<s>
A	O
free-software	B-License
license	I-License
is	O
a	O
notice	O
that	O
grants	O
the	O
recipient	O
of	O
a	O
piece	O
of	O
software	O
extensive	O
rights	O
to	O
modify	O
and	O
redistribute	B-Application
that	O
software	O
.	O
</s>
<s>
These	O
actions	O
are	O
usually	O
prohibited	O
by	O
copyright	O
law	O
,	O
but	O
the	O
rights-holder	O
(	O
usually	O
the	O
author	O
)	O
of	O
a	O
piece	O
of	O
software	O
can	O
remove	O
these	O
restrictions	O
by	O
accompanying	O
the	O
software	O
with	O
a	O
software	B-License
license	I-License
which	O
grants	O
the	O
recipient	O
these	O
rights	O
.	O
</s>
<s>
Software	O
using	O
such	O
a	O
license	O
is	O
free	O
software	O
(	O
or	O
free	B-License
and	I-License
open-source	I-License
software	I-License
)	O
as	O
conferred	O
by	O
the	O
copyright	O
holder	O
.	O
</s>
<s>
Free-software	B-License
licenses	I-License
are	O
applied	O
to	O
software	O
in	O
source	O
code	O
and	O
also	O
binary	O
object-code	B-Language
form	O
,	O
as	O
the	O
copyright	O
law	O
recognizes	O
both	O
forms	O
.	O
</s>
<s>
Types	O
of	O
software	B-License
license	I-License
and	O
similar	O
licenses	O
.	O
</s>
<s>
Public	O
domain	O
&	O
equivalents	O
Permissive	B-License
license	I-License
Copyleft	B-License
(	O
protective	O
license	O
)	O
Noncommercial	O
license	O
Proprietary	B-Application
license	I-Application
Trade	O
secret	O
Description	O
Grants	O
all	O
rights	O
Grants	O
use	O
rights	O
,	O
including	O
right	O
to	O
relicense	O
(	O
allows	O
proprietization	B-Application
,	O
license	O
compatibility	O
)	O
Grants	O
use	O
rights	O
,	O
forbids	O
proprietization	B-Application
Grants	O
rights	O
for	O
noncommercial	O
use	O
only	O
.	O
</s>
<s>
May	O
be	O
combined	O
with	O
copyleft	B-License
.	O
</s>
<s>
Free-software	B-License
licenses	I-License
provide	O
risk	O
mitigation	O
against	O
different	O
legal	O
threats	O
or	O
behaviors	O
that	O
are	O
seen	O
as	O
potentially	O
harmful	O
by	O
developers	O
:	O
</s>
<s>
Therefore	O
,	O
software	O
had	O
no	O
licenses	O
attached	O
and	O
was	O
shared	O
as	O
public-domain	B-Application
software	I-Application
.	O
</s>
<s>
The	O
CONTU	O
decision	O
plus	O
court	O
decisions	O
such	O
as	O
Apple	B-Device
v	I-Device
.	I-Device
Franklin	I-Device
in	O
1983	O
for	O
object	B-Language
code	I-Language
,	O
clarified	O
that	O
the	O
Copyright	O
Act	O
gave	O
computer	O
programs	O
the	O
copyright	O
status	O
of	O
literary	O
works	O
and	O
started	O
the	O
licensing	B-License
of	I-License
software	I-License
.	O
</s>
<s>
Free-software	B-License
licenses	I-License
before	O
the	O
late	O
1980s	O
were	O
generally	O
informal	O
notices	O
written	O
by	O
the	O
developers	O
themselves	O
.	O
</s>
<s>
These	O
early	O
licenses	O
were	O
of	O
the	O
"	O
permissive	B-License
"	O
kind	O
.	O
</s>
<s>
In	O
the	O
mid-1980s	O
,	O
the	B-Application
GNU	I-Application
project	I-Application
produced	O
copyleft	B-License
free-software	B-License
licenses	I-License
for	O
each	O
of	O
its	O
software	O
packages	O
.	O
</s>
<s>
An	O
early	O
such	O
license	O
(	O
the	O
"	O
GNU	B-Application
Emacs	I-Application
Copying	O
Permission	O
Notice	O
"	O
)	O
was	O
used	O
for	O
GNU	B-Application
Emacs	I-Application
in	O
1985	O
,	O
which	O
was	O
revised	O
into	O
the	O
"	O
GNU	B-Application
Emacs	I-Application
General	B-License
Public	I-License
License	I-License
"	O
in	O
late	O
1985	O
,	O
and	O
clarified	O
in	O
March	O
1987	O
and	O
February	O
1988	O
.	O
</s>
<s>
Likewise	O
,	O
the	O
similar	O
GCC	B-Application
General	B-License
