<s>
Software	O
is	O
a	O
set	O
of	O
computer	B-Application
programs	I-Application
and	O
associated	O
documentation	O
and	O
data	B-General_Concept
.	O
</s>
<s>
This	O
is	O
in	O
contrast	O
to	O
hardware	B-Architecture
,	O
from	O
which	O
the	O
system	O
is	O
built	O
and	O
which	O
actually	O
performs	O
the	O
work	O
.	O
</s>
<s>
At	O
the	O
lowest	B-Language
programming	I-Language
level	I-Language
,	O
executable	B-Application
code	I-Application
consists	O
of	O
machine	B-Language
language	I-Language
instructions	O
supported	O
by	O
an	O
individual	O
processor	B-Architecture
—	O
typically	O
a	O
central	B-General_Concept
processing	I-General_Concept
unit	I-General_Concept
(	O
CPU	O
)	O
or	O
a	O
graphics	B-Architecture
processing	I-Architecture
unit	I-Architecture
(	O
GPU	B-Architecture
)	O
.	O
</s>
<s>
Machine	B-Language
language	I-Language
consists	O
of	O
groups	O
of	O
binary	O
values	O
signifying	O
processor	B-General_Concept
instructions	I-General_Concept
that	O
change	O
the	O
state	O
of	O
the	O
computer	O
from	O
its	O
preceding	O
state	O
.	O
</s>
<s>
For	O
example	O
,	O
an	O
instruction	O
may	O
change	O
the	O
value	O
stored	O
in	O
a	O
particular	O
storage	B-General_Concept
location	O
in	O
the	O
computer	O
—	O
an	O
effect	O
that	O
is	O
not	O
directly	O
observable	O
to	O
the	O
user	O
.	O
</s>
<s>
An	O
instruction	O
may	B-Operating_System
also	I-Operating_System
invoke	I-Operating_System
one	O
of	O
many	O
input	B-General_Concept
or	I-General_Concept
output	I-General_Concept
operations	I-General_Concept
,	O
for	O
example	O
,	O
displaying	O
some	O
text	O
on	O
a	O
computer	O
screen	O
,	O
causing	O
state	O
changes	O
that	O
should	O
be	O
visible	O
to	O
the	O
user	O
.	O
</s>
<s>
The	O
processor	B-Architecture
executes	B-General_Concept
the	O
instructions	O
in	O
the	O
order	O
they	O
are	O
provided	O
,	O
unless	O
it	O
is	O
instructed	O
to	O
"	B-General_Concept
jump	I-General_Concept
"	I-General_Concept
to	I-General_Concept
a	I-General_Concept
different	I-General_Concept
instruction	I-General_Concept
or	O
is	O
interrupted	O
by	O
the	O
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
,	O
most	O
personal	B-Device
computers	I-Device
,	O
smartphone	B-Application
devices	O
,	O
and	O
servers	B-Application
have	O
processors	B-Architecture
with	I-Architecture
multiple	I-Architecture
execution	I-Architecture
units	I-Architecture
,	O
or	O
multiple	B-Operating_System
processors	I-Operating_System
performing	I-Operating_System
computation	I-Operating_System
together	O
,	O
so	O
computing	O
has	O
become	O
a	O
much	O
more	O
concurrent	B-Architecture
activity	O
than	O
in	O
the	O
past	O
.	O
</s>
<s>
The	O
majority	O
of	O
software	O
is	O
written	O
in	O
high-level	B-Language
programming	I-Language
languages	I-Language
.	O
</s>
<s>
They	O
are	O
easier	O
and	O
more	O
efficient	O
for	O
programmers	B-Application
because	O
they	O
are	O
closer	O
to	O
natural	O
languages	O
than	O
machine	B-Language
languages	I-Language
.	O
</s>
<s>
High-level	B-Language
languages	I-Language
are	O
translated	O
into	O
machine	B-Language
language	I-Language
using	O
a	O
compiler	B-Language
,	O
an	O
interpreter	B-Application
,	O
or	O
a	O
