<s>
The	O
X	B-Operating_System
Window	I-Operating_System
System	I-Operating_System
(	O
X11	B-Operating_System
,	O
or	O
simply	O
X	B-Operating_System
)	O
is	O
a	O
windowing	B-Application
system	I-Application
for	O
bitmap	O
displays	O
,	O
common	O
on	O
Unix-like	B-Operating_System
operating	I-Operating_System
systems	I-Operating_System
.	O
</s>
<s>
X	B-Operating_System
provides	O
the	O
basic	O
framework	B-Architecture
for	O
a	O
GUI	O
environment	O
:	O
drawing	O
and	O
moving	O
windows	O
on	O
the	O
display	B-Device
device	O
and	O
interacting	O
with	O
a	O
mouse	O
and	O
keyboard	O
.	O
</s>
<s>
X	B-Operating_System
does	O
not	O
mandate	O
the	O
user	O
interfacethis	O
is	O
handled	O
by	O
individual	O
programs	O
.	O
</s>
<s>
As	O
such	O
,	O
the	O
visual	O
styling	O
of	O
X-based	B-Operating_System
environments	O
varies	O
greatly	O
;	O
different	O
programs	O
may	O
present	O
radically	O
different	O
interfaces	O
.	O
</s>
<s>
X	B-Operating_System
originated	O
as	O
part	O
of	O
Project	B-Operating_System
Athena	I-Operating_System
at	O
Massachusetts	O
Institute	O
of	O
Technology	O
(	O
MIT	O
)	O
in	O
1984	O
.	O
</s>
<s>
The	O
X	B-Operating_System
protocol	O
has	O
been	O
at	O
version	O
11	O
(	O
hence	O
"	O
X11	B-Operating_System
"	O
)	O
since	O
September	O
1987	O
.	O
</s>
<s>
The	O
X.Org	B-Application
Foundation	I-Application
leads	O
the	O
X	B-Operating_System
project	O
,	O
with	O
the	O
current	O
reference	O
implementation	O
,	O
X.Org	B-Operating_System
Server	I-Operating_System
,	O
available	O
as	O
free	B-Application
and	O
open-source	B-Application
software	I-Application
under	O
the	B-License
MIT	I-License
License	I-License
and	O
similar	O
permissive	O
licenses	O
.	O
</s>
<s>
X	B-Operating_System
is	O
an	O
architecture-independent	O
system	O
for	O
remote	O
graphical	O
user	B-Application
interfaces	I-Application
and	O
input	O
device	O
capabilities	O
.	O
</s>
<s>
Each	O
person	O
using	O
a	O
networked	O
terminal	B-General_Concept
has	O
the	O
ability	O
to	O
interact	O
with	O
the	O
display	B-Device
with	O
any	O
type	O
of	O
user	O
input	O
device	O
.	O
</s>
<s>
In	O
its	O
standard	O
distribution	O
it	O
is	O
a	O
complete	O
,	O
albeit	O
simple	O
,	O
display	B-Device
and	O
interface	O
solution	O
which	O
delivers	O
a	O
standard	O
toolkit	B-Library
and	O
protocol	B-Protocol
stack	I-Protocol
for	O
building	O
graphical	O
user	B-Application
interfaces	I-Application
on	O
most	O
Unix-like	B-Operating_System
operating	I-Operating_System
systems	I-Operating_System
and	O
OpenVMS	B-Operating_System
,	O
and	O
has	O
been	O
ported	O
to	O
many	O
other	O
contemporary	O
general	O
purpose	O
operating	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
X	B-Operating_System
provides	O
the	O
basic	O
framework	B-Architecture
,	O
or	O
primitives	O
,	O
for	O
building	O
such	O
GUI	O
environments	O
:	O
drawing	O
and	O
moving	O
windows	O
on	O
the	O
display	B-Device
and	O
interacting	O
with	O
a	O
mouse	O
,	O
keyboard	O
or	O
touchscreen	O
.	O
</s>
<s>
X	B-Operating_System
does	O
not	O
mandate	O
the	O
user	B-Application
interface	I-Application
;	O
individual	O
client	B-Protocol
programs	I-Protocol
handle	O
this	O
.	O
</s>
<s>
Programs	O
may	O
use	O
X	B-Operating_System
's	O
graphical	O
abilities	O
with	O
no	O
user	B-Application
interface	I-Application
.	O
</s>
<s>
As	O
such	O
,	O
the	O
visual	O
styling	O
of	O
X-based	B-Operating_System
environments	O
varies	O
greatly	O
;	O
different	O
programs	O
may	O
present	O
radically	O
different	O
interfaces	O
.	O
</s>
<s>
Unlike	O
most	O
earlier	O
display	B-Device
protocols	O
,	O
X	B-Operating_System
was	O
specifically	O
designed	O
to	O
be	O
used	O
over	O
network	O
connections	O
rather	O
than	O
on	O
an	O
integral	O
or	O
attached	O
display	B-Device
device	O
.	O
</s>
<s>
X	B-Operating_System
features	O
network	B-General_Concept
transparency	I-General_Concept
,	O
which	O
means	O
an	O
X	B-Operating_System
program	O
running	O
on	O
a	O
computer	O
somewhere	O
on	O
a	O
network	O
(	O
such	O
as	O
the	O
Internet	O
)	O
can	O
display	B-Device
its	O
user	B-Application
interface	I-Application
on	O
an	O
X	B-Operating_System
server	O
running	O
on	O
some	O
other	O
computer	O
on	O
the	O
network	O
.	O
</s>
<s>
The	O
X	B-Operating_System
server	O
is	O
typically	O
the	O
provider	O
of	O
graphics	O
resources	O
and	O
keyboard/mouse	O
events	O
to	O
X	B-Operating_System
clients	B-Protocol
,	O
meaning	O
that	O
the	O
X	B-Operating_System
server	O
is	O
usually	O
running	O
on	O
the	O
computer	O
in	O
front	O
of	O
a	O
human	O
user	O
,	O
while	O
the	O
X	B-Operating_System
client	B-Protocol
applications	I-Protocol