Public	I-License
License	I-License
was	O
applied	O
to	O
the	O
GNU	B-Application
Compiler	I-Application
Collection	I-Application
,	O
which	O
was	O
initially	O
published	O
in	O
1987	O
.	O
</s>
<s>
The	O
original	B-License
BSD	I-License
license	I-License
is	O
also	O
one	O
of	O
the	O
first	O
free-software	B-License
licenses	I-License
,	O
dating	O
to	O
1988	O
.	O
</s>
<s>
In	O
1989	O
,	O
version1	O
of	O
the	O
GNU	B-License
General	I-License
Public	I-License
License	I-License
(	O
GPL	B-License
)	O
was	O
published	O
.	O
</s>
<s>
Version2	O
of	O
the	O
GPL	B-License
,	O
released	O
in	O
1991	O
,	O
went	O
on	O
to	O
become	O
the	O
most	O
widely	O
used	O
free-software	B-License
license	I-License
.	O
</s>
<s>
Starting	O
in	O
the	O
mid-1990s	O
and	O
until	O
the	O
mid-2000s	O
,	O
the	O
open-source	B-Application
movement	O
pushed	O
and	O
focused	O
the	O
free-software	O
idea	O
forward	O
in	O
the	O
wider	O
public	O
and	O
business	O
perception	O
.	O
</s>
<s>
In	O
the	O
Dot-com	O
bubble	O
time	O
,	O
Netscape	O
Communications	O
 '	O
step	O
to	O
release	O
its	O
webbrowser	O
under	O
a	O
FOSS	B-License
license	O
in	O
1998	O
,	O
inspired	O
many	O
other	O
companies	O
to	O
adapt	O
to	O
the	O
FOSS	B-License
ecosystem	O
.	O
</s>
<s>
In	O
this	O
trend	O
companies	O
and	O
new	O
projects	O
(	O
Mozilla	B-Operating_System
,	O
Apache	B-Application
foundation	O
,	O
and	O
Sun	O
,	O
see	O
also	O
this	B-Application
list	I-Application
)	O
wrote	O
their	O
own	O
FOSS	B-License
licenses	O
,	O
or	O
adapted	O
existing	O
licenses	O
.	O
</s>
<s>
This	O
License	B-License
proliferation	I-License
was	O
later	O
recognized	O
as	O
problem	O
for	O
the	O
Free	B-License
and	I-License
open-source	I-License
ecosystem	O
due	O
to	O
the	O
increased	O
complexity	O
of	O
license	O
compatibility	O
considerations	O
.	O
</s>
<s>
While	O
the	O
creation	O
of	O
new	O
licenses	O
slowed	O
down	O
later	O
,	O
license	B-License
proliferation	I-License
and	O
its	O
impact	O
are	O
considered	O
an	O
ongoing	O
serious	O
challenge	O
for	O
the	O
free	B-License
and	I-License
open-source	I-License
ecosystem	O
.	O
</s>
<s>
From	O
the	O
free-software	B-License
licenses	I-License
,	O
the	O
GNU	B-License
GPL	I-License
version2	O
has	O
been	O
tested	O
in	O
to	O
court	O
,	O
first	O
in	O
Germany	O
in	O
2004	O
and	O
later	O
in	O
the	O
USA	O
.	O
</s>
<s>
In	O
the	O
German	O
case	O
the	O
judge	O
did	O
not	O
explicitly	O
discuss	O
the	O
validity	O
of	O
the	O
GPL	B-License
's	O
clauses	O
but	O
accepted	O
that	O
the	O
GPL	B-License
had	O
to	O
be	O
adhered	O
to	O
:	O
"	O
If	O
the	O
GPL	B-License
were	O
not	O
agreed	O
upon	O
by	O
the	O
parties	O
,	O
defendant	O
would	O
notwithstanding	O
lack	O
the	O
necessary	O
rights	O
to	O
copy	O
,	O
distribute	O
,	O
and	O
make	O
the	O
software	O
'	O
netfilter/iptables	O
'	O
publicly	O
available.	O
"	O
</s>
<s>
Because	O
the	O
defendant	O
did	O
not	O
comply	O
with	O
the	O
GPL	B-License
,	O
it	O
had	O
to	O
cease	O
use	O
of	O
the	O
software	O
.	O
</s>
<s>
The	O
US	O
case	O
(	O
MySQL	B-Application
vs	O
Progress	O
)	O
was	O
settled	O
before	O
a	O
verdict	O
was	O
arrived	O
at	O
,	O
but	O
at	O
an	O
initial	O
hearing	O
,	O
Judge	O
Saris	O
"	O
saw	O
no	O
reason	O
"	O
that	O
the	O
GPL	B-License
would	O
not	O
be	O
enforceable	O
.	O
</s>
<s>
Around	O
2004	O
lawyer	O
Lawrence	O
Rosen	O
argued	O
in	O
the	O
essay	O
Why	O
the	O
public	O
domain	O
is	O
n't	O
a	O
license	O
software	O
could	O
not	O
truly	O
be	O
waived	O
into	O
