<s>
The	O
.NET	B-Application
Framework	I-Application
(	O
pronounced	O
as	O
"	O
dot	O
net	O
"	O
)	O
is	O
a	O
proprietary	B-Application
software	I-Application
framework	O
developed	O
by	O
Microsoft	O
that	O
runs	O
primarily	O
on	O
Microsoft	B-Application
Windows	I-Application
.	O
</s>
<s>
It	O
was	O
the	O
predominant	O
implementation	O
of	O
the	O
Common	O
Language	O
Infrastructure	O
(	O
CLI	O
)	O
until	O
being	O
superseded	O
by	O
the	O
cross-platform	O
.NET	B-Application
project	O
.	O
</s>
<s>
It	O
includes	O
a	O
large	O
class	B-Application
library	I-Application
called	O
Framework	B-Library
Class	I-Library
Library	I-Library
(	O
FCL	O
)	O
and	O
provides	O
language	B-Language
interoperability	I-Language
(	O
each	O
language	O
can	O
use	O
code	O
written	O
in	O
other	O
languages	O
)	O
across	O
several	O
programming	O
languages	O
.	O
</s>
<s>
Programs	O
written	O
for	O
.NET	B-Application
Framework	I-Application
execute	O
in	O
a	O
software	O
environment	O
(	O
in	O
contrast	O
to	O
a	O
hardware	B-Architecture
environment	O
)	O
named	O
the	O
Common	O
Language	O
Runtime	O
(	O
CLR	O
)	O
.	O
</s>
<s>
The	O
CLR	O
is	O
an	O
application	O
virtual	O
machine	O
that	O
provides	O
services	O
such	O
as	O
security	O
,	O
memory	B-General_Concept
management	I-General_Concept
,	O
and	O
exception	B-General_Concept
handling	I-General_Concept
.	O
</s>
<s>
As	O
such	O
,	O
computer	O
code	O
written	O
using	O
.NET	B-Application
Framework	I-Application
is	O
called	O
"	O
managed	O
code	O
"	O
.	O
</s>
<s>
FCL	O
and	O
CLR	O
together	O
constitute	O
the	O
.NET	B-Application
Framework	I-Application
.	O
</s>
<s>
FCL	O
provides	O
the	O
user	B-Application
interface	I-Application
,	O
data	B-General_Concept
access	I-General_Concept
,	O
database	B-General_Concept
connectivity	I-General_Concept
,	O
cryptography	O
,	O
web	B-Application
application	I-Application
development	I-Application
,	O
numeric	O
algorithms	O
,	O
and	O
network	B-Architecture
communications	I-Architecture
.	O
</s>
<s>
Programmers	O
produce	O
software	O
by	O
combining	O
their	O
source	O
code	O
with	O
.NET	B-Application
Framework	I-Application
and	O
other	O
libraries	O
.	O
</s>
<s>
Microsoft	O
also	O
produces	O
an	O
integrated	B-Application
development	I-Application
environment	I-Application
for	O
.NET	B-Application
software	O
called	O
Visual	B-Application
Studio	I-Application
.	O
</s>
<s>
.NET	B-Application
Framework	I-Application
began	O
as	O
proprietary	B-Application
software	I-Application
,	O
although	O
the	O
firm	O
worked	O
to	O
standardize	O
the	O
software	O
stack	O
almost	O
immediately	O
,	O
even	O
before	O
its	O
first	O
release	O
.	O
</s>
<s>
Despite	O
the	O
standardization	O
efforts	O
,	O
developers	O
,	O
mainly	O
those	O
in	O
the	O
free	B-License
and	I-License
open-source	I-License
software	I-License
communities	O
,	O
expressed	O
their	O
unease	O
with	O
the	O
selected	O
terms	O
and	O
the	O
prospects	O
of	O
any	O
free	B-License
and	I-License
open-source	I-License
implementation	O
,	O
especially	O
regarding	O
software	O
patents	O
.	O
</s>
<s>
Since	O
then	O
,	O
Microsoft	O
has	O
changed	O
.NET	B-Application
development	O
to	O
more	O
closely	O
follow	O
a	O
contemporary	O
model	O
of	O
a	O
community-developed	O
software	O
project	O
,	O
including	O
issuing	O
an	O
update	O
to	O
its	O
patent	O
promising	O
to	O
address	O
the	O
concerns	O
.	O
</s>
<s>
In	O
April	O
2019	O
,	O
Microsoft	O
released	O
.NET	B-Application
Framework	I-Application
4.8	O
,	O
the	O
last	O
version	O
of	O
the	O
framework	O
as	O
a	O
proprietary	B-Application