combination	O
of	O
the	O
two	O
.	O
</s>
<s>
Software	O
may	O
also	O
be	O
written	O
in	O
a	O
low-level	B-Language
assembly	B-Language
language	I-Language
that	O
has	O
a	O
strong	O
correspondence	O
to	O
the	O
computer	O
's	O
machine	B-Language
language	I-Language
instructions	O
and	O
is	O
translated	O
into	O
machine	B-Language
language	I-Language
using	O
an	O
assembler	B-Language
.	O
</s>
<s>
An	O
algorithm	O
for	O
what	O
would	O
have	O
been	O
the	O
first	O
piece	O
of	O
software	O
was	O
written	O
by	O
Ada	B-General_Concept
Lovelace	I-General_Concept
in	O
the	O
19th	O
century	O
,	O
for	O
the	O
planned	O
Analytical	B-Device
Engine	I-Device
.	O
</s>
<s>
Because	O
of	O
the	O
proofs	O
and	O
the	O
algorithm	O
,	O
she	O
is	O
considered	O
the	O
first	O
computer	B-Application
programmer	I-Application
.	O
</s>
<s>
This	O
eventually	O
led	O
to	O
the	O
creation	O
of	O
the	O
academic	O
fields	O
of	O
computer	O
science	O
and	O
software	B-General_Concept
engineering	I-General_Concept
;	O
both	O
fields	O
study	O
software	O
and	O
its	O
creation	O
.	O
</s>
<s>
Computer	O
science	O
is	O
the	O
theoretical	O
study	O
of	O
computer	O
and	O
software	O
(	O
Turing	O
's	O
essay	O
is	O
an	O
example	O
of	O
computer	O
science	O
)	O
,	O
whereas	O
software	B-General_Concept
engineering	I-General_Concept
is	O
the	O
application	O
of	O
engineering	O
principles	O
to	O
development	O
of	O
software	B-Application
.	I-Application
</s>
<s>
In	O
2000	O
,	O
Fred	O
Shapiro	O
,	O
a	O
librarian	O
at	O
the	O
Yale	O
Law	O
School	O
,	O
published	O
a	O
letter	O
revealing	O
that	O
John	O
Wilder	O
Tukey	O
's	O
1958	O
paper	O
"	O
The	O
Teaching	O
of	O
Concrete	O
Mathematics	O
"	O
contained	O
the	O
earliest	O
known	O
usage	O
of	O
the	O
term	O
"	O
software	O
"	O
found	O
in	O
a	O
search	O
of	O
JSTOR	O
's	O
electronic	O
archives	O
,	O
predating	O
the	B-Application
Oxford	I-Application
English	I-Application
Dictionary	I-Application
's	O
citation	O
by	O
two	O
years	O
.	O
</s>
<s>
On	O
virtually	O
all	O
computer	B-Device
platforms	I-Device
,	O
software	O
can	O
be	O
grouped	O
into	O
a	O
few	O
broad	O
categories	O
.	O
</s>
<s>
Based	O
on	O
the	O
goal	O
,	O
computer	B-Application
software	I-Application
can	O
be	O
divided	O
into	O
:	O
</s>
<s>
Application	B-Application
software	I-Application
uses	O
the	O
computer	O
system	O
to	O
perform	O
special	O
functions	O
beyond	O
the	O
basic	O
operation	O
of	O
the	O
computer	O
itself	O
.	O
</s>
<s>
There	O
are	O
many	O
different	O
types	O
of	O
application	B-Application
software	I-Application
because	O
the	O
range	O
of	O
tasks	O
that	O
can	O
be	O
performed	O
with	O
a	O
modern	O
computer	O
is	O
so	O
large	O
—	O
see	O
list	O
of	O
software	B-Application
.	I-Application
</s>
<s>
System	B-Application
software	I-Application
manages	O
hardware	B-Architecture
behaviour	O
,	O
as	O
to	O
provide	O
basic	O
functionalities	O
that	O
are	O
required	O
by	O
users	O
,	O
or	O
for	O
other	O
software	O
to	O
run	O
properly	O
,	O
if	O
at	O
all	O
.	O
</s>
<s>
System	B-Application
software	I-Application
is	O
also	O
designed	O
for	O
providing	O
a	O
platform	B-Device
for	O
running	O
application	B-Application
software	I-Application