public	O
domain	O
and	O
ca	O
n't	O
be	O
interpreted	O
as	O
very	O
permissive	B-License
FOSS	I-License
license	I-License
,	O
a	O
position	O
which	O
faced	O
opposition	O
by	O
Daniel	O
J	O
.	O
Bernstein	O
and	O
others	O
.	O
</s>
<s>
Several	O
major	O
FOSS	B-License
projects	O
(	O
Linux	B-Operating_System
kernel	I-Operating_System
,	O
MySQL	B-Application
,	O
BusyBox	B-Application
,	O
Blender	B-Application
,	O
VLC	B-Application
media	I-Application
player	I-Application
)	O
decided	O
against	O
adopting	O
the	O
GPLv3	O
.	O
</s>
<s>
On	O
the	O
other	O
hand	O
,	O
in	O
2009	O
,	O
two	O
years	O
after	O
the	O
release	O
of	O
the	O
GPLv3	O
,	O
Google	B-Application
open-source	B-Application
programs	I-Application
office	O
manager	O
Chris	O
DiBona	O
reported	O
that	O
the	O
number	O
of	O
open-source	B-Application
projects	O
licensed	O
software	O
that	O
had	O
moved	O
to	O
GPLv3	O
from	O
GPLv2	O
was	O
50%	O
,	O
counting	O
the	O
projects	O
hosted	O
at	O
Google	B-Protocol
Code	I-Protocol
.	O
</s>
<s>
In	O
2011	O
,	O
four	O
years	O
after	O
the	O
release	O
of	O
the	O
GPLv3	O
,	O
6.5	O
%	O
of	O
all	O
open-source	B-Application
licensed	O
projects	O
were	O
GPLv3	O
while	O
42.5	O
%	O
were	O
still	O
GPLv2	O
according	O
to	O
Black	O
Duck	O
Software	O
data	O
.	O
</s>
<s>
Following	O
in	O
2011	O
451	O
Group	O
analyst	O
Matthew	O
Aslett	O
argued	O
in	O
a	O
blog	O
post	O
that	O
copyleft	B-License
licenses	I-License
went	O
into	O
decline	O
and	O
permissive	B-License
licenses	I-License
increased	O
,	O
based	O
on	O
statistics	O
from	O
Black	O
Duck	O
Software	O
.	O
</s>
<s>
In	O
2015	O
according	O
to	O
Black	O
Duck	O
Software	O
and	O
GitHub	B-Application
statistics	O
,	O
the	O
permissive	B-License
MIT	B-License
license	I-License
dethroned	O
the	O
GPLv2	O
as	O
most	O
popular	O
free-software	B-License
license	I-License
to	O
the	O
second	O
place	O
while	O
the	O
permissive	B-License
Apache	B-Application
license	I-Application
follows	O
already	O
at	O
third	O
place	O
.	O
</s>
<s>
In	O
June	O
2016	O
an	O
analysis	O
of	O
Fedora	O
Project	O
's	O
packages	O
revealed	O
as	O
most	O
used	O
licenses	O
the	O
GPL	B-License
,	O
MIT	B-License
,	O
BSD	B-Operating_System
,	O
and	O
the	O
LGPL	B-Application
.	O
</s>
<s>
The	O
group	O
Open	O
Source	O
Initiative	O
(	O
OSI	O
)	O
defines	O
and	O
maintains	O
a	O
list	O
of	O
approved	O
open-source	B-Application
licenses	O
.	O
</s>
<s>
OSI	O
agrees	O
with	O
FSF	O
on	O
all	O
widely	O
used	O
free-software	B-License
licenses	I-License
,	O
but	O
differ	O
from	O
FSF	O
's	O
list	O
,	O
as	O
it	O
approves	O
against	O
the	B-License
Open	I-License
Source	I-License
Definition	I-License
rather	O
than	O
the	B-Application
Free	I-Application
Software	I-Application
Definition	I-Application
.	O
</s>
<s>
It	O
considers	O
Free	O
Software	O
Permissive	B-License
license	I-License
group	O
to	O
be	O
a	O
reference	O
implementation	O
of	O
a	O
Free	B-License
Software	I-License
license	I-License
.	O
</s>
<s>
The	B-Operating_System
Free	I-Operating_System
Software	I-Operating_System
Foundation	I-Operating_System
,	O
the	O
group	O
that	O
maintains	O
the	B-Application
Free	I-Application
Software	I-Application
Definition	I-Application
,	O
maintains	O
a	O
non-exhaustive	O
list	O
of	O
free-software	B-License
licences	I-License
.	O
</s>
<s>
The	B-Operating_System
Free	I-Operating_System
Software	I-Operating_System
Foundation	I-Operating_System
prefers	O
copyleft	B-License
(	O
share-alike	O
)	O
free-software	O