run	O
anywhere	O
on	O
the	O
network	O
and	O
communicate	O
with	O
the	O
user	O
's	O
computer	O
to	O
request	O
the	O
rendering	O
of	O
graphics	O
content	O
and	O
receive	O
events	O
from	O
input	O
devices	O
including	O
keyboards	O
and	O
mice	O
.	O
</s>
<s>
The	O
fact	O
that	O
the	O
term	O
"	O
server	O
"	O
is	O
applied	O
to	O
the	O
software	O
in	O
front	O
of	O
the	O
user	O
is	O
often	O
surprising	O
to	O
users	O
accustomed	O
to	O
their	O
programs	O
being	O
clients	B-Protocol
to	O
services	O
on	O
remote	O
computers	O
.	O
</s>
<s>
Here	O
,	O
rather	O
than	O
a	O
remote	O
database	O
being	O
the	O
resource	O
for	O
a	O
local	O
app	O
,	O
the	O
user	O
's	O
graphic	O
display	B-Device
and	O
input	O
devices	O
become	O
resources	O
made	O
available	O
by	O
the	O
local	O
X	B-Operating_System
server	O
to	O
both	O
local	O
and	O
remotely	O
hosted	O
X	B-Operating_System
client	B-Protocol
programs	I-Protocol
who	O
need	O
to	O
share	O
the	O
user	O
's	O
graphics	O
and	O
input	O
devices	O
to	O
communicate	O
with	O
the	O
user	O
.	O
</s>
<s>
X	B-Operating_System
's	O
network	O
protocol	O
is	O
based	O
on	O
X	B-Operating_System
command	O
primitives	O
.	O
</s>
<s>
This	O
approach	O
allows	O
both	O
2D	O
and	O
(	O
through	O
extensions	O
like	O
GLX	B-Device
)	O
3D	O
operations	O
by	O
an	O
X	B-Operating_System
client	B-Protocol
application	I-Protocol
which	O
might	O
be	O
running	O
on	O
a	O
different	O
computer	O
to	O
still	O
be	O
fully	O
accelerated	O
on	O
the	O
X	B-Operating_System
server	O
's	O
display	B-Device
.	O
</s>
<s>
For	O
example	O
,	O
in	O
classic	O
OpenGL	O
(	O
before	O
version	O
3.0	O
)	O
,	O
display	B-Device
lists	O
containing	O
large	O
numbers	O
of	O
objects	O
could	O
be	O
constructed	O
and	O
stored	O
entirely	O
in	O
the	O
X	B-Operating_System
server	O
by	O
a	O
remote	O
X	B-Operating_System
client	B-Protocol
program	I-Protocol
,	O
and	O
each	O
then	O
rendered	O
by	O
sending	O
a	O
single	O
glCallList(which )	O
across	O
the	O
network	O
.	O
</s>
<s>
X	B-Operating_System
provides	O
no	O
native	O
support	O
for	O
audio	O
;	O
several	O
projects	O
exist	O
to	O
fill	O
this	O
niche	O
,	O
some	O
also	O
providing	O
transparent	B-General_Concept
network	I-General_Concept
support	O
.	O
</s>
<s>
X	B-Operating_System
uses	O
a	O
client	O
–	O
server	O
model	O
:	O
an	O
X	B-Operating_System
server	O
communicates	O
with	O
various	O
client	B-Protocol
programs	I-Protocol
.	O
</s>
<s>
This	O
client	O
–	O
server	O
terminologythe	O
user	O
's	O
terminal	B-General_Concept
being	O
the	O
server	O
and	O
the	O
applications	O
being	O
the	O
clientsoften	O
confuses	O
new	O
X	B-Operating_System
users	O
,	O
because	O
the	O
terms	O
appear	O
reversed	O
.	O
</s>
<s>
But	O
X	B-Operating_System
takes	O
the	O
perspective	O
of	O
the	O
application	O
,	O
rather	O
than	O
that	O
of	O
the	O
end-user	O
:	O
X	B-Operating_System
provides	O
display	B-Device
and	O
I/O	O
services	O
to	O
applications	O
,	O
so	O
it	O
is	O
a	O
server	O
;	O
applications	O
use	O
these	O
services	O
,	O
thus	O
they	O
are	O
clients	B-Protocol
.	O
</s>
<s>
The	O
communication	O
protocol	O
between	O
server	O
and	O
client	O
operates	O
network-transparently	O
:	O
the	O
client	O
and	O
server	O
may	O
run	O
on	O
the	O
same	O
machine	O
or	O
on	O
different	O
ones	O
,	O
possibly	O
with	O
different	O
architectures	O
and	O
operating	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
An	O
X	B-Operating_System
client	O
itself	O
may	O
emulate	O
an	O
X	B-Operating_System
server	O
by	O
providing	O
display	B-Device
services	O
to	O
other	O
clients	B-Protocol
.	O
</s>
<s>
This	O
is	O
known	O
as	O
"	O
X	B-Operating_System
nesting	O
"	O
.	O
</s>
<s>
Open-source	B-Application
clients	B-Protocol
such	O
as	O
Xnest	O
and	O
Xephyr	O
support	O
such	O
X	B-Operating_System
nesting	O
.	O
</s>
<s>
To	O
run	O
an	O
X	B-Operating_System
client	B-Protocol
application	I-Protocol
on	O
a	O
remote	O
machine	O
,	O
the	O
user	O
may	O
do	O
the	O
following	O
:	O
</s>
<s>
The	O
remote	O
X	B-Operating_System
client	B-Protocol
application	I-Protocol
will	O
then	O
make	O
a	O
connection	O
to	O
the	O
user	O
's	O
local	O
X	B-Operating_System
server	O
,	O
providing	O
display	B-Device
and	O
input	O
to	O
the	O
user	O
.	O
</s>
<s>
Alternatively	O
,	O
the	O
local	O
machine	O
may	O
run	O
a	O
small	O
program	O
that	O
connects	O
to	O
the	O
remote	O
machine	O
and	O
starts	O
the	O
client	B-Protocol
application	I-Protocol
.	O
</s>
<s>
Practical	O
examples	O
of	O
remote	O
clients	B-Protocol
include	O
:	O
</s>
<s>
X	B-Operating_System
primarily	O
defines	O
protocol	O
and	O
graphics	O
primitivesit	O