offering	O
.	O
</s>
<s>
Microsoft	O
began	O
developing	O
.NET	B-Application
Framework	I-Application
in	O
the	O
late	O
1990s	O
,	O
originally	O
under	O
the	O
name	O
of	O
Next	B-Application
Generation	I-Application
Windows	I-Application
Services	I-Application
(	O
NGWS	B-Application
)	O
,	O
as	O
part	O
of	O
the	O
.NET	B-Application
strategy	O
.	O
</s>
<s>
By	O
early	O
2000	O
,	O
the	O
first	O
beta	O
versions	O
of	O
.NET	B-Application
1.0	O
were	O
released	O
.	O
</s>
<s>
In	O
August	O
2000	O
,	O
Microsoft	O
,	O
and	O
Intel	O
worked	O
to	O
standardize	O
Common	O
Language	O
Infrastructure	O
(	O
CLI	O
)	O
and	O
C#	B-Application
.	O
</s>
<s>
While	O
Microsoft	O
and	O
their	O
partners	O
hold	O
patents	O
for	O
CLI	O
and	O
C#	B-Application
,	O
ECMA	O
and	O
ISO	O
require	O
that	O
all	O
patents	O
essential	O
to	O
implementation	O
be	O
made	O
available	O
under	O
"	O
reasonable	O
and	O
non-discriminatory	O
terms	O
"	O
.	O
</s>
<s>
However	O
,	O
this	O
did	O
not	O
apply	O
to	O
the	O
part	O
of	O
the	O
.NET	B-Application
Framework	I-Application
not	O
covered	O
by	O
ECMA-ISO	O
standards	O
,	O
which	O
included	O
Windows	B-Application
Forms	I-Application
,	O
ADO.NET	B-Device
,	O
and	O
ASP.NET	B-Application
.	O
</s>
<s>
On	O
October	O
3	O
,	O
2007	O
,	O
Microsoft	O
announced	O
that	O
the	O
source	O
code	O
for	O
.NET	B-Application
Framework	I-Application
3.5	O
libraries	O
was	O
to	O
become	O
available	O
under	O
the	O
Microsoft	B-License
Reference	I-License
Source	I-License
License	I-License
(	O
Ms-RSL	O
)	O
.	O
</s>
<s>
The	O
source	O
code	O
repository	O
became	O
available	O
online	O
on	O
January	O
16	O
,	O
2008	O
,	O
and	O
included	O
BCL	O
,	O
ASP.NET	B-Application
,	O
ADO.NET	B-Device
,	O
Windows	B-Application
Forms	I-Application
,	O
WPF	O
,	O
and	O
XML	O
.	O
</s>
<s>
Scott	O
Guthrie	O
of	O
Microsoft	O
promised	O
that	O
LINQ	B-Language
,	O
WCF	O
,	O
and	O
WF	O
libraries	O
were	O
being	O
added	O
.	O
</s>
<s>
The	O
.NET	B-Operating_System
Compact	I-Operating_System
Framework	I-Operating_System
and	O
.NET	B-Application
Micro	I-Application
Framework	I-Application
variants	O
of	O
the	O
.NET	B-Application
Framework	I-Application
provided	O
support	O
for	O
other	O
Microsoft	O
platforms	O
such	O
as	O
Windows	B-Operating_System
Mobile	I-Operating_System
,	O
Windows	B-Operating_System
CE	I-Operating_System
and	O
other	O
resource-constrained	O
embedded	O
devices	O
.	O
</s>
<s>
Silverlight	B-Application
provided	O
support	O
for	O
web	B-Application
browsers	I-Application
via	O
plug-ins	O
.	O
</s>
<s>
Prior	O
projects	O
like	O
Mono	B-Application
existed	O
in	O
a	O
legal	O
grey	O
area	O
because	O
Microsoft	O
's	O
earlier	O
grants	O
applied	O
only	O
to	O
the	O
technology	O
in	O
"	O
covered	O
specifications	O
"	O
,	O
including	O
strictly	O
the	O
4th	O
editions	O
each	O
of	O
ECMA-334	B-Application
and	O
ECMA-335	O
.	O
</s>
<s>
The	O
new	O
patent	O
promise	O
,	O
however	O
,	O
places	O
no	O
ceiling	O
on	O
the	O
specification	O
version	O
,	O
and	O
even	O
extends	O
to	O
any	O
.NET	B-Application
runtime	O
technologies	O
documented	O
on	O
MSDN	O
that	O
have	O
not	O
been	O
formally	O
specified	O
by	O
the	O
ECMA	O
group	O
,	O
if	O
a	O
project	O
chooses	O
to	O
implement	O
them	O
.	O
</s>
<s>
This	O
allows	O
Mono	B-Application
and	O
other	O
projects	O
to	O
maintain	O
feature	O
parity	O
with	O
modern	O
.NET	B-Application
features	O
that	O
have	O
been	O
introduced	O
since	O
the	O
4th	O
edition	O
was	O
published	O
without	O
being	O
at	O
risk	O
of	O
patent	O
litigation	O
over	O
the	O
implementation	O