,	O
and	O
it	O
includes	O
the	O
following	O
:	O
</s>
<s>
Operating	B-General_Concept
systems	I-General_Concept
are	O
essential	O
collections	O
of	O
software	O
that	O
manage	O
resources	O
and	O
provide	O
common	O
services	O
for	O
other	O
software	O
that	O
runs	O
"	O
on	O
top	O
"	O
of	O
them	O
.	O
</s>
<s>
Supervisory	B-Operating_System
programs	I-Operating_System
,	O
boot	B-Application
loaders	I-Application
,	O
shells	B-Operating_System
and	O
window	B-Application
systems	I-Application
are	O
core	O
parts	O
of	O
operating	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
In	O
practice	O
,	O
an	O
operating	B-General_Concept
system	I-General_Concept
comes	O
bundled	O
with	O
additional	O
software	O
(	O
including	O
application	B-Application
software	I-Application
)	O
so	O
that	O
a	O
user	O
can	O
potentially	O
do	O
some	O
work	O
with	O
a	O
computer	O
that	O
only	O
has	O
one	O
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
Device	B-Application
drivers	I-Application
operate	O
or	O
control	O
a	O
particular	O
type	O
of	O
device	O
that	O
is	O
attached	O
to	O
a	O
computer	O
.	O
</s>
<s>
Each	O
device	O
needs	O
at	O
least	O
one	O
corresponding	O
device	B-Application
driver	I-Application
;	O
because	O
a	O
computer	O
typically	O
has	O
at	O
minimum	O
at	O
least	O
one	O
input	O
device	O
and	O
at	O
least	O
one	O
output	O
device	O
,	O
a	O
computer	O
typically	O
needs	O
more	O
than	O
one	O
device	B-Application
driver	I-Application
.	O
</s>
<s>
Utilities	B-Application
are	O
computer	B-Application
programs	I-Application
designed	O
to	O
assist	O
users	O
in	O
the	O
maintenance	O
and	O
care	O
of	O
their	O
computers	O
.	O
</s>
<s>
Desktop	B-Application
applications	I-Application
such	O
as	O
web	B-Application
browsers	I-Application
and	O
Microsoft	B-Application
Office	I-Application
and	O
LibreOffice	B-Application
and	O
WordPerfect	B-Application
,	O
as	O
well	O
as	O
smartphone	B-Application
and	O
tablet	B-Device
applications	O
(	O
called	O
"	O
apps	B-Application
"	O
)	O
.	O
</s>
<s>
JavaScript	B-Language
scripts	O
are	O
pieces	O
of	O
software	O
traditionally	O
embedded	O
in	O
web	O
pages	O
that	O
are	O
run	O
directly	O
inside	O
the	O
web	B-Application
browser	I-Application
when	O
a	O
web	O
page	O
is	O
loaded	O
without	O
the	O
need	O
for	O
a	O
web	B-Application
browser	I-Application
plugin	B-Application
.	O
</s>
<s>
Software	O
written	O
in	O
other	O
programming	O
languages	O
can	O
also	O
be	O
run	O
within	O
the	O
web	B-Application
browser	I-Application
if	O
the	B-Application
software	I-Application
is	O
either	O
translated	O
into	O
JavaScript	B-Language
,	O
or	O
if	O
a	O
web	B-Application
browser	I-Application
plugin	B-Application
that	O
supports	O
that	O
language	O
is	O
installed	O
;	O
the	O
most	O
common	O
example	O
of	O
the	O
latter	O
is	O
ActionScript	B-Operating_System
scripts	O
,	O
which	O
are	O
supported	O
by	O
the	O
Adobe	B-Operating_System
Flash	I-Operating_System
plugin	B-Application
.	O
</s>
<s>
Server	B-Application
software	I-Application
,	O
including	O
:	O
</s>
<s>
Web	B-Application
applications	I-Application
,	O
which	O
usually	O
run	O
on	O
the	O
web	B-Application
server	I-Application