deliberately	O
contains	O
no	O
specification	O
for	O
application	O
user-interface	B-Application
design	O
,	O
such	O
as	O
button	O
,	O
menu	O
,	O
or	O
window	O
title-bar	O
styles	O
.	O
</s>
<s>
Instead	O
,	O
application	O
softwaresuch	O
as	O
window	B-Application
managers	I-Application
,	O
GUI	O
widget	B-Library
toolkits	I-Library
and	O
desktop	O
environments	O
,	O
or	O
application-specific	O
graphical	O
user	O
interfacesdefine	O
and	O
provide	O
such	O
details	O
.	O
</s>
<s>
As	O
a	O
result	O
,	O
there	O
is	O
no	O
typical	O
X	B-Operating_System
interface	O
and	O
several	O
different	O
desktop	O
environments	O
have	O
become	O
popular	O
among	O
users	O
.	O
</s>
<s>
A	O
window	B-Application
manager	I-Application
controls	O
the	O
placement	O
and	O
appearance	O
of	O
application	O
windows	O
.	O
</s>
<s>
This	O
may	O
result	O
in	O
desktop	O
interfaces	O
reminiscent	O
of	O
those	O
of	O
Microsoft	O
Windows	O
or	O
of	O
the	O
Apple	O
Macintosh	B-Device
(	O
examples	O
include	O
GNOME	B-Application
2	O
,	O
KDE	O
,	O
Xfce	B-Language
)	O
or	O
have	O
radically	O
different	O
controls	O
(	O
such	O
as	O
a	O
tiling	O
window	B-Application
manager	I-Application
,	O
like	O
wmii	O
or	O
Ratpoison	O
)	O
.	O
</s>
<s>
Some	O
interfaces	O
such	O
as	O
Sugar	O
or	O
ChromeOS	B-Operating_System
eschew	O
the	O
desktop	O
metaphor	O
altogether	O
,	O
simplifying	O
their	O
interfaces	O
for	O
specialized	O
applications	O
.	O
</s>
<s>
Window	B-Application
managers	I-Application
range	O
in	O
sophistication	O
and	O
complexity	O
from	O
the	O
bare-bones	O
(	O
e.g.	O
,	O
twm	B-Language
,	O
the	O
basic	O
window	B-Application
manager	I-Application
supplied	O
with	O
X	B-Operating_System
,	O
or	O
evilwm	O
,	O
an	O
extremely	O
light	O
window	B-Application
manager	I-Application
)	O
to	O
the	O
more	O
comprehensive	O
desktop	O
environments	O
such	O
as	O
Enlightenment	O
and	O
even	O
to	O
application-specific	O
window	B-Application
managers	I-Application
for	O
vertical	O
markets	O
such	O
as	O
point-of-sale	O
.	O
</s>
<s>
Many	O
users	O
use	O
X	B-Operating_System
with	O
a	O
desktop	O
environment	O
,	O
which	O
,	O
aside	O
from	O
the	O
window	B-Application
manager	I-Application
,	O
includes	O
various	O
applications	O
using	O
a	O
consistent	O
user	B-Application
interface	I-Application
.	O
</s>
<s>
Popular	O
desktop	O
environments	O
include	O
GNOME	B-Application
,	O
KDE	B-Language
Plasma	I-Language
and	O
Xfce	B-Language
.	O
</s>
<s>
The	O
UNIX	B-Application
98	O
standard	O
environment	O
is	O
the	O
Common	B-Application
Desktop	I-Application
Environment	I-Application
(	O
CDE	B-Application
)	O
.	O
</s>
<s>
The	O
freedesktop.org	O
initiative	O
addresses	O
interoperability	O
between	O
desktops	O
and	O
the	O
components	O
needed	O
for	O
a	O
competitive	O
X	B-Operating_System
desktop	O
.	O
</s>
<s>
The	O
X.Org	O
implementation	O
is	O
the	O
canonical	O
implementation	O
of	O
X	B-Operating_System
.	O
Owing	O
to	O
liberal	O
licensing	O
,	O
a	O
number	O
of	O
variations	O
,	O
both	O
free	B-Application
and	O
open	O
source	O
and	O
proprietary	O
,	O
have	O
appeared	O
.	O
</s>
<s>
Commercial	O
Unix	B-Application
vendors	O
have	O
tended	O
to	O
take	O
the	O
reference	O
implementation	O
and	O
adapt	O
it	O
for	O
their	O
hardware	O
,	O
usually	O
customizing	O
it	O
and	O
adding	O
proprietary	O
extensions	O
.	O
</s>
<s>
Until	O
2004	O
,	O
XFree86	B-Device
provided	O
the	O
most	O
common	O
X	B-Operating_System
variant	O
on	O
free	B-Application
Unix-like	B-Operating_System
systems	I-Operating_System
.	O
</s>
<s>
XFree86	B-Device
started	O
as	O
a	O
port	O
of	O
X	B-Operating_System
to	O
386-compatible	O
PCs	B-Device
and	O
,	O
by	O
the	O
end	O
of	O
the	O
1990s	O
,	O
had	O
become	O
the	O
greatest	O
source	O
of	O
technical	O
innovation	O
in	O
X	B-Operating_System
and	O
the	O
de	O
facto	O
standard	O
of	O
X	B-Operating_System
development	O
.	O
</s>
<s>
Since	O
2004	O
,	O
however	O
,	O
the	O
X.Org	B-Operating_System
Server	I-Operating_System
,	O
a	O
fork	B-Application
of	O
XFree86	B-Device
,	O
has	O
become	O
predominant	O
.	O
</s>
<s>
While	O
it	O
is	O
common	O
to	O
associate	O
X	B-Operating_System
with	O
Unix	B-Application
,	O
X	B-Operating_System
servers	I-Operating_System
also	O
exist	O
natively	O
within	O
other	O
graphical	O
environments	O
.	O
</s>
<s>
VMS	O
Software	O
Inc.	O
'	O
s	O
OpenVMS	B-Operating_System
operating	B-General_Concept
system	I-General_Concept
includes	O
a	O
version	O
of	O
X	B-Operating_System
with	O
Common	B-Application
Desktop	I-Application
Environment	I-Application
(	O
CDE	B-Application
)	O
,	O
known	O
as	O
DECwindows	B-Application