of	O
those	O
features	O
.	O
</s>
<s>
On	O
March	O
31	O
,	O
2016	O
,	O
Microsoft	O
announced	O
at	O
Microsoft	O
Build	O
that	O
they	O
will	O
completely	O
relicense	O
Mono	B-Application
under	O
an	O
MIT	B-License
License	I-License
even	O
in	O
scenarios	O
where	O
formerly	O
a	O
commercial	O
license	O
was	O
needed	O
.	O
</s>
<s>
Microsoft	O
also	O
supplemented	O
its	O
prior	O
patent	O
promise	O
for	O
Mono	B-Application
,	O
stating	O
that	O
they	O
will	O
not	O
assert	O
any	O
"	O
applicable	O
patents	O
"	O
against	O
parties	O
that	O
are	O
"	O
using	O
,	O
selling	O
,	O
offering	O
for	O
sale	O
,	O
importing	O
,	O
or	O
distributing	O
Mono.	O
"	O
</s>
<s>
It	O
was	O
announced	O
that	O
the	O
Mono	B-Application
Project	I-Application
was	O
contributed	O
to	O
the	O
.NET	B-Application
Foundation	O
.	O
</s>
<s>
These	O
developments	O
followed	O
the	O
acquisition	O
of	O
Xamarin	B-Application
,	O
which	O
began	O
in	O
February	O
2016	O
and	O
was	O
finished	O
on	O
March	O
18	O
,	O
2016	O
.	O
</s>
<s>
Microsoft	O
's	O
press	O
release	O
highlights	O
that	O
the	O
cross-platform	O
commitment	O
now	O
allows	O
for	O
a	O
fully	O
open-source	O
,	O
modern	O
server-side	O
.NET	B-Application
stack	O
.	O
</s>
<s>
Microsoft	O
released	O
the	O
source	O
code	O
for	O
WPF	O
,	O
Windows	B-Application
Forms	I-Application
and	O
WinUI	O
on	O
December	O
4	O
,	O
2018	O
.	O
</s>
<s>
By	O
implementing	O
the	O
core	O
aspects	O
of	O
.NET	B-Application
Framework	I-Application
within	O
the	O
scope	O
of	O
CLI	O
,	O
these	O
functions	O
will	O
not	O
be	O
tied	O
to	O
one	O
language	O
but	O
will	O
be	O
available	O
across	O
the	O
many	O
languages	O
supported	O
by	O
the	O
framework	O
.	O
</s>
<s>
.NET	B-Application
Framework	I-Application
includes	O
the	O
Common	O
Language	O
Runtime	O
(	O
CLR	O
)	O
.	O
</s>
<s>
It	O
serves	O
as	O
the	O
execution	O
engine	O
of	O
.NET	B-Application
Framework	I-Application
and	O
offers	O
many	O
services	O
such	O
as	O
memory	B-General_Concept
management	I-General_Concept
,	O
type	B-Language
safety	I-Language
,	O
exception	B-General_Concept
handling	I-General_Concept
,	O
garbage	B-General_Concept
collection	I-General_Concept
,	O
security	O
and	O
thread	B-Operating_System
management	I-Operating_System
.	O
</s>
<s>
All	O
programs	O
written	O
for	O
.NET	B-Application
Framework	I-Application
are	O
executed	O
by	O
the	O
CLR	O
.	O
</s>
<s>
Programs	O
written	O
for	O
.NET	B-Application
Framework	I-Application
are	O
compiled	O
into	O
Common	O
Intermediate	O
Language	O
code	O
(	O
CIL	O
)	O
,	O
as	O
opposed	O
to	O
being	O
directly	O
compiled	O
into	O
machine	B-Language
code	I-Language
.	O
</s>
<s>
During	O
execution	O
,	O
an	O
architecture-specific	O
just-in-time	O
compiler	O
(	O
JIT	O
)	O
turns	O
the	O
CIL	O
code	O
into	O
machine	B-Language
code	I-Language
.	O
</s>
<s>
The	O
complete	O
name	O
of	O
an	O
assembly	O
(	O
not	O
to	O
be	O
confused	O
with	O
the	O
file	O
name	O
on	O
disk	O
)	O
contains	O
its	O
simple	O
text	O
name	O
,	O
version	O
number	O
,	O
culture	O
,	O
and	O
public	B-Application
key	I-Application
token	O
.	O
</s>
<s>
A	O
private	B-Application
key	I-Application
can	O
also	O
be	O
used	O
by	O
the	O
creator	O
of	O
the	O
assembly	O
for	O
strong	O
naming	O
.	O
</s>
<s>
The	O
public	B-Application
key	I-Application
token	O
identifies	O
which	O
private	B-Application
key	I-Application
an	O
assembly	O
is	O
signed	O
with	O
.	O
</s>
<s>
Only	O
the	O
creator	O
of	O
the	O
key	B-Application
pair	I-Application
(	O
typically	O
the	O
person	O
signing	O
the	O
assembly	O
)	O
can	O