licensing	O
rather	O
than	O
permissive	B-License
free-software	O
licensing	O
for	O
most	O
purposes	O
.	O
</s>
<s>
Its	O
list	O
distinguishes	O
between	O
free-software	B-License
licenses	I-License
that	O
are	O
compatible	O
or	O
incompatible	O
with	O
the	O
FSF	O
's	O
copyleft	B-License
GNU	B-License
General	I-License
Public	I-License
License	I-License
.	O
</s>
<s>
Only	O
"	O
public-domain	B-Application
software	I-Application
"	O
and	O
software	O
under	O
a	O
public-domain-like	O
license	O
is	O
restriction-free	O
.	O
</s>
<s>
Examples	O
of	O
public-domain-like	O
licenses	O
are	O
,	O
for	O
instance	O
,	O
the	O
WTFPL	B-License
and	O
the	O
CC0	O
license	O
.	O
</s>
<s>
Permissive	B-License
licenses	I-License
might	O
carry	O
small	O
obligations	O
like	O
attribution	O
of	O
the	O
author	O
but	O
allow	O
practically	O
all	O
code	O
use	O
cases	O
.	O
</s>
<s>
Certain	O
licenses	O
,	O
namely	O
the	O
copyleft	B-License
licenses	I-License
,	O
include	O
intentionally	O
stronger	O
restrictions	O
(	O
especially	O
on	O
the	O
distribution/distributor	O
)	O
in	O
order	O
to	O
force	O
derived	O
projects	O
to	O
guarantee	O
specific	O
rights	O
which	O
ca	O
n't	O
be	O
taken	O
away	O
.	O
</s>
<s>
The	O
free-software	O
share-alike	O
licenses	O
written	O
by	O
Richard	O
Stallman	O
in	O
the	O
mid-1980s	O
pioneered	O
a	O
concept	O
known	O
as	O
"	O
copyleft	B-License
"	O
.	O
</s>
<s>
Ensuing	O
copyleft	B-License
provisions	O
stated	O
that	O
when	O
modified	O
versions	O
of	O
free	O
software	O
are	O
distributed	O
,	O
they	O
must	O
be	O
distributed	O
under	O
the	O
same	O
terms	O
as	O
the	O
original	O
software	O
.	O
</s>
<s>
Since	O
copyleft	B-License
ensures	O
that	O
later	O
generations	O
of	O
the	O
software	O
grant	O
the	O
freedom	O
to	O
modify	O
the	O
code	O
,	O
this	O
is	O
"	O
free	O
software	O
"	O
.	O
</s>
<s>
Non-copyleft	B-License
licenses	O
do	O
not	O
ensure	O
that	O
later	O
generations	O
of	O
the	O
software	O
will	O
remain	O
free	O
.	O
</s>
<s>
Developers	O
who	O
use	O
GPL	B-License
code	O
in	O
their	O
product	O
must	O
make	O
the	O
source	O
code	O
available	O
to	O
anyone	O
when	O
they	O
share	O
or	O
sell	O
the	O
object	B-Language
code	I-Language
.	O
</s>
<s>
If	O
GPL	B-License
code	O
is	O
used	O
but	O
not	O
shared	O
or	O
sold	O
,	O
the	O
code	O
is	O
not	O
required	O
to	O
be	O
made	O
available	O
and	O
any	O
changes	O
may	O
remain	O
private	O
.	O
</s>
<s>
This	O
permits	O
developers	O
and	O
organizations	O
to	O
use	O
and	O
modify	O
GPL	B-License
code	O
for	O
private	O
purposes	O
(	O
that	O
is	O
,	O
when	O
the	O
code	O
or	O
the	O
project	O
is	O
not	O
sold	O
or	O
otherwise	O
shared	O
)	O
without	O
being	O
required	O
to	O
make	O
their	O
changes	O
available	O
to	O
the	O
public	O
.	O
</s>
<s>
Supporters	O
of	O
GPL	B-License
claim	O
that	O
by	O
mandating	O
that	O
derivative	O
works	O
remain	O
under	O
the	O
GPL	B-License
,	O
it	O
fosters	O
the	O
growth	O
of	O
free	O
software	O
and	O
requires	O
equal	O
participation	O
by	O
all	O
users	O
.	O
</s>
<s>
Opponents	O
of	O
GPL	B-License
claim	O
that	O
"	O
no	O
license	O
can	O
guarantee	O
future	O
software	O
availability	O
"	O
and	O
that	O
the	O
disadvantages	O
of	O
GPL	B-License
outweigh	O
its	O
advantages	O
.	O
</s>
<s>
For	O
example	O
,	O
a	O
non-copyleft	B-License
license	O
does	O
not	O
grant	O
the	O
author	O
the	O
freedom	O
to	O
see	O
modified	O
versions	O
of	O
his	O
or	O
her	O
work	O
if	O
it	O
gets	O
publicly	O
published	O
,	O
whereas	O
a	O