,	O
as	O
its	O
standard	O
desktop	O
environment	O
.	O
</s>
<s>
Apple	O
originally	O
ported	O
X	B-Operating_System
to	O
macOS	B-Application
in	O
the	O
form	O
of	O
X11.app	B-Operating_System
,	O
but	O
that	O
has	O
been	O
deprecated	O
in	O
favor	O
of	O
the	O
XQuartz	B-Operating_System
implementation	O
.	O
</s>
<s>
Third-party	O
servers	O
under	O
Apple	O
's	O
older	O
operating	B-General_Concept
systems	I-General_Concept
in	O
the	O
1990s	O
,	O
System	O
7	O
,	O
and	O
Mac	B-Application
OS	I-Application
8	O
and	O
9	O
,	O
included	O
Apple	O
's	O
MacX	O
and	O
White	O
Pine	O
Software	O
's	O
eXodus	O
.	O
</s>
<s>
Microsoft	O
Windows	O
is	O
not	O
shipped	O
with	O
support	O
for	O
X	B-Operating_System
,	O
but	O
many	O
third-party	O
implementations	O
exist	O
,	O
as	O
free	B-Application
and	I-Application
open	I-Application
source	I-Application
software	I-Application
such	O
as	O
Cygwin/X	B-Application
,	O
and	O
proprietary	O
products	O
such	O
as	O
Exceed	O
,	O
MKS	O
X/Server	O
,	O
Reflection	O
X	B-Operating_System
,	O
X-Win32	O
and	O
Xming	B-Application
.	O
</s>
<s>
There	O
are	O
also	O
Java	O
implementations	O
of	O
X	B-Operating_System
servers	I-Operating_System
.	O
</s>
<s>
The	O
Android	B-Application
X	B-Operating_System
Server	O
is	O
an	O
open	O
source	O
Java	O
implementation	O
that	O
runs	O
on	O
Android	B-Application
devices	O
.	O
</s>
<s>
When	O
an	O
operating	B-General_Concept
system	I-General_Concept
with	O
a	O
native	O
windowing	B-Application
system	I-Application
hosts	O
X	B-Operating_System
in	O
addition	O
,	O
the	O
X	B-Operating_System
system	O
can	O
either	O
use	O
its	O
own	O
normal	O
desktop	O
in	O
a	O
separate	O
host	O
window	O
or	O
it	O
can	O
run	O
rootless	O
,	O
meaning	O
the	O
X	B-Operating_System
desktop	O
is	O
hidden	O
and	O
the	O
host	O
windowing	B-Application
environment	I-Application
manages	O
the	O
geometry	O
and	O
appearance	O
of	O
the	O
hosted	O
X	B-Operating_System
windows	I-Operating_System
within	O
the	O
host	O
screen	O
.	O
</s>
<s>
An	O
X	B-Operating_System
terminal	B-General_Concept
is	O
a	O
thin	B-Device
client	I-Device
that	O
only	O
runs	O
an	O
X	B-Operating_System
server	O
.	O
</s>
<s>
This	O
architecture	O
became	O
popular	O
for	O
building	O
inexpensive	O
terminal	B-General_Concept
parks	O
for	O
many	O
users	O
to	O
simultaneously	O
use	O
the	O
same	O
large	O
computer	O
server	O
to	O
execute	O
application	O
programs	O
as	O
clients	B-Protocol
of	O
each	O
user	O
's	O
X	B-Operating_System
terminal	B-General_Concept
.	O
</s>
<s>
X	B-Operating_System
terminals	O
explore	O
the	O
network	O
(	O
the	O
local	O
broadcast	B-Architecture
domain	I-Architecture
)	O
using	O
the	O
X	B-Language
Display	I-Language
Manager	I-Language
Control	O
Protocol	O
to	O
generate	O
a	O
list	O
of	O
available	O
hosts	O
that	O
are	O
allowed	O
as	O
clients	B-Protocol
.	O
</s>
<s>
One	O
of	O
the	O
client	O
hosts	O
should	O
run	O
an	O
X	B-Language
display	I-Language
manager	I-Language
.	O
</s>
<s>
A	O
limitation	O
of	O
X	B-Operating_System
terminals	O
and	O
most	O
thin	B-Device
clients	I-Device
is	O
that	O
they	O
are	O
not	O
capable	O
of	O
any	O
input	O
or	O
output	O
other	O
than	O
the	O
keyboard	O
,	O
mouse	O
,	O
and	O
display	B-Device
.	O
</s>
<s>
All	O
relevant	O
data	O
is	O
assumed	O
to	O
exist	O
solely	O
on	O
the	O
remote	O
server	O
,	O
and	O
the	O
X	B-Operating_System
terminal	B-General_Concept
user	O
has	O
no	O
methods	O
available	O
to	O
save	O
or	O
load	O
data	O
from	O
a	O
local	O
peripheral	O
device	O
.	O
</s>
<s>
Dedicated	O
(	O
hardware	O
)	O
X	B-Operating_System
terminals	O
have	O
fallen	O
out	O
of	O
use	O
;	O
a	O
PC	B-Device
or	O
modern	O
thin	B-Device
client	I-Device
with	O
an	O
X	B-Operating_System
server	O
typically	O
provides	O
the	O
same	O
functionality	O
at	O
the	O
same	O
,	O
or	O
lower	O
,	O
cost	O
.	O
</s>
<s>
The	O
Unix-Haters	O
Handbook	O
(	O
1994	O
)	O
devoted	O
a	O
full	O
chapter	O
to	O
the	O
problems	O
of	O
X	B-Operating_System
.	O
</s>
<s>
Why	O
X	B-Operating_System
Is	O
Not	O
Our	O
Ideal	O
Window	B-Application
System	I-Application
(	O
1990	O
)	O
by	O
Gajewska	O
,	O
Manasse	O
and	O
McCormack	O
detailed	O
problems	O
in	O
the	O
protocol	O
with	O
recommendations	O
for	O
improvement	O
.	O
</s>
<s>
The	O
lack	O
of	O
design	O
guidelines	O
in	O
X	B-Operating_System
has	O
resulted	O
in	O
several	O
vastly	O
different	O
interfaces	O
,	O
and	O
in	O
applications	O
that	O
have	O
not	O
always	O
worked	O
well	O
together	O
.	O
</s>
<s>
The	O
Inter-Client	B-Operating_System
Communication	I-Operating_System
Conventions	I-Operating_System
Manual	I-Operating_System