sign	O
assemblies	O
that	O
have	O
the	O
same	O
strong	O
name	O
as	O
a	O
prior	O
version	O
assembly	O
,	O
since	O
the	O
creator	O
possesses	O
the	O
private	B-Application
key	I-Application
.	O
</s>
<s>
Starting	O
with	O
Visual	B-Application
Studio	I-Application
2015	O
,	O
.NET	B-Application
Native	O
compilation	O
technology	O
allows	O
for	O
the	O
compilation	O
of	O
.NET	B-Application
code	O
of	O
Universal	O
Windows	O
Platform	O
apps	O
directly	O
to	O
machine	B-Language
code	I-Language
rather	O
than	O
CIL	O
code	O
,	O
but	O
the	O
app	O
must	O
be	O
written	O
in	O
either	O
C#	B-Application
or	O
Visual	B-Language
Basic.NET	I-Language
.	O
</s>
<s>
.NET	B-Application
Framework	I-Application
includes	O
an	O
implementation	O
of	O
the	O
CLI	O
foundational	O
Standard	O
Libraries	O
.	O
</s>
<s>
The	O
.NET	B-Application
Framework	I-Application
Class	B-Application
Library	I-Application
(	O
FCL	O
)	O
is	O
organized	O
in	O
a	O
hierarchy	O
of	O
namespaces	O
.	O
</s>
<s>
Most	O
of	O
the	O
built-in	O
application	B-Application
programming	I-Application
interfaces	I-Application
(	O
APIs	B-General_Concept
)	O
are	O
part	O
of	O
either	O
System	O
.	O
</s>
<s>
These	O
class	B-Application
libraries	I-Application
implement	O
many	O
common	O
functions	O
,	O
such	O
as	O
file	O
reading	O
and	O
writing	O
,	O
graphic	O
rendering	O
,	O
database	O
interaction	O
,	O
and	O
XML	O
document	O
manipulation	O
.	O
</s>
<s>
The	O
class	B-Application
libraries	I-Application
are	O
available	O
for	O
all	O
CLI	B-Language
compliant	I-Language
languages	I-Language
.	O
</s>
<s>
The	O
FCL	O
implements	O
the	O
CLI	O
Base	O
Class	B-Application
Library	I-Application
(	O
BCL	O
)	O
and	O
other	O
class	B-Application
libraries	I-Application
—	O
some	O
are	O
specified	O
by	O
CLI	O
and	O
other	O
are	O
Microsoft	O
specific	O
.	O
</s>
<s>
BCL	O
includes	O
a	O
small	O
subset	O
of	O
the	O
entire	O
class	B-Application
library	I-Application
and	O
is	O
the	O
core	O
set	O
of	O
classes	O
that	O
serve	O
as	O
the	O
basic	O
API	B-General_Concept
of	O
CLR	O
.	O
</s>
<s>
For	O
.NET	B-Application
Framework	I-Application
most	O
classes	O
considered	O
being	O
part	O
of	O
BCL	O
reside	O
in	O
mscorlib.dll	B-Application
,	O
System.dll	O
and	O
System.Core.dll	O
.	O
</s>
<s>
BCL	O
classes	O
are	O
available	O
in	O
.NET	B-Application
Framework	I-Application
as	O
well	O
as	O
its	O
alternative	O
implementations	O
including	O
.NET	B-Operating_System
Compact	I-Operating_System
Framework	I-Operating_System
,	O
Microsoft	B-Application
Silverlight	I-Application
,	O
.NET	B-Application
Core	I-Application
and	O
Mono	B-Application
.	O
</s>
<s>
FCL	O
refers	O
to	O
the	O
entire	O
class	B-Application
library	I-Application
that	O
ships	O
with	O
.NET	B-Application
Framework	I-Application
.	O
</s>
<s>
It	O
includes	O
an	O
expanded	O
set	O
of	O
libraries	O
,	O
including	O
BCL	O
,	O
Windows	B-Application
Forms	I-Application
,	O
ASP.NET	B-Application
,	O
and	O
Windows	B-Device
Presentation	I-Device
Foundation	I-Device
(	O
WPF	O
)	O
but	O
also	O
extensions	O
to	O
the	O
base	O
class	B-Application
libraries	I-Application
ADO.NET	B-Device
,	O
Language	B-Language
Integrated	I-Language
Query	I-Language
(	O
LINQ	B-Language
)	O
,	O
Windows	B-Application
Communication	I-Application
Foundation	I-Application
(	O
WCF	O
)	O
,	O
and	O
Workflow	O
Foundation	O
(	O
WF	O
)	O
.	O
</s>
<s>
FCL	O
is	O
much	O
larger	O
in	O
scope	O
than	O
standard	O
libraries	O
for	O
languages	O
like	O
C++	B-Language
,	O
and	O
comparable	O
in	O
scope	O
to	O
standard	B-Library