and	O
output	O
dynamically	O
generated	O
web	O
pages	O
to	O
web	B-Application
browsers	I-Application
,	O
using	O
e.g.	O
</s>
<s>
PHP	B-Application
,	O
Java	B-Language
,	O
ASP.NET	B-Application
,	O
or	O
even	O
JavaScript	B-Language
that	I-Language
runs	I-Language
on	I-Language
the	I-Language
server	I-Language
.	O
</s>
<s>
In	O
modern	O
times	O
these	O
commonly	O
include	O
some	O
JavaScript	B-Language
to	O
be	O
run	O
in	O
the	O
web	B-Application
browser	I-Application
as	O
well	O
,	O
in	O
which	O
case	O
they	O
typically	O
run	O
partly	O
on	O
the	O
server	O
,	O
partly	O
in	O
the	O
web	B-Application
browser	I-Application
.	O
</s>
<s>
Plugins	B-Application
and	O
extensions	O
are	O
software	O
that	O
extends	O
or	O
modifies	O
the	O
functionality	O
of	O
another	O
piece	O
of	O
software	O
,	O
and	O
require	O
that	O
software	O
be	O
used	O
in	O
order	O
to	O
function	O
.	O
</s>
<s>
Embedded	B-Application
software	I-Application
resides	O
as	O
firmware	B-Application
within	O
embedded	B-Architecture
systems	I-Architecture
,	O
devices	O
dedicated	O
to	O
a	O
single	O
use	O
or	O
a	O
few	O
uses	O
such	O
as	O
cars	O
and	O
televisions	O
(	O
although	O
some	O
embedded	B-Architecture
devices	I-Architecture
such	O
as	O
wireless	O
chipsets	O
can	O
themselves	O
be	O
part	O
of	O
an	O
ordinary	O
,	O
non-embedded	O
computer	O
system	O
such	O
as	O
a	O
PC	B-Device
or	O
smartphone	B-Application
)	O
.	O
</s>
<s>
In	O
the	O
embedded	B-Architecture
system	I-Architecture
context	O
there	O
is	O
sometimes	O
no	O
clear	O
distinction	O
between	O
the	O
system	B-Application
software	I-Application
and	O
the	O
application	B-Application
software	I-Application
.	O
</s>
<s>
However	O
,	O
some	O
embedded	B-Architecture
systems	I-Architecture
run	O
embedded	B-Operating_System
operating	I-Operating_System
systems	I-Operating_System
,	O
and	O
these	O
systems	O
do	O
retain	O
the	O
distinction	O
between	O
system	B-Application
software	I-Application
and	O
application	B-Application
software	I-Application
(	O
although	O
typically	O
there	O
will	O
only	O
be	O
one	O
,	O
fixed	O
application	O
which	O
is	O
always	O
run	O
)	O
.	O
</s>
<s>
Microcode	B-Device
is	O
a	O
special	O
,	O
relatively	O
obscure	O
type	O
of	O
embedded	B-Application
software	I-Application
which	O
tells	O
the	O
processor	B-Architecture
itself	O
how	O
to	O
execute	O
machine	B-Language
code	I-Language
,	O
so	O
it	O
is	O
actually	O
a	O
lower	O
level	O
than	O
machine	B-Language
code	I-Language
.	O
</s>
<s>
It	O
is	O
typically	O
proprietary	B-Application
to	O
the	O
processor	B-Architecture
manufacturer	O
,	O
and	O
any	O
necessary	O
correctional	O
microcode	B-Device
software	O
updates	O
are	O
supplied	O
by	O
them	O
to	O
users	O
(	O
which	O
is	O
much	O
cheaper	O
than	O
shipping	O
replacement	O
processor	B-Architecture
hardware	B-Architecture
)	O
.	O
</s>
<s>
Thus	O
an	O
ordinary	O
programmer	B-Application
would	O
not	O
expect	O
to	O
ever	O
have	O
to	O
deal	O
with	O
it	O
.	O
</s>
<s>
Programming	O
tools	O
are	O
also	O
software	O
in	O
the	O
form	O
of	O
programs	O
or	O
applications	O
that	O
developers	B-Application
use	O
to	O
create	O
,	O
debug	O
,	O
maintain	O
,	O
or	O