(	O
ICCCM	B-Operating_System
)	O
,	O
a	O
specification	O
for	O
client	O
interoperability	O
,	O
has	O
a	O
reputation	O
for	O
being	O
difficult	O
to	O
implement	O
correctly	O
.	O
</s>
<s>
Further	O
standards	O
efforts	O
such	O
as	O
Motif	B-Application
and	O
CDE	B-Application
did	O
not	O
alleviate	O
problems	O
.	O
</s>
<s>
This	O
has	O
frustrated	O
users	O
and	O
programmers	B-Application
.	O
</s>
<s>
Graphics	O
programmers	B-Application
now	O
generally	O
address	O
consistency	O
of	O
application	O
look	B-Application
and	I-Application
feel	I-Application
and	O
communication	O
by	O
coding	O
to	O
a	O
specific	O
desktop	O
environment	O
or	O
to	O
a	O
specific	O
widget	B-Library
toolkit	I-Library
,	O
which	O
also	O
avoids	O
having	O
to	O
deal	O
directly	O
with	O
the	O
ICCCM	B-Operating_System
.	O
</s>
<s>
X	B-Operating_System
also	O
lacks	O
native	O
support	O
for	O
user-defined	O
stored	O
procedures	O
on	O
the	O
X	B-Operating_System
server	O
,	O
in	O
the	O
manner	O
of	O
NeWSthere	O
is	O
no	O
Turing-complete	O
scripting	O
facility	O
.	O
</s>
<s>
Systems	O
built	O
upon	O
X	B-Operating_System
may	O
have	O
accessibility	O
issues	O
that	O
make	O
utilization	O
of	O
a	O
computer	O
difficult	O
for	O
disabled	O
users	O
,	O
including	O
right	O
click	O
,	O
double	O
click	O
,	O
middle	O
click	O
,	O
mouse-over	O
,	O
and	O
focus	B-Application
stealing	I-Application
.	O
</s>
<s>
Some	O
X11	B-Operating_System
clients	B-Protocol
deal	O
with	O
accessibility	O
issues	O
better	O
than	O
others	O
,	O
so	O
persons	O
with	O
accessibility	O
problems	O
are	O
not	O
locked	O
out	O
of	O
using	O
X11	B-Operating_System
.	O
</s>
<s>
However	O
,	O
there	O
is	O
no	O
accessibility	O
standard	O
or	O
accessibility	O
guidelines	O
for	O
X11	B-Operating_System
.	O
</s>
<s>
Within	O
the	O
X11	B-Operating_System
standards	O
process	O
there	O
is	O
no	O
working	O
group	O
on	O
accessibility	O
;	O
however	O
,	O
accessibility	O
needs	O
are	O
being	O
addressed	O
by	O
software	O
projects	O
to	O
provide	O
these	O
features	O
on	O
top	O
of	O
X	B-Operating_System
.	O
</s>
<s>
The	O
Orca	B-Language
project	O
adds	O
accessibility	O
support	O
to	O
the	O
X	B-Operating_System
Window	I-Operating_System
System	I-Operating_System
,	O
including	O
implementing	O
an	O
API	O
(	O
AT-SPI	B-Language
)	O
.	O
</s>
<s>
This	O
is	O
coupled	O
with	O
GNOME	B-Application
's	O
ATK	B-Language
to	O
allow	O
for	O
accessibility	O
features	O
to	O
be	O
implemented	O
in	O
X	B-Operating_System
programs	O
using	O
the	O
GNOME/GTK	O
APIs	O
.	O
</s>
<s>
The	O
other	O
major	O
desktops	O
(	O
LXDE	O
,	O
Xfce	B-Language
and	O
Enlightenment	O
)	O
attempt	O
to	O
be	O
compatible	O
with	O
ATK	B-Language
.	O
</s>
<s>
An	O
X	B-Operating_System
client	O
cannot	O
generally	O
be	O
detached	O
from	O
one	O
server	O
and	O
reattached	O
to	O
another	O
unless	O
its	O
code	O
specifically	O
provides	O
for	O
it	O
(	O
Emacs	B-Application
is	O
one	O
of	O
the	O
few	O
common	O
programs	O
with	O
this	O
ability	O
)	O
.	O
</s>
<s>
As	O
such	O
,	O
moving	O
an	O
entire	O
session	O
from	O
one	O
X	B-Operating_System
server	O
to	O
another	O
is	O
generally	O
not	O
possible	O
.	O
</s>
<s>
However	O
,	O
approaches	O
like	O
Virtual	B-Protocol
Network	I-Protocol
Computing	I-Protocol
(	O
VNC	B-Protocol
)	O
,	O
NX	B-Application
and	O
Xpra	B-Application
allow	O
a	O
virtual	O
session	O
to	O
be	O
reached	O
from	O
different	O
X	B-Operating_System
servers	I-Operating_System
(	O
in	O
a	O
manner	O
similar	O
to	O
GNU	B-Application
Screen	I-Application
in	O
relation	O
to	O
terminals	O
)	O
,	O
and	O
other	O
applications	O
and	O
toolkits	O
provide	O
related	O
facilities	O
.	O
</s>
<s>
Workarounds	O
like	O
x11vnc	B-Application
(	O
VNC	B-Protocol
:0	O
viewers	O
)	O
,	O
Xpra	B-Application
's	O
shadow	O
mode	O
and	O
NX	B-Application
's	O
nxagent	O
shadow	O
mode	O
also	O
exist	O
to	O
make	O
the	O
current	O
X-server	B-Operating_System
screen	O
available	O
.	O
</s>
<s>
This	O
ability	O
allows	O
the	O
user	B-Application
interface	I-Application
(	O
mouse	O
,	O
keyboard	O
,	O
monitor	O
)	O
of	O
a	O
running	O
application	O
to	O
be	O
switched	O
from	O
one	O
location	O
to	O
another	O
without	O
stopping	O
and	O
restarting	O
the	O
application	O
.	O
</s>
<s>
Network	O
traffic	O
between	O
an	O
X	B-Operating_System
server	O
and	O
remote	O
X	B-Operating_System
clients	B-Protocol
is	O
not	O
encrypted	O
by	O
default	O
.	O
</s>
<s>
An	O
attacker	O
with	O
a	O
packet	B-Protocol
sniffer	I-Protocol
can	O
intercept	O
it	O
,	O
making	O
it	O
possible	O
to	O
view	O
anything	O
displayed	O
to	O
or	O
sent	O
from	O
the	O
user	O