libraries	I-Library
of	I-Library
Java	I-Library
.	O
</s>
<s>
With	O
the	O
introduction	O
of	O
alternative	O
implementations	O
(	O
e.g.	O
,	O
Silverlight	B-Application
)	O
,	O
Microsoft	O
introduced	O
the	O
concept	O
of	O
Portable	B-Library
Class	I-Library
Libraries	I-Library
(	O
PCL	O
)	O
allowing	O
a	O
consuming	O
library	O
to	O
run	O
on	O
more	O
than	O
one	O
platform	O
.	O
</s>
<s>
With	O
the	O
further	O
proliferation	O
of	O
.NET	B-Application
platforms	I-Application
,	O
the	O
PCL	O
approach	O
failed	O
to	O
scale	O
(	O
PCLs	O
are	O
defined	O
intersections	O
of	O
API	B-General_Concept
surface	O
between	O
two	O
or	O
more	O
platforms	O
)	O
.	O
</s>
<s>
As	O
the	O
next	O
evolutionary	O
step	O
of	O
PCL	O
,	O
the	O
.NET	B-Application
Standard	O
Library	O
was	O
created	O
retroactively	O
based	O
on	O
the	O
System.Runtime.dll	O
based	O
APIs	B-General_Concept
found	O
in	O
UWP	O
and	O
Silverlight	B-Application
.	O
</s>
<s>
New	O
.NET	B-Application
platforms	I-Application
are	O
encouraged	O
to	O
implement	O
a	O
version	O
of	O
the	O
standard	O
library	O
allowing	O
them	O
to	O
re-use	O
extant	O
third-party	O
libraries	O
to	O
run	O
without	O
new	O
versions	O
of	O
them	O
.	O
</s>
<s>
The	O
.NET	B-Application
Standard	O
Library	O
allows	O
an	O
independent	O
evolution	O
of	O
the	O
library	O
and	O
app	O
model	O
layers	O
within	O
the	O
.NET	B-Application
architecture	O
.	O
</s>
<s>
NuGet	B-Application
is	O
the	O
package	O
manager	O
for	O
all	O
.NET	B-Application
platforms	I-Application
.	O
</s>
<s>
It	O
is	O
used	O
to	O
retrieve	O
third-party	O
libraries	O
into	O
a	O
.NET	B-Application
project	O
with	O
a	O
global	O
library	O
feed	O
at	O
NuGet.org	O
.	O
</s>
<s>
Microsoft	O
introduced	O
C++	B-Language
/CLI	I-Language
in	O
Visual	B-Application
Studio	I-Application
2005	O
,	O
which	O
is	O
a	O
language	O
and	O
means	O
of	O
compiling	O
Visual	B-Application
C++	I-Application
programs	O
to	O
run	O
within	O
the	O
.NET	B-Application
Framework	I-Application
.	O
</s>
<s>
Some	O
parts	O
of	O
the	O
C++	B-Language
program	I-Language
still	O
run	O
within	O
an	O
unmanaged	O
Visual	B-Application
C++	I-Application
Runtime	O
,	O
while	O
specially	O
modified	O
parts	O
are	O
translated	O
into	O
CIL	O
code	O
and	O
run	O
with	O
the	O
.NET	B-Application
Framework	I-Application
's	O
CLR	O
.	O
</s>
<s>
Assemblies	O
compiled	O
using	O
the	O
C++	B-Language
/CLI	I-Language
compiler	O
are	O
termed	O
mixed-mode	O
assemblies	O
since	O
they	O
contain	O
native	O
and	O
managed	O
code	O
in	O
the	O
same	O
DLL	O
.	O
</s>
<s>
Such	O
assemblies	O
are	O
more	O
complex	O
to	O
reverse	O
engineer	O
since	O
.NET	B-Application
decompilers	B-Application
such	O
as	O
.NET	B-Application
Reflector	I-Application
reveal	O
only	O
the	O
managed	O
code	O
.	O
</s>
<s>
Because	O
computer	O
systems	O
commonly	O
require	O
interaction	O
between	O
newer	O
and	O
older	O
applications	O
,	O
.NET	B-Application
Framework	I-Application
provides	O
means	O
to	O
access	O
functions	O
implemented	O
in	O
newer	O
and	O
older	O
programs	O
that	O
execute	O
outside	O
.NET	B-Application
environment	O
.	O
</s>
<s>
Access	O
to	O
Component	B-Application
Object	I-Application
Model	I-Application
(	O
COM	O
)	O
components	O
is	O
provided	O
in	O
System	O
.	O
</s>
<s>
Access	O
to	O
.NET	B-Application
functions	O
from	O
native	B-Language
applications	I-Language
is	O
via	O
the	O
reverse	O
P/Invoke	O
function	O
.	O
</s>
<s>
.NET	B-Application
Framework	I-Application
introduces	O
a	O
Common	O
Type	O
System	O
(	O
CTS	O
)	O
that	O
defines	O
all	O
possible	O
data	O