copyleft	B-License
license	I-License
does	O
grant	O
that	O
freedom	O
.	O
</s>
<s>
During	O
the	O
1990s	O
,	O
free-software	B-License
licenses	I-License
began	O
including	O
clauses	O
,	O
such	O
as	O
patent	O
retaliation	O
,	O
in	O
order	O
to	O
protect	O
against	O
software	O
patent	O
litigation	O
cases	O
–	O
a	O
problem	O
which	O
had	O
not	O
previously	O
existed	O
.	O
</s>
<s>
This	O
new	O
threat	O
was	O
one	O
of	O
the	O
reasons	O
for	O
writing	O
version3	O
of	O
the	O
GNU	B-License
GPL	I-License
in	O
2006	O
.	O
</s>
<s>
In	O
recent	O
years	O
,	O
a	O
term	O
coined	O
tivoization	O
describes	O
a	O
process	O
where	O
hardware	O
restrictions	O
are	O
used	O
to	O
prevent	O
users	O
from	O
running	O
modified	O
versions	O
of	O
the	O
software	O
on	O
that	O
hardware	O
,	O
in	O
which	O
the	O
TiVo	B-Application
device	O
is	O
an	O
example	O
.	O
</s>
<s>
Most	O
newly	O
written	O
free-software	B-License
licenses	I-License
since	O
the	O
late	O
1990s	O
include	O
some	O
form	O
of	O
patent	O
retaliation	O
clauses	O
.	O
</s>
<s>
As	O
an	O
example	O
,	O
the	O
Apple	B-License
Public	I-License
Source	I-License
License	I-License
may	O
terminate	O
a	O
user	O
's	O
rights	O
if	O
said	O
user	O
embarks	O
on	O
litigation	O
proceedings	O
against	O
them	O
due	O
to	O
patent	O
litigation	O
.	O
</s>
<s>
Version3	O
of	O
the	O
GNU	B-License
GPL	I-License
includes	O
specific	O
language	O
prohibiting	O
additional	O
restrictions	O
being	O
enforced	O
by	O
hardware	O
restrictions	O
and	O
digital	O
rights	O
management	O
(	O
DRM	O
)	O
,	O
a	O
practice	O
FSF	O
calls	O
tivoization	O
after	O
Tivo	B-Application
used	O
GPL	B-License
’d	O
software	O
on	O
devices	O
that	O
disallowed	O
user	O
modification	O
of	O
that	O
software	O
.	O
</s>
<s>
The	O
majority	O
of	O
free-software	B-License
licenses	I-License
require	O
that	O
modified	O
software	O
not	O
claim	O
to	O
be	O
unmodified	O
.	O
</s>
<s>
One	O
such	O
example	O
is	O
version2	O
of	O
the	O
GNU	B-License
GPL	I-License
,	O
which	O
requires	O
that	O
interactive	O
programs	O
that	O
print	O
warranty	O
or	O
license	O
information	O
,	O
may	O
not	O
have	O
these	O
notices	O
removed	O
from	O
modified	O
versions	O
intended	O
for	O
distribution	O
.	O
</s>
<s>
License	O
compatibility	O
between	O
a	O
copyleft	B-License
license	I-License
and	O
another	O
license	O
is	O
often	O
only	O
a	O
one-way	O
compatibility	O
.	O
</s>
<s>
This	O
"	O
one-way	O
compatibility	O
"	O
characteristic	O
is	O
,	O
for	O
instanced	O
,	O
criticized	O
by	O
the	O
Apache	B-Application
Foundation	O
,	O
who	O
provides	O
the	O
more	O
permissive	B-License
Apache	B-Application
license	I-Application
which	O
does	O
n't	O
have	O
this	O
characteristic	O
.	O
</s>
<s>
Non-copyleft	B-License
licenses	O
,	O
such	O
as	O
the	O
FOSS	B-License
permissive	B-License
licenses	I-License
,	O
have	O
a	O
less	O
complicated	O
license	O
interaction	O
and	O
normally	O
exhibit	O
better	O
license	O
compatibility	O
.	O
</s>
<s>
When	O
it	O
comes	O
to	O
copyleft	B-License
software	B-License
licenses	I-License
,	O
they	O
are	O
not	O
inherently	O
compatible	O
with	O
other	O
copyleft	B-License
licenses	I-License
,	O
even	O
the	O
GPLv2	O
is	O
,	O
by	O
itself	O
,	O
not	O
compatible	O
with	O
the	O
GPLv3	O
.	O
</s>
<s>
Restrictions	O
on	O
use	O
of	O
a	O
software	O
(	O
"	O
use	O
restrictions	O
"	O
)	O
are	O
generally	O
unacceptable	O
according	O
to	O
the	O
FSF	O
,	O
OSI	O
,	O
Debian	O
,	O
or	O
the	O
BSD-based	O
distributions	O
.	O
</s>
<s>