's	O
screen	O
.	O
</s>
<s>
The	O
most	O
common	O
way	O
to	O
encrypt	O
X	B-Operating_System
traffic	O
is	O
to	O
establish	O
a	O
Secure	B-Protocol
Shell	I-Protocol
(	O
SSH	B-Protocol
)	O
tunnel	O
for	O
communication	O
.	O
</s>
<s>
Like	O
all	O
thin	B-Device
clients	I-Device
,	O
when	O
using	O
X	B-Operating_System
across	O
a	O
network	O
,	O
bandwidth	O
limitations	O
can	O
impede	O
the	O
use	O
of	O
bitmap-intensive	O
applications	O
that	O
require	O
rapidly	O
updating	O
large	O
portions	O
of	O
the	O
screen	O
with	O
low	O
latency	B-Protocol
,	O
such	O
as	O
3D	O
animation	O
or	O
photo	O
editing	O
.	O
</s>
<s>
In	O
contrast	O
,	O
modern	O
versions	O
of	O
X	B-Operating_System
generally	O
have	O
extensions	O
such	O
as	O
MESA	B-Application
allowing	O
local	O
display	B-Device
of	O
a	O
local	O
program	O
's	O
graphics	O
to	O
be	O
optimized	O
to	O
bypass	O
the	O
network	O
model	O
and	O
directly	O
control	O
the	O
video	O
card	O
,	O
for	O
use	O
of	O
full-screen	O
video	O
,	O
rendered	O
3D	O
applications	O
,	O
and	O
other	O
such	O
applications	O
.	O
</s>
<s>
X	B-Operating_System
's	O
design	O
requires	O
the	O
clients	B-Protocol
and	O
server	O
to	O
operate	O
separately	O
,	O
and	O
device	B-Operating_System
independence	I-Operating_System
and	O
the	O
separation	O
of	O
client	O
and	O
server	O
incur	O
overhead	O
.	O
</s>
<s>
Most	O
of	O
the	O
overhead	O
comes	O
from	O
network	O
round-trip	O
delay	O
time	O
between	O
client	O
and	O
server	O
(	O
latency	B-Protocol
)	O
rather	O
than	O
from	O
the	O
protocol	O
itself	O
:	O
the	O
best	O
solutions	O
to	O
performance	O
issues	O
depend	O
on	O
efficient	O
application	O
design	O
.	O
</s>
<s>
A	O
common	O
criticism	O
of	O
X	B-Operating_System
is	O
that	O
its	O
network	O
features	O
result	O
in	O
excessive	O
complexity	O
and	O
decreased	O
performance	O
if	O
only	O
used	O
locally	O
.	O
</s>
<s>
Modern	O
X	B-Operating_System
implementations	O
use	O
Unix	B-Protocol
domain	I-Protocol
sockets	I-Protocol
for	O
efficient	O
connections	O
on	O
the	O
same	O
host	O
.	O
</s>
<s>
Additionally	O
shared	B-Operating_System
memory	I-Operating_System
(	O
via	O
the	O
MIT-SHM	B-Device
extension	O
)	O
can	O
be	O
employed	O
for	O
faster	O
client	O
–	O
server	O
communication	O
.	O
</s>
<s>
However	O
,	O
the	O
programmer	B-Application
must	O
still	O
explicitly	O
activate	O
and	O
use	O
the	O
shared	B-Operating_System
memory	I-Operating_System
extension	O
.	O
</s>
<s>
It	O
is	O
also	O
necessary	O
to	O
provide	O
fallback	O
paths	O
in	O
order	O
to	O
stay	O
compatible	O
with	O
older	O
implementations	O
,	O
and	O
in	O
order	O
to	O
communicate	O
with	O
non-local	O
X	B-Operating_System
servers	I-Operating_System
.	O
</s>
<s>
Some	O
people	O
have	O
attempted	O
writing	O
alternatives	O
to	O
and	O
replacements	O
for	O
X	B-Operating_System
.	O
</s>
<s>
Historical	O
alternatives	O
include	O
Sun	O
's	O
NeWS	O
and	O
NeXT	O
's	O
Display	B-Device
PostScript	B-Language
,	O
both	O
PostScript-based	O
systems	O
supporting	O
user-definable	O
display-side	O
procedures	O
,	O
which	O
X	B-Operating_System
lacked	O
.	O
</s>
<s>
macOS	B-Application
(	O
and	O
its	O
mobile	O
counterpart	O
,	O
iOS	B-Application
)	O
implements	O
its	O
windowing	B-Application
system	I-Application
,	O
which	O
is	O
known	O
as	O
Quartz	B-Operating_System
.	O
</s>
<s>
When	O
Apple	O
Computer	O
bought	O
NeXT	O
,	O
and	O
used	O
NeXTSTEP	B-Application
to	O
construct	O
Mac	B-Application
OS	I-Application
X	I-Application
,	O
it	O
replaced	O
Display	B-Device
PostScript	B-Language
with	O
Quartz	B-Operating_System
.	O
</s>
<s>
Mike	O
Paquette	O
,	O
one	O
of	O
the	O
authors	O
of	O
Quartz	B-Operating_System
,	O
explained	O
that	O
if	O
Apple	O
had	O
added	O
support	O
for	O
all	O
the	O
features	O
it	O
wanted	O
to	O
include	O
into	O
X11	B-Operating_System
,	O
it	O
would	O
not	O
bear	O
much	O
resemblance	O
to	O
X11	B-Operating_System
nor	O
be	O
compatible	O
with	O
other	O
servers	O
anyway	O
.	O
</s>
<s>
Plan	B-Operating_System
9	I-Operating_System
uses	O
rio	B-Language
.	O
</s>
<s>
Haiku	O
has	O
its	O
own	O
windowing	B-Application
system	I-Application
.	O
</s>
<s>
HelenOS	B-Operating_System
has	O
its	O
own	O
windowing	B-Application
system	I-Application
.	O
</s>
<s>
Android	B-Application
,	O
which	O
runs	O
on	O
the	O
Linux	B-Operating_System
kernel	I-Operating_System
,	O
uses	O
its	O
own	O
system	O
for	O
drawing	O
the	O
user	B-Application
interface	I-Application
known	O
as	O
SurfaceFlinger	B-Application
.	O
</s>
<s>
3D	O
rendering	O
is	O
handled	O
by	O
EGL	B-Application
.	O
</s>
<s>
Wayland	B-Language
is	O
being	O
developed	O