otherwise	O
support	B-General_Concept
software	B-Application
.	I-Application
</s>
<s>
These	O
tools	O
may	O
be	O
relatively	O
self-contained	O
programs	O
such	O
as	O
compilers	B-Language
,	O
debuggers	B-Application
,	O
interpreters	B-Application
,	O
linkers	B-Application
,	O
and	O
text	B-Application
editors	I-Application
,	O
that	O
can	O
be	O
combined	O
to	O
accomplish	O
a	O
task	O
;	O
or	O
they	O
may	O
form	O
an	O
integrated	B-Application
development	I-Application
environment	I-Application
(	O
IDE	O
)	O
,	O
which	O
combines	O
much	O
or	O
all	O
of	O
the	O
functionality	O
of	O
such	O
self-contained	O
tools	O
.	O
</s>
<s>
People	O
who	O
use	O
modern	O
general	O
purpose	O
computers	O
(	O
as	O
opposed	O
to	O
embedded	B-Architecture
systems	I-Architecture
,	O
analog	O
computers	O
and	O
supercomputers	B-Architecture
)	O
usually	O
see	O
three	O
layers	O
of	O
software	O
performing	O
a	O
variety	O
of	O
tasks	O
:	O
platform	B-Device
,	O
application	O
,	O
and	O
user	O
software	B-Application
.	I-Application
</s>
<s>
Platform	B-Device
software	O
:	O
The	O
platform	B-Device
includes	O
the	O
firmware	B-Application
,	O
device	B-Application
drivers	I-Application
,	O
an	O
operating	B-General_Concept
system	I-General_Concept
,	O
and	O
typically	O
a	O
graphical	B-Application
user	I-Application
interface	I-Application
which	O
,	O
in	O
total	O
,	O
allow	O
a	O
user	O
to	O
interact	O
with	O
the	O
computer	O
and	O
its	O
peripherals	O
(	O
associated	O
equipment	O
)	O
.	O
</s>
<s>
Platform	B-Device
software	O
often	O
comes	O
bundled	O
with	O
the	O
computer	O
.	O
</s>
<s>
On	O
a	O
PC	B-Device
one	O
will	O
usually	O
have	O
the	O
ability	O
to	O
change	O
the	O
platform	B-Device
software	B-Application
.	I-Application
</s>
<s>
Application	B-Application
software	I-Application
:	O
Application	B-Application
software	I-Application
is	O
what	O
most	O
people	O
think	O
of	O
when	O
they	O
think	O
of	O
software	B-Application
.	I-Application
</s>
<s>
Application	B-Application
software	I-Application
is	O
often	O
purchased	O
separately	O
from	O
computer	B-Architecture
hardware	I-Architecture
.	O
</s>
<s>
Applications	O
are	O
usually	O
independent	O
programs	O
from	O
the	O
operating	B-General_Concept
system	I-General_Concept
,	O
though	O
they	O
are	O
often	O
tailored	O
for	O
specific	O
platforms	B-Device
.	O
</s>
<s>
Most	O
users	O
think	O
of	O
compilers	B-Language
,	O
databases	O
,	O
and	O
other	O
"	O
system	B-Application
software	I-Application
"	O
as	O
applications	O
.	O
</s>
<s>
User	O
software	O
includes	O
spreadsheet	O
templates	O
and	O
word	B-General_Concept
processor	I-General_Concept
templates	O
.	O
</s>
<s>
Even	O
email	O
filters	O
are	O
a	O
kind	O
of	O
user	O
software	B-Application
.	I-Application
</s>
<s>
Depending	O
on	O
how	O
competently	O
the	O
user-written	O
software	O
has	O
been	O
integrated	O
into	O
default	O
application	B-Application
packages	I-Application
,	O
many	O
users	O
may	O
not	O
be	O
aware	O
of	O
the	O
distinction	O
between	O
the	O
original	O
packages	O
,	O
and	O
what	O
has	O
been	O
added	O
by	O
co-workers	O
.	O
</s>
<s>
Computer	B-Application
software	I-Application
has	O
to	O
be	O
"	O
loaded	O
"	O
