	O
in	O
soft	B-General_Concept
copy	I-General_Concept
is	O
considered	O
preferable	O
to	O
hard	B-General_Concept
copy	I-General_Concept
,	O
and	O
digital	B-General_Concept
material	O
is	O
easily	O
transmitted	O
via	O
networks	O
,	O
or	O
on	O
disks	O
or	O
tapes	O
.	O
</s>
<s>
For	O
example	O
,	O
the	O
GNU	B-Application
C	I-Application
Compiler	I-Application
(	O
gcc	B-Application
)	O
will	O
produce	O
an	O
assembly	O
code	B-Application
listing	I-Application
if	O
it	O
is	O
invoked	O
with	O
the	O
command-line	O
option	O
-S	O
.	O
</s>
<s>
Listings	B-Application
of	O
computer	B-Application
programs	I-Application
are	O
still	O
important	O
in	O
US	O
patent	O
law	O
.	O
</s>