by	O
several	O
X.Org	O
developers	B-Application
as	O
a	O
prospective	O
replacement	O
for	O
X	B-Operating_System
.	O
</s>
<s>
It	O
works	O
directly	O
with	O
the	O
GPU	B-Architecture
hardware	O
,	O
via	O
DRI	B-Application
.	O
</s>
<s>
Wayland	B-Language
can	O
run	O
an	O
X	B-Operating_System
server	O
as	O
a	O
Wayland	B-Language
compositor	O
,	O
which	O
can	O
be	O
rootless	O
.	O
</s>
<s>
A	O
proprietary	O
port	O
of	O
the	O
Wayland	B-Language
backend	O
to	O
the	O
Raspberry	B-Operating_System
Pi	I-Operating_System
was	O
completed	O
in	O
2013	O
.	O
</s>
<s>
Like	O
Android	B-Application
,	O
Wayland	B-Language
is	O
EGL-based	O
.	O
</s>
<s>
Mir	B-Language
was	O
a	O
project	O
from	O
Canonical	O
Ltd	O
.	O
with	O
goals	O
similar	O
to	O
Wayland	B-Language
.	O
</s>
<s>
Mir	B-Language
was	O
intended	O
to	O
work	O
with	O
mobile	O
devices	O
using	O
ARM	O
chipsets	O
(	O
a	O
stated	O
goal	O
was	O
compatibility	O
with	O
Android	B-Application
device-drivers	O
)	O
as	O
well	O
as	O
x86	O
desktops	O
.	O
</s>
<s>
Like	O
Android	B-Application
,	O
Mir/UnityNext	O
were	O
EGL-based	O
.	O
</s>
<s>
Backwards	O
compatibility	O
with	O
X	B-Operating_System
client-applications	O
was	O
accomplished	O
via	O
Xmir	B-Language
.	O
</s>
<s>
The	O
project	O
has	O
since	O
moved	O
to	O
being	O
a	O
Wayland	B-Language
compositor	O
instead	O
of	O
being	O
an	O
alternative	O
display	B-Device
server	O
.	O
</s>
<s>
Other	O
alternatives	O
attempt	O
to	O
avoid	O
the	O
overhead	O
of	O
X	B-Operating_System
by	O
working	O
directly	O
with	O
the	O
hardware	O
;	O
such	O
projects	O
include	O
DirectFB	B-Application
.	O
</s>
<s>
The	O
Direct	B-Application
Rendering	I-Application
Infrastructure	I-Application
(	O
DRI	B-Application
)	O
provides	O
a	O
kernel-level	O
interface	O
to	O
the	O
framebuffer	B-Algorithm
.	O
</s>
<s>
Additional	O
ways	O
to	O
achieve	O
a	O
functional	O
form	O
of	O
the	O
"	O
network	B-General_Concept
transparency	I-General_Concept
"	O
feature	O
of	O
X	B-Operating_System
,	O
via	O
network	O
transmissibility	O
of	O
graphical	O
services	O
,	O
include	O
:	O
</s>
<s>
Remote	B-Protocol
Desktop	I-Protocol
Protocol	I-Protocol
(	O
RDP	O
)	O
,	O
which	O
is	O
similar	O
to	O
VNC	B-Protocol
in	O
purpose	O
,	O
but	O
originated	O
on	O
Microsoft	O
Windows	O
before	O
being	O
ported	O
to	O
Unix-like	B-Operating_System
systems	I-Operating_System
;	O
cf	O
NX	B-Application
,	O
GotoMyPc	B-Protocol
,	O
etc	O
.	O
</s>
<s>
Several	O
bitmap	O
display	B-Device
systems	O
preceded	O
X	B-Operating_System
.	O
</s>
<s>
From	O
Xerox	O
came	O
the	O
Alto	B-Device
(	O
1973	O
)	O
and	O
the	O
Star	B-Operating_System
(	O
1981	O
)	O
.	O
</s>
<s>
From	O
Apollo	O
Computer	O
came	O
Display	B-Device
Manager	I-Device
(	O
1981	O
)	O
.	O
</s>
<s>
From	O
Apple	O
came	O
the	O
Lisa	B-Device
(	O
1983	O
)	O
and	O
the	O
Macintosh	B-Device
(	O
1984	O
)	O
.	O
</s>
<s>
The	O
Unix	B-Application
world	O
had	O
the	O
Andrew	B-Operating_System
Project	I-Operating_System
(	O
1982	O
)	O
and	O
Rob	O
Pike	O
's	O
Blit	B-Protocol
terminal	B-General_Concept
(	O
1982	O
)	O
.	O
</s>
<s>
Carnegie	O
Mellon	O
University	O
produced	O
a	O
remote-access	O
application	O
called	O
Alto	B-Device
Terminal	B-General_Concept
,	O
that	O
displayed	O
overlapping	O
windows	O
on	O
the	O
Xerox	B-Device
Alto	I-Device
,	O
and	O
made	O
remote	O
hosts	O
(	O
typically	O
DEC	O
VAX	O
systems	O
running	O
Unix	B-Application
)	O
responsible	O
for	O
handling	O
window-exposure	O
events	O
and	O
refreshing	O
window	O
contents	O
as	O
necessary	O
.	O
</s>
<s>
X	B-Operating_System
derives	O
its	O
name	O
as	O
a	O
successor	O
to	O
a	O
pre-1983	O
window	B-Application
system	I-Application
called	O
W	B-Application
(	O
the	O
letter	O
preceding	O
X	B-Operating_System
in	O
the	O
English	O
alphabet	O
)	O
.	O
</s>
<s>
W	B-Application
ran	O
under	O
the	O
V	B-Operating_System
operating	I-Operating_System
system	I-Operating_System
.	O
</s>
<s>
W	B-Application
used	O
a	O
network	O
protocol	O
supporting	O
terminal	B-General_Concept
and	O
graphics	O
windows	O
,	O
the	O
server	O
maintaining	O
display	B-Device
lists	O
.	O
</s>
<s>
The	O
original	O
idea	O
of	O
X	B-Operating_System
emerged	O
at	O
MIT	O
in	O
1984	O
as	O
a	O
collaboration	O
between	O
Jim	O
Gettys	O
(	O
of	O
Project	B-Operating_System
Athena	I-Operating_System
)	O
and	O
Bob	O
Scheifler	O
(	O
of	O
the	O
MIT	O
Laboratory	O
for	O
Computer	O
Science	O
)	O
.	O
</s>
<s>
Scheifler	O
needed	O
a	O
usable	O
display	B-Device
environment	O
for	O
debugging	O
the	O
Argus	O
system	O
.	O
</s>
<s>
Project	B-Operating_System
Athena	I-Operating_System
(	O
a	O
joint	O
project	O