into	O
the	O
computer	O
's	O
storage	B-General_Concept
(	O
such	O
as	O
the	O
hard	B-Device
drive	I-Device
or	O
memory	B-General_Concept
)	O
.	O
</s>
<s>
Once	O
the	B-Application
software	I-Application
has	O
loaded	O
,	O
the	O
computer	O
is	O
able	O
to	O
execute	O
the	B-Application
software	I-Application
.	O
</s>
<s>
This	O
involves	O
passing	O
instructions	O
from	O
the	O
application	B-Application
software	I-Application
,	O
through	O
the	O
system	B-Application
software	I-Application
,	O
to	O
the	O
hardware	B-Architecture
which	O
ultimately	O
receives	O
the	O
instruction	O
as	O
machine	B-Language
code	I-Language
.	O
</s>
<s>
Each	O
instruction	O
causes	O
the	O
computer	O
to	O
carry	O
out	O
an	O
operation	O
—	O
moving	O
data	B-General_Concept
,	O
carrying	O
out	O
a	O
computation	O
,	O
or	O
altering	O
the	O
control	O
flow	O
of	O
instructions	O
.	O
</s>
<s>
Data	B-General_Concept
movement	O
is	O
typically	O
from	O
one	O
place	O
in	O
memory	B-General_Concept
to	O
another	O
.	O
</s>
<s>
Sometimes	O
it	O
involves	O
moving	O
data	B-General_Concept
between	O
memory	B-General_Concept
and	O
registers	O
which	O
enable	O
high-speed	O
data	B-General_Concept
access	O
in	O
the	O
CPU	O
.	O
</s>
<s>
Moving	O
data	B-General_Concept
,	O
especially	O
large	O
amounts	O
of	O
it	O
,	O
can	O
be	O
costly	O
;	O
this	O
is	O
sometimes	O
avoided	O
by	O
using	O
"	O
pointers	O
"	O
to	O
data	B-General_Concept
instead	O
.	O
</s>
<s>
Computations	O
include	O
simple	O
operations	O
such	O
as	O
incrementing	O
the	O
value	O
of	O
a	O
variable	O
data	B-General_Concept
element	O
.	O
</s>
<s>
More	O
complex	O
computations	O
may	O
involve	O
many	O
operations	O
and	O
data	B-General_Concept
elements	O
together	O
.	O
</s>
<s>
Software	O
quality	O
is	O
very	O
important	O
,	O
especially	O
for	O
commercial	B-Application
and	O
system	B-Application
software	I-Application
.	O
</s>
<s>
Faults	O
and	O
errors	O
are	O
called	O
"	O
bugs	B-Error_Name
"	O
which	O
are	O
often	O
discovered	O
during	O
alpha	O
and	O
beta	O
testing	O
.	O
</s>
<s>
Software	O
is	O
often	O
also	O
a	O
victim	O
to	O
what	O
is	O
known	O
as	O
software	B-General_Concept
aging	I-General_Concept
,	O
the	O
progressive	O
performance	O
degradation	O
resulting	O
from	O
a	O
combination	O
of	O
unseen	O
bugs	B-Error_Name
.	O
</s>
<s>
Many	O
bugs	B-Error_Name
are	O
discovered	O
and	O
fixed	O
through	O
software	O
testing	O
.	O
</s>
<s>
However	O
,	O
software	O
testing	O
rarely	O
—	O
if	O
ever	O
—	O
eliminates	O
every	O
bug	B-Error_Name
;	O
some	O
programmers	B-Application
say	O
that	O
"	O
every	O
program	O
has	O
at	O
least	O
one	O
more	O
bug	B-Error_Name
"	O
(	O
Lubarsky	O
's	O
Law	O
)	O
.	O
</s>
<s>
In	O
the	O
waterfall	O
method	O
of	O
software	O
development	O
,	O
separate	O
testing	O
teams	O
are	O
typically	O
employed	O
,	O
but	O
in	O
newer	O
approaches	O
,	O
collectively	O
termed	O
agile	O
software	O
development	O
,	O
developers	B-Application
often	O
do	O
all	O
their	O
own	O
testing	O
,	O
and	O
demonstrate	O
the	B-Application
software	I-Application
to	O
users/clients	O
regularly	O
to	O
obtain	O
feedback	O
.	O
</s>
<s>
Programs	O
containing	O
command	O
software	O
enable	O