concerning	O
nuclear	O
war	O
,	O
seem	O
to	O
enjoy	O
moral	O
support	O
among	O
most	O
free	O
software	O
developers	O
,	O
it	O
is	O
generally	O
believed	O
that	O
such	O
agendas	O
should	O
not	O
be	O
served	O
through	O
software	B-License
licenses	I-License
;	O
among	O
other	O
things	O
because	O
of	O
practical	O
aspects	O
such	O
as	O
resulting	O
legal	O
uncertainties	O
and	O
problems	O
with	O
enforceability	O
of	O
vague	O
,	O
broad	O
and/or	O
subjective	O
criteria	O
or	O
because	O
tool	O
makers	O
are	O
generally	O
not	O
held	O
responsible	O
for	O
other	O
people	O
’s	O
use	O
of	O
their	O
tools	O
.	O
</s>
<s>
Nevertheless	O
some	O
projects	O
include	O
legally	O
non-binding	O
pleas	O
to	O
the	O
user	O
,	O
prominently	O
SQLite	B-Language
.	O
</s>
<s>
Among	O
the	O
repeated	O
attempts	O
by	O
developers	O
to	O
regulate	O
user	O
behavior	O
through	O
the	O
license	O
that	O
sparked	O
wider	O
debate	O
are	O
Douglas	O
Crockford	O
’s	O
(	O
joking	O
)	O
“	O
no	O
evil	O
”	O
clause	O
,	O
which	O
affected	O
the	O
release	O
process	O
of	O
the	O
Debian	O
distribution	O
in	O
2012	O
and	O
got	O
the	O
JSMin-PHP	O
project	O
expelled	O
from	O
Google	B-Protocol
Code	I-Protocol
,	O
the	O
addition	O
of	O
a	O
pacifist	O
condition	O
based	O
on	O
Asimov	O
’s	O
First	O
Law	O
of	O
Robotics	O
to	O
the	O
GPL	B-License
for	O
the	O
distributed	O
computing	O
software	O
GPU	O
in	O
2005	O
,	O
as	O
well	O
as	O
several	O
software	O
projects	O
trying	O
to	O
exclude	O
use	O
by	O
big	O
cloud	O
providers	O
.	O
</s>
<s>
As	O
there	O
are	O
several	O
defining	O
organizations	O
and	O
groups	O
who	O
publish	O
definitions	O
and	O
guidelines	O
about	O
FOSS	B-License
licenses	O
,	O
notably	O
the	O
FSF	O
,	O
the	O
OSI	O
,	O
the	O
Debian	O
project	O
,	O
and	O
the	O
BSDs	B-Operating_System
,	O
there	O
are	O
sometimes	O
conflicting	O
opinions	O
and	O
interpretations	O
.	O
</s>
<s>
Many	O
users	O
and	O
developers	O
of	O
BSD-based	O
operating	O
systems	O
have	O
a	O
different	O
position	O
on	O
licensing	O
.	O
</s>
<s>
The	O
main	O
difference	O
is	O
the	O
belief	O
that	O
the	O
copyleft	B-License
licenses	I-License
,	O
particularly	O
the	O
GNU	B-License
General	I-License
Public	I-License
License	I-License
(	O
GPL	B-License
)	O
,	O
are	O
undesirably	O
complicated	O
and/or	O
restrictive	O
.	O
</s>
<s>
The	O
GPL	B-License
requires	O
any	O
derivative	O
work	O
to	O
also	O
be	O
released	O
according	O
to	O
the	O
GPL	B-License
while	O
the	O
BSD	B-Operating_System
license	I-Operating_System
does	O
not	O
.	O
</s>
<s>
Essentially	O
,	O
the	O
BSD	B-Operating_System
license	I-Operating_System
's	O
only	O
requirement	O
is	O
to	O
acknowledge	O
the	O
original	O
authors	O
,	O
and	O
poses	O
no	O
restrictions	O
on	O
how	O
the	O
source	O
code	O
may	O
be	O
used	O
.	O
</s>
<s>
As	O
a	O
result	O
,	O
BSD	B-Operating_System
code	O
can	O
be	O
used	O
in	O
proprietary	B-Application
software	I-Application
that	O
only	O
acknowledges	O
the	O
authors	O
.	O
</s>
<s>
For	O
instance	O
,	O
Microsoft	B-Device
Windows	I-Device
NT	I-Device
3.1	I-Device
and	O
macOS	B-Application
have	O
proprietary	B-Application
IP	B-Protocol
stacks	I-Protocol
which	O
are	O
derived	O
from	O
BSD-licensed	O
software	O
.	O
</s>
<s>
In	O
extreme	O
cases	O
,	O
the	O
sub	O
-	O
or	O
re-licensing	O
possibilities	O
with	O
BSD	B-Operating_System
or	O
other	O
permissive	B-License
licenses	I-License
might	O
prevent	O
further	O
use	O
in	O
the	O
open-source	B-Application
ecosystem	O
.	O
</s>
<s>