types	O
and	O
programming	O
constructs	O
supported	O
by	O
CLR	O
and	O
how	O
they	O
may	O
or	O
may	O
not	O
interact	O
conforming	O
to	O
CLI	O
specifications	O
.	O
</s>
<s>
Because	O
of	O
this	O
feature	O
,	O
.NET	B-Application
Framework	I-Application
supports	O
the	O
exchange	O
of	O
types	O
and	O
object	O
instances	O
between	O
libraries	O
and	O
applications	O
written	O
using	O
any	B-Language
conforming	I-Language
.NET	I-Language
language	I-Language
.	O
</s>
<s>
CTS	O
and	O
the	O
CLR	O
used	O
in	O
.NET	B-Application
Framework	I-Application
also	O
enforce	O
type	B-Language
safety	I-Language
.	O
</s>
<s>
This	O
also	O
makes	O
most	O
CLI	B-Language
languages	I-Language
statically	O
typed	O
(	O
with	O
or	O
without	O
type	O
inference	O
)	O
.	O
</s>
<s>
However	O
,	O
starting	O
with	O
.NET	B-Application
Framework	I-Application
4.0	O
,	O
the	O
Dynamic	B-Application
Language	I-Application
Runtime	I-Application
extended	O
the	O
CLR	O
,	O
allowing	O
dynamically	O
typed	O
languages	O
to	O
be	O
implemented	O
atop	O
the	O
CLI	O
.	O
</s>
<s>
While	O
Microsoft	O
has	O
never	O
implemented	O
the	O
full	O
framework	O
on	O
any	O
system	O
except	O
Microsoft	B-Application
Windows	I-Application
,	O
it	O
has	O
engineered	O
the	O
framework	O
to	O
be	O
cross-platform	O
,	O
and	O
implementations	O
are	O
available	O
for	O
other	O
operating	O
systems	O
(	O
see	O
Silverlight	B-Application
and	O
§	O
Alternative	O
implementations	O
)	O
.	O
</s>
<s>
Microsoft	O
submitted	O
the	O
specifications	O
for	O
CLI	O
(	O
which	O
includes	O
the	O
core	O
class	B-Application
libraries	I-Application
,	O
CTS	O
,	O
and	O
CIL	O
)	O
,	O
C#	B-Application
,	O
and	O
C++	B-Language
/CLI	I-Language
to	O
both	O
Ecma	O
International	O
(	O
ECMA	O
)	O
and	O
International	O
Organization	O
for	O
Standardization	O
(	O
ISO	O
)	O
,	O
making	O
them	O
available	O
as	O
official	O
standards	O
.	O
</s>
<s>
.NET	B-Application
Framework	I-Application
has	O
its	O
own	O
security	O
mechanism	O
with	O
two	O
general	O
features	O
:	O
Code	O
Access	O
Security	O
(	O
CAS	O
)	O
,	O
and	O
validation	O
and	O
verification	O
.	O
</s>
<s>
Managed	O
CIL	O
bytecode	O
is	O
easier	O
to	O
reverse-engineer	O
than	O
native	B-Language
code	I-Language
,	O
unless	O
obfuscated	O
.	O
</s>
<s>
decompiler	B-Application
programs	O
enable	O
developers	O
with	O
no	O
reverse-engineering	O
skills	O
to	O
view	O
the	O
source	O
code	O
behind	O
unobfuscated	O
.NET	B-Application
assemblies	O
.	O
</s>
<s>
In	O
contrast	O
,	O
apps	O
compiled	O
to	O
native	O
machine	B-Language
code	I-Language
are	O
much	O
harder	O
to	O
reverse-engineer	O
,	O
and	O
source	O
code	O
is	O
almost	O
never	O
produced	O
successfully	O
,	O
mainly	O
because	O
of	O
compiler	O
optimizations	O
and	O
lack	O
of	O
reflection	B-Language
.	O
</s>
<s>
To	O
mitigate	O
this	O
,	O
Microsoft	O
has	O
included	O
Dotfuscator	O
Community	O
Edition	O
with	O
Visual	B-Application
Studio	I-Application
.NET	B-Application
since	O
2002	O
.	O
</s>
<s>
Labs	O
,	O
Turbo	B-Application
,	O
and	O
Red	O
Gate	O
Software	O
.	O
</s>
<s>
Method-level	O
encryption	O
tools	O
for	O
.NET	B-Application
code	O
are	O
available	O
from	O
vendors	O
such	O
as	O
SafeNet	O
.	O
</s>
<s>
CLR	O
frees	O
the	O
developer	O
from	O
the	O
burden	O
of	O
managing	O
memory	O
(	O
allocating	O
and	O
freeing	O
up	O
when	O
done	O
)	O
;	O
it	O
handles	O
memory	B-General_Concept
management	I-General_Concept
itself	O
by	O
detecting	O
when	O
memory	O
can	O
be	O
safely	O
freed	O
.	O
</s>
<s>
Instantiations	O
of	O
.NET	B-Application
types	O
(	O
objects	O