hardware	B-Architecture
engineering	O
and	O
system	O
operations	O
to	O
function	O
much	O
easier	O
together	O
.	O
</s>
<s>
The	B-Application
software	I-Application
's	O
license	O
gives	O
the	O
user	O
the	O
right	O
to	O
use	O
the	B-Application
software	I-Application
in	O
the	O
licensed	O
environment	O
,	O
and	O
in	O
the	O
case	O
of	O
free	B-License
software	I-License
licenses	I-License
,	O
also	O
grants	O
other	O
rights	O
such	O
as	O
the	O
right	O
to	O
make	O
copies	O
.	O
</s>
<s>
Proprietary	B-Application
software	I-Application
can	O
be	O
divided	O
into	O
two	O
types	O
:	O
</s>
<s>
freeware	B-License
,	O
which	O
includes	O
the	O
category	O
of	O
"	O
free	O
trial	O
"	O
software	O
or	O
"	O
freemium	O
"	O
software	O
(	O
in	O
the	O
past	O
,	O
the	O
term	O
shareware	B-License
was	O
often	O
used	O
for	O
free	O
trial/freemium	O
software	O
)	O
.	O
</s>
<s>
As	O
the	O
name	O
suggests	O
,	O
freeware	B-License
can	O
be	O
used	O
for	O
free	O
,	O
although	O
in	O
the	O
case	O
of	O
free	O
trials	O
or	O
freemium	O
software	O
,	O
this	O
is	O
sometimes	O
only	O
true	O
for	O
a	O
limited	O
period	O
of	O
time	O
or	O
with	O
limited	O
functionality	O
.	O
</s>
<s>
Open-source	B-Application
software	I-Application
comes	O
with	O
a	O
free	B-License
software	I-License
license	I-License
,	O
granting	O
the	O
recipient	O
the	O
rights	O
to	O
modify	O
and	O
redistribute	O
the	B-Application
software	I-Application
.	O
</s>
<s>
an	O
algorithm	O
)	O
on	O
how	O
to	O
implement	O
a	O
piece	O
of	O
software	O
,	O
or	O
a	O
component	O
of	O
a	O
piece	O
of	O
software	B-Application
.	I-Application
</s>
<s>
Meanwhile	O
,	O
American	O
copyright	O
law	O
was	O
applied	O
to	O
various	O
aspects	O
of	O
the	O
writing	O
of	O
the	B-Application
software	I-Application
code	O
.	O
</s>
<s>
Software	O
patents	O
are	O
controversial	O
in	O
the	B-Application
software	I-Application
industry	O
with	O
many	O
people	O
holding	O
different	O
views	O
about	O
them	O
.	O
</s>
<s>
One	O
of	O
the	O
sources	O
of	O
controversy	O
is	O
that	O
the	O
aforementioned	O
split	O
between	O
initial	O
ideas	O
and	O
patent	O
does	O
not	O
seem	O
to	O
be	O
honored	O
in	O
practice	O
by	O
patent	O
lawyers	O
—	O
for	O
example	O
the	O
patent	O
for	O
aspect-oriented	B-Architecture
programming	I-Architecture
(	O
AOP	O
)	O
,	O
which	O
purported	O
to	O
claim	O
rights	O
over	O
any	O
programming	O
tool	O
implementing	O
the	O
idea	O
of	O
AOP	O
,	O
howsoever	O
implemented	O
.	O
</s>
<s>
Design	O
and	O
implementation	O
of	O
software	O
vary	O
depending	O
on	O
the	O
complexity	O
of	O
the	B-Application
software	I-Application
.	O
</s>
<s>
For	O
instance	O
,	O
the	O
design	O
and	O
creation	O
of	O
Microsoft	B-Application
Word	I-Application
took	O
much	O
more	O
time	O
than	O
designing	O
and	O
developing	O
Microsoft	B-Application
Notepad	I-Application
because	O
the	O
former	O
has	O
much	O
more	O
basic	O
functionality	O
.	O
</s>
<s>
Software	O
is	O
usually	O
developed	O
in	O
integrated	B-Application
development	I-Application
environments	I-Application
(	O
IDE	O
)	O
like	O
Eclipse	B-Application
,	O
IntelliJ	B-Language
and	O
Microsoft	B-Application
Visual	I-Application
Studio	I-Application