For	O
instance	O
,	O
MathWorks	O
 '	O
FileExchange	O
repository	O
offers	O
the	O
BSD	B-Operating_System
license	I-Operating_System
for	O
user	O
contributions	O
but	O
prevents	O
with	O
additional	O
terms	O
of	O
use	O
any	O
usage	O
beside	O
their	O
own	O
proprietary	B-Application
MATLAB	B-Language
software	I-Language
,	O
for	O
instance	O
with	O
the	O
FOSS	B-License
GNU	B-Language
Octave	I-Language
software	O
.	O
</s>
<s>
Supporters	O
of	O
the	O
BSD	B-Operating_System
license	I-Operating_System
argue	O
that	O
it	O
is	O
more	O
free	O
than	O
the	O
GPL	B-License
because	O
it	O
grants	O
the	O
right	O
to	O
do	O
anything	O
with	O
the	O
source	O
code	O
,	O
provided	O
that	O
the	O
attribution	O
is	O
preserved	O
.	O
</s>
<s>
The	O
approach	O
has	O
led	O
to	O
BSD	B-Operating_System
code	O
being	O
used	O
in	O
widely	O
used	O
proprietary	B-Application
software	I-Application
.	O
</s>
<s>
Proponents	O
of	O
the	O
GPL	B-License
point	O
out	O
that	O
once	O
code	O
becomes	O
proprietary	B-Application
,	O
users	O
are	O
denied	O
the	O
freedoms	O
that	O
define	O
free	O
software	O
.	O
</s>
<s>
As	O
a	O
result	O
,	O
they	O
consider	O
the	O
BSD	B-Operating_System
license	I-Operating_System
less	O
free	O
than	O
the	O
GPL	B-License
,	O
and	O
that	O
freedom	O
is	O
more	O
than	O
a	O
lack	O
of	O
restriction	O
.	O
</s>
<s>
Since	O
the	O
BSD	B-Operating_System
license	I-Operating_System
restricts	O
the	O
right	O
of	O
developers	O
to	O
have	O
changes	O
recontributed	O
to	O
the	O
community	O
,	O
neither	O
it	O
nor	O
the	O
GPL	B-License
is	O
"	O
free	O
"	O
in	O
the	O
sense	O
of	O
"	O
lacking	O
any	O
restrictions.	O
"	O
</s>
<s>
The	O
Debian	O
project	O
uses	O
the	O
criteria	O
laid	O
out	O
in	O
its	O
Debian	B-License
Free	I-License
Software	I-License
Guidelines	I-License
(	O
DFSG	B-License
)	O
.	O
</s>
<s>
The	O
only	O
notable	O
cases	O
where	O
Debian	O
and	O
Free	B-Operating_System
Software	I-Operating_System
Foundation	I-Operating_System
disagree	O
are	O
over	O
the	O
Artistic	B-License
License	I-License
and	O
the	O
GNU	B-Application
Free	I-Application
Documentation	I-Application
License	I-Application
(	O
GFDL	B-Application
)	O
.	O
</s>
<s>
Debian	O
accepts	O
the	O
original	O
Artistic	B-License
License	I-License
as	O
being	O
a	O
free	B-License
software	I-License
license	I-License
,	O
but	O
FSF	O
disagrees	O
.	O
</s>
<s>
This	O
has	O
very	O
little	O
impact	O
however	O
since	O
the	O
Artistic	B-License
License	I-License
is	O
almost	O
always	O
used	O
in	O
a	O
dual-license	B-License
setup	O
,	O
along	O
with	O
the	O
GNU	B-License
General	I-License
Public	I-License
License	I-License
.	O
</s>
<s>
The	O
vast	O
majority	O
of	O
free	O
software	O
uses	O
undisputed	O
free-software	B-License
licenses	I-License
;	O
however	O
,	O
there	O
have	O
been	O
many	O
debates	O
over	O
whether	O
or	O
not	O
certain	O
other	O
licenses	O
qualify	O
for	O
the	O
definition	O
.	O
</s>
<s>
Examples	O
of	O
licenses	O
that	O
provoked	O
debate	O
were	O
the	O
1.x	O
series	O
of	O
the	O
Apple	B-License
Public	I-License
Source	I-License
License	I-License
,	O
which	O
were	O
accepted	O
by	O
the	O
Open	O
Source	O
Initiative	O
but	O
not	O
by	O
the	B-Operating_System
Free	I-Operating_System
Software	I-Operating_System
Foundation	I-Operating_System
or	O
Debian	O
and	O
the	O
RealNetworks	B-License
Public	I-License
Source	I-License
License	I-License
,	O
which	O
was	O
accepted	O
by	O
Open	O
Source	O
Initiative	O
and	O
Free	B-Operating_System