)	O
are	O
allocated	O
from	O
the	O
managed	O
heap	O
;	O
a	O
pool	O
of	O
memory	O
managed	O
by	O
CLR	O
.	O
</s>
<s>
As	O
long	O
as	O
a	O
reference	O
to	O
an	O
object	O
exists	O
,	O
which	O
may	O
be	O
either	O
direct	O
,	O
or	O
via	O
a	O
graph	B-Application
of	O
objects	O
,	O
the	O
object	O
is	O
considered	O
to	O
be	O
in	O
use	O
.	O
</s>
<s>
.NET	B-Application
Framework	I-Application
includes	O
a	O
garbage	B-General_Concept
collector	I-General_Concept
(	O
GC	O
)	O
which	O
runs	O
periodically	O
,	O
on	O
a	O
separate	O
thread	B-Operating_System
from	O
the	O
application	O
's	O
thread	B-Operating_System
,	O
that	O
enumerates	O
all	O
the	O
unusable	O
objects	O
and	O
reclaims	O
the	O
memory	O
allocated	O
to	O
them	O
.	O
</s>
<s>
It	O
is	O
a	O
non-deterministic	O
,	O
compacting	O
,	O
mark-and-sweep	O
garbage	B-General_Concept
collector	I-General_Concept
.	O
</s>
<s>
Each	O
.NET	B-Application
application	O
has	O
a	O
set	O
of	O
roots	O
,	O
which	O
are	O
pointers	O
to	O
objects	O
on	O
the	O
managed	O
heap	O
(	O
managed	O
objects	O
)	O
.	O
</s>
<s>
It	O
uses	O
CLI	O
metadata	O
and	O
reflection	B-Language
to	O
discover	O
the	O
objects	O
encapsulated	O
by	O
an	O
object	O
,	O
and	O
then	O
recursively	O
walk	O
them	O
.	O
</s>
<s>
It	O
then	O
enumerates	O
all	O
the	O
objects	O
on	O
the	O
heap	O
(	O
which	O
were	O
initially	O
allocated	O
contiguously	O
)	O
using	O
reflection	B-Language
.	O
</s>
<s>
The	O
application	O
is	O
resumed	O
after	O
garbage	B-General_Concept
collection	I-General_Concept
ends	O
.	O
</s>
<s>
The	O
latest	O
version	O
of	O
.NET	B-Application
framework	I-Application
uses	O
concurrent	O
garbage	B-General_Concept
collection	I-General_Concept
along	O
with	O
user	O
code	O
,	O
making	O
pauses	O
unnoticeable	O
,	O
because	O
it	O
is	O
done	O
in	O
the	O
background	O
.	O
</s>
<s>
The	O
garbage	B-General_Concept
collector	I-General_Concept
used	O
by	O
.NET	B-Application
Framework	I-Application
is	O
also	O
generational	O
.	O
</s>
<s>
Objects	O
that	O
survive	O
one	O
garbage	B-General_Concept
collection	I-General_Concept
are	O
tagged	O
Generation	O
1	O
.	O
</s>
<s>
Higher	O
generation	O
objects	O
are	O
garbage	B-General_Concept
collected	I-General_Concept
less	O
often	O
than	O
lower	O
generation	O
objects	O
.	O
</s>
<s>
This	O
raises	O
the	O
efficiency	O
of	O
garbage	B-General_Concept
collection	I-General_Concept
,	O
as	O
older	O
objects	O
tend	O
to	O
have	O
longer	O
lifetimes	O
than	O
newer	O
objects	O
.	O
</s>
<s>
When	O
an	O
application	O
is	O
first	O
launched	O
,	O
the	O
.NET	B-Application
Framework	I-Application
compiles	O
the	O
CIL	O
code	O
into	O
executable	O
code	O
using	O
its	O
just-in-time	O
compiler	O
,	O
and	O
caches	O
the	O
executable	O
program	O
into	O
the	O
.NET	B-Application
Native	O
Image	O
Cache	O
.	O
</s>
<s>
To	O
speed	O
up	O
the	O
first	O
launch	O
,	O
developers	O
may	O
use	O
the	O
Native	O
Image	O
Generator	O
utility	O
to	O
manually	O
ahead-of-time	B-Application
compile	I-Application
and	O
cache	O
any	O
.NET	B-Application
application	O
.	O
</s>
<s>
The	O
garbage	B-General_Concept
collector	I-General_Concept
,	O
which	O
is	O
integrated	O
into	O
the	O
environment	O
,	O
can	O
introduce	O
unanticipated	O
delays	O
of	O
execution	O
over	O
which	O
the	O
developer	O
has	O
little	O
direct	O
control	O
.	O
</s>
<s>
"	O
In	O
large	O
applications	O
,	O
the	O
number	O
of	O
objects	O
that	O
the	O
garbage	B-General_Concept
collector	I-General_Concept
needs	O
to	O
work	O
with	O
can	O
become	O
very	O
large	O
,	O
which	O
means	O
it	O
can	O
take	O
a	O