that	O
can	O
simplify	O
the	O
process	O
and	O
compile	B-Language
the	B-Application
software	I-Application
.	O
</s>
<s>
As	O
noted	O
in	O
a	O
different	O
section	O
,	O
software	O
is	O
usually	O
created	O
on	O
top	O
of	O
existing	O
software	O
and	O
the	O
application	B-Application
programming	I-Application
interface	I-Application
(	O
API	B-Application
)	O
that	O
the	O
underlying	O
software	O
provides	O
like	O
GTK+	B-Application
,	O
JavaBeans	O
or	O
Swing	B-Language
.	O
</s>
<s>
Libraries	O
(	O
APIs	B-Application
)	O
can	O
be	O
categorized	O
by	O
their	O
purpose	O
.	O
</s>
<s>
For	O
instance	O
,	O
the	B-Application
Spring	I-Application
Framework	I-Application
is	O
used	O
for	O
implementing	O
enterprise	B-Application
applications	I-Application
,	O
the	O
Windows	B-Application
Forms	I-Application
library	O
is	O
used	O
for	O
designing	O
graphical	B-Application
user	I-Application
interface	I-Application
(	O
GUI	B-Application
)	O
applications	O
like	O
Microsoft	B-Application
Word	I-Application
,	O
and	O
Windows	B-Application
Communication	I-Application
Foundation	I-Application
is	O
used	O
for	O
designing	O
web	O
services	O
.	O
</s>
<s>
When	O
a	O
program	O
is	O
designed	O
,	O
it	O
relies	O
upon	O
the	O
API	B-Application
.	O
</s>
<s>
For	O
instance	O
,	O
a	O
Microsoft	O
Windows	O
desktop	B-Application
application	I-Application
might	O
call	O
API	B-Application
functions	I-Application
in	O
the	O
.NET	B-Application
Windows	B-Application
Forms	I-Application
library	O
like	O
Form1.Close( )	O
and	O
Form1.Show( )	O
to	O
close	O
or	O
open	O
the	O
application	O
.	O
</s>
<s>
Without	O
these	O
APIs	B-Application
,	O
the	O
programmer	B-Application
needs	O
to	O
write	O
these	O
functionalities	O
entirely	O
themselves	O
.	O
</s>
<s>
Companies	O
like	O
Oracle	B-Application
and	O
Microsoft	O
provide	O
their	O
own	O
APIs	B-Application
so	O
that	O
many	O
applications	O
are	O
written	O
using	O
their	O
software	B-Library
libraries	I-Library
that	O
usually	O
have	O
numerous	O
APIs	B-Application
in	O
them	O
.	O
</s>
<s>
Data	B-General_Concept
structures	I-General_Concept
such	O
as	O
hash	B-Algorithm
tables	I-Algorithm
,	O
arrays	O
,	O
and	O
binary	O
trees	O
,	O
and	O
algorithms	O
such	O
as	O
quicksort	B-Algorithm
,	O
can	O
be	O
useful	O
for	O
creating	O
software	B-Application
.	I-Application
</s>
<s>
Computer	B-Application
software	I-Application
has	O
special	O
economic	O
characteristics	O
that	O
make	O
its	O
design	O
,	O
creation	O
,	O
and	O
distribution	O
different	O
from	O
most	O
other	O
economic	O
goods	O
.	O
</s>
<s>
A	O
person	O
who	O
creates	O
software	O
is	O
called	O
a	O
programmer	B-Application
,	O
software	B-General_Concept
engineer	I-General_Concept
or	O
software	B-Application
developer	I-Application
,	O
terms	O
that	O
all	O
have	O
a	O
similar	O
meaning	O
.	O
</s>
<s>
More	O
informal	O
terms	O
for	O
programmer	B-Application
also	O
exist	O
such	O
as	O
"	O
coder	B-Application
"	O
and	O
"	O
hacker	O
"	O
although	O
use	O
of	O
the	O
latter	O
word	O
may	O
cause	O
confusion	O
,	O
because	O
it	O
is	O
more	O
often	O
used	O
to	O
mean	O
someone	O
who	O
illegally	O
breaks	O
into	O
computer	O
systems	O
.	O
</s>