Software	I-Operating_System
Foundation	I-Operating_System
but	O
not	O
by	O
Debian	O
.	O
</s>
<s>
Also	O
,	O
the	O
FSF	O
recommended	O
GNU	B-Application
Free	I-Application
Documentation	I-Application
License	I-Application
,	O
which	O
is	O
incompatible	O
with	O
the	O
GPL	B-License
,	O
was	O
considered	O
"	O
non-free	O
"	O
by	O
the	O
Debian	O
project	O
around	O
2006	O
,	O
Nathanael	O
Nerode	O
,	O
and	O
Bruce	O
Perens	O
.	O
</s>
<s>
Debian	O
accepted	O
,	O
in	O
a	O
later	O
resolution	O
,	O
that	O
the	O
GNU	B-Application
FDL	I-Application
complied	O
with	O
the	O
Debian	B-License
Free	I-License
Software	I-License
Guidelines	I-License
when	O
the	O
controversial	O
"	O
invariant	O
section	O
"	O
is	O
removed	O
,	O
but	O
considers	O
it	O
"	O
still	O
not	O
free	O
of	O
trouble	O
"	O
.	O
</s>
<s>
Similarly	O
,	O
the	O
FLOSS	B-Application
Manuals	I-Application
foundation	O
,	O
an	O
organization	O
devoted	O
to	O
creating	O
manuals	O
for	O
free	O
software	O
,	O
decided	O
to	O
eschew	O
the	O
GFDL	B-Application
in	O
favor	O
of	O
the	O
GPL	B-License
for	O
its	O
texts	O
in	O
2007	O
,	O
citing	O
the	O
incompatibility	O
between	O
the	O
two	O
,	O
difficulties	O
in	O
implementing	O
the	O
GFDL	B-Application
,	O
and	O
the	O
fact	O
that	O
the	O
GFDL	B-Application
"	O
does	O
not	O
allow	O
for	O
easy	O
duplication	O
and	O
modification	O
"	O
,	O
especially	O
for	O
digital	O
documentation	O
.	O
</s>
<s>
SLUC	B-License
is	O
a	O
software	B-License
license	I-License
published	O
in	O
Spain	O
in	O
December	O
2006	O
to	O
allow	O
all	O
but	O
military	O
use	O
.	O
</s>
<s>
The	O
writers	O
of	O
the	O
license	O
maintain	O
it	O
is	O
free	O
software	O
,	O
but	O
the	B-Operating_System
Free	I-Operating_System
Software	I-Operating_System
Foundation	I-Operating_System
says	O
it	O
is	O
not	O
free	O
because	O
it	O
infringes	O
the	O
so-called	O
"	O
zero	O
freedom	O
"	O
of	O
the	O
GPL	B-License
,	O
that	O
is	O
,	O
the	O
freedom	O
to	O
use	O
the	O
software	O
for	O
any	O
purpose	O
.	O
</s>
<s>
While	O
historically	O
the	O
most	O
widely	O
used	O
FOSS	B-License
license	O
has	O
been	O
the	O
GPLv2	O
,	O
in	O
2015	O
,	O
according	O
to	O
Black	O
Duck	O
Software	O
the	O
permissive	B-License
MIT	B-License
license	I-License
dethroned	O
the	O
GPLv2	O
to	O
the	O
second	O
place	O
while	O
the	O
permissive	B-License
Apache	B-Application
License	I-Application
follows	O
at	O
third	O
place	O
.	O
</s>
<s>
Daniel	O
German	O
,	O
professor	O
in	O
the	O
Department	O
of	O
Computer	O
Science	O
at	O
the	O
University	O
of	O
Victoria	O
in	O
Canada	O
,	O
presented	O
a	O
talk	O
in	O
2013	O
about	O
the	O
methodological	O
challenges	O
in	O
determining	O
which	O
are	O
the	O
most	O
widely	O
used	O
free-software	B-License
licenses	I-License
,	O
and	O
showed	O
how	O
he	O
could	O
not	O
replicate	O
the	O
result	O
from	O
Black	O
Duck	O
Software	O
.	O
</s>
<s>
A	O
GitHub	B-Application
study	O
in	O
2015	O
on	O
their	O
statistical	O
data	O
found	O
that	O
the	B-License
MIT	I-License
license	I-License
was	O
the	O
most	O
prominent	O
FOSS	B-License
license	O
on	O
that	O
platform	O
.	O
</s>
<s>
In	O
June	O
2016	O
an	O
analysis	O
of	O
the	O
Fedora	O
Project	O
's	O
packages	O
showed	O
as	O
most	O
used	O
licenses	O
the	O
GPL	B-License
family	O
,	O
followed	O
by	O
MIT	B-License
,	O
BSD	B-Operating_System
,	O
the	O
LGP	O
family	O
,	O
Artistic	O
(	O
for	O
Perl	O
packages	O
)	O
,	O
LPPL	O
(	O
for	O
texlive	B-General_Concept
packages	O
)	O
,	O
and	O
ASL	O
.	O
</s>