very	O
long	O
time	O
to	O
visit	O
and	O
rearrange	O
all	O
of	O
them.	O
"	O
</s>
<s>
.NET	B-Application
Framework	I-Application
provides	O
support	O
for	O
calling	O
Streaming	B-General_Concept
SIMD	I-General_Concept
Extensions	I-General_Concept
(	O
SSE	O
)	O
via	O
managed	O
code	O
from	O
April	O
2014	O
in	O
Visual	B-Application
Studio	I-Application
2013	O
Update	O
2	O
.	O
</s>
<s>
However	O
,	O
Mono	B-Application
has	O
provided	O
support	O
for	O
SIMD	B-Device
Extensions	O
as	O
of	O
version	O
2.2	O
within	O
the	O
namespace	O
in	O
2009	O
.	O
</s>
<s>
Mono	B-Application
's	O
lead	O
developer	O
Miguel	O
de	O
Icaza	O
has	O
expressed	O
hope	O
that	O
this	O
SIMD	B-Device
support	O
will	O
be	O
adopted	O
by	O
CLR	O
's	O
ECMA	O
standard	O
.	O
</s>
<s>
Streaming	B-General_Concept
SIMD	I-General_Concept
Extensions	I-General_Concept
have	O
been	O
available	O
in	O
x86	B-Operating_System
CPUs	O
since	O
the	O
introduction	O
of	O
the	O
Pentium	B-General_Concept
III	I-General_Concept
.	O
</s>
<s>
Some	O
other	O
architectures	O
such	O
as	O
ARM	B-Architecture
and	O
MIPS	B-Device
also	O
have	O
SIMD	B-Device
extensions	O
.	O
</s>
<s>
.NET	B-Application
Framework	I-Application
was	O
the	O
predominant	O
implementation	O
of	O
.NET	B-Application
technologies	O
,	O
until	O
the	O
release	O
of	O
.NET	B-Application
.	O
</s>
<s>
.NET	B-Application
Micro	I-Application
Framework	I-Application
is	O
a	O
.NET	B-Application
platform	I-Application
for	O
extremely	O
resource-constrained	O
devices	O
.	O
</s>
<s>
It	O
includes	O
a	O
small	O
version	O
of	O
CLR	O
and	O
supports	O
development	O
in	O
C#	B-Application
(	O
though	O
some	O
developers	O
were	O
able	O
to	O
use	O
VB.NET	B-Language
,	O
albeit	O
with	O
an	O
amount	O
of	O
hacking	O
,	O
and	O
with	O
limited	O
functionalities	O
)	O
and	O
debugging	O
(	O
in	O
an	O
emulator	O
or	O
on	O
hardware	B-Architecture
)	O
,	O
both	O
using	O
Microsoft	B-Application
Visual	I-Application
Studio	I-Application
.	O
</s>
<s>
It	O
also	O
features	O
a	O
subset	O
of	O
.NET	B-Application
Framework	I-Application
Class	B-Application
Library	I-Application
(	O
about	O
70	O
classes	O
with	O
about	O
420	O
methods	O
)	O
,	O
a	O
GUI	B-Application
framework	O
loosely	O
based	O
on	O
WPF	O
,	O
and	O
additional	O
libraries	O
specific	O
to	O
embedded	O
applications	O
.	O
</s>
<s>
Mono	B-Application
is	O
an	O
implementation	O
of	O
CLI	O
and	O
FCL	O
,	O
and	O
provides	O
added	O
functions	O
.	O
</s>
<s>
It	O
is	O
licensed	O
as	O
free	B-Application
software	I-Application
under	O
the	B-License
MIT	I-License
License	I-License
.	O
</s>
<s>
It	O
includes	O
support	O
for	O
ASP.NET	B-Application
,	O
ADO.NET	B-Device
,	O
and	O
Windows	B-Application
Forms	I-Application
libraries	O
for	O
a	O
wide	O
range	O
of	O
architectures	O
and	O
operating	O
systems	O
.	O
</s>
<s>
It	O
also	O
includes	O
C#	B-Application
and	O
VB.NET	B-Language
compilers	O
.	O
</s>
<s>
Portable.NET	B-Application
(	O
part	O
of	O
DotGNU	B-Application
)	O
provides	O
an	O
implementation	O
of	O
CLI	O
,	O
parts	O
of	O
FCL	O
,	O
and	O
a	O
C#	B-Application
compiler	O
.	O
</s>
<s>
Microsoft	O
Shared	B-Application
Source	I-Application
Common	I-Application
Language	I-Application
Infrastructure	I-Application
is	O
a	O
non-free	O
implementation	O
of	O
CLR	O
.	O
</s>
<s>
Thus	O
,	O
it	O
does	O
not	O
contain	O
all	O
features	O
of	O
version	O
2.0	O
of	O
.NET	B-Application
Framework	I-Application
.	O
</s>
<s>
It	O
is	O
free	B-Application
software	I-Application
using	O
an	O
open	O
source	O
MIT	B-License
License	I-License
.	O
</s>