between	O
DEC	O
,	O
MIT	O
and	O
IBM	O
to	O
provide	O
easy	O
access	O
to	O
computing	O
resources	O
for	O
all	O
students	O
)	O
needed	O
a	O
platform-independent	B-Operating_System
graphics	O
system	O
to	O
link	O
together	O
its	O
heterogeneous	O
multiple-vendor	O
systems	O
;	O
the	O
window	B-Application
system	I-Application
then	O
under	O
development	O
in	O
Carnegie	O
Mellon	O
University	O
's	O
Andrew	B-Operating_System
Project	I-Operating_System
did	O
not	O
make	O
licenses	O
available	O
,	O
and	O
no	O
alternatives	O
existed	O
.	O
</s>
<s>
In	O
mid-1983	O
an	O
initial	O
port	O
of	O
W	B-Application
to	O
Unix	B-Application
ran	O
at	O
one-fifth	O
of	O
its	O
speed	O
under	O
V	B-Operating_System
;	O
in	O
May	O
1984	O
,	O
Scheifler	O
replaced	O
the	O
synchronous	O
protocol	O
of	O
W	B-Application
with	O
an	O
asynchronous	O
protocol	O
and	O
the	O
display	B-Device
lists	O
with	O
immediate	O
mode	O
graphics	O
to	O
make	O
X	B-Operating_System
version	O
1	O
.	O
</s>
<s>
X	B-Operating_System
became	O
the	O
first	O
windowing	B-Application
system	I-Application
environment	O
to	O
offer	O
true	O
hardware	O
independence	O
and	O
vendor	O
independence	O
.	O
</s>
<s>
Scheifler	O
,	O
Gettys	O
and	O
Ron	O
Newman	O
set	O
to	O
work	O
and	O
X	B-Operating_System
progressed	O
rapidly	O
.	O
</s>
<s>
DEC	O
,	O
then	O
preparing	O
to	O
release	O
its	O
first	O
Ultrix	B-Operating_System
workstation	O
,	O
judged	O
X	B-Operating_System
the	O
only	O
windowing	B-Application
system	I-Application
likely	O
to	O
become	O
available	O
in	O
time	O
.	O
</s>
<s>
DEC	O
engineers	O
ported	O
X6	O
to	O
DEC	O
's	O
QVSS	O
display	B-Device
on	O
MicroVAX	B-Device
.	O
</s>
<s>
In	O
the	O
second	O
quarter	O
of	O
1985	O
,	O
X	B-Operating_System
acquired	O
color	B-Device
support	O
to	O
function	O
in	O
the	O
DEC	O
VAXstation-II/GPX	O
,	O
forming	O
what	O
became	O
version	O
9	O
.	O
</s>
<s>
A	O
group	O
at	O
Brown	O
University	O
ported	O
version	O
9	O
to	O
the	O
IBM	B-Device
RT	I-Device
PC	I-Device
,	O
but	O
problems	O
with	O
reading	O
unaligned	O
data	O
on	O
the	O
RT	O
forced	O
an	O
incompatible	O
protocol	O
change	O
,	O
leading	O
to	O
version	O
10	O
in	O
late	O
1985	O
.	O
</s>
<s>
By	O
1986	O
,	O
outside	O
organizations	O
had	O
begun	O
asking	O
for	O
X	B-Operating_System
.	O
X10R2	O
was	O
released	O
in	O
January	O
1986	O
,	O
then	O
X10R3	O
in	O
February	O
1986	O
.	O
</s>
<s>
Although	O
MIT	O
had	O
licensed	O
X6	O
to	O
some	O
outside	O
groups	O
for	O
a	O
fee	O
,	O
it	O
decided	O
at	O
this	O
time	O
to	O
license	O
X10R3	O
and	O
future	O
versions	O
under	O
what	O
became	O
known	O
as	O
the	B-License
MIT	I-License
License	I-License
,	O
intending	O
to	O
popularize	O
X	B-Operating_System
further	O
and	O
,	O
in	O
return	O
,	O
hoping	O
that	O
many	O
more	O
applications	O
would	O
become	O
available	O
.	O
</s>
<s>
Other	O
groups	O
ported	O
X10	O
to	O
Apollo	O
and	O
to	O
Sun	O
workstations	O
and	O
even	O
to	O
the	O
IBM	B-Operating_System
PC/AT	I-Operating_System
.	O
</s>
<s>
Demonstrations	O
of	O
the	O
first	O
commercial	O
application	O
for	O
X	B-Operating_System
(	O
a	O
mechanical	O
computer-aided	O
engineering	O
system	O
from	O
Cognition	O
Inc	O
.	O
that	O
ran	O
on	O
VAXes	O
and	O
remotely	O
displayed	O
on	O
PCs	B-Device
running	O
an	O
X	B-Operating_System
server	O
ported	O
by	O
Jim	O
Fulton	O
and	O
Jan	O
Hardenbergh	O
)	O
took	O
place	O
at	O
the	O
Autofact	O
trade	O
show	O
at	O
that	O
time	O
.	O
</s>
<s>
Attempts	O
were	O
made	O
to	O
enable	O
X	B-Operating_System
servers	I-Operating_System
as	O
real-time	O
collaboration	O
devices	O
,	O
much	O
as	O
Virtual	B-Protocol
Network	I-Protocol
Computing	I-Protocol
(	O
VNC	B-Protocol
)	O
would	O
later	O
allow	O
a	O
desktop	O
to	O
be	O
shared	O
.	O
</s>
<s>
One	O
such	O
early	O
effort	O
was	O
Philip	O
J	O
.	O
Gust	O
's	O
SharedX	B-Application
tool	O
.	O
</s>
<s>
Although	O
X10	O
offered	O
interesting	O
and	O
powerful	O
functionality	O
,	O
it	O
had	O
become	O
obvious	O
that	O
the	O
X	B-Operating_System
protocol	O
could	O
use	O
a	O
more	O
hardware-neutral	O
redesign	O
before	O
it	O
became	O
too	O
widely	O
deployed	O
,	O
but	O
MIT	O
alone	O
would	O
not	O
have	O
the	O
resources	O
available	O
for	O
such	O
a	O
complete	O
redesign	O
.	O
</s>
<s>
Smokey	O
Wallace	O
of	O
DEC	O
WSL	O
and	O
Jim	O
Gettys	O
proposed	O
that	O
DEC	O
WSL	O
build	O
X11	B-Operating_System
and	O
make	O
it	O
freely	O
available	O
under	O
the	O
same	O
terms	O
as	O
X9	O
and	O
X10	O
.	O
</s>
<s>
Alpha	O
testing	O
of	O
the	O
software	O
started	O
in	O
February	O
1987	O
,	O
beta-testing	O
in	O
May	O
;	O
the	O
release	O
of	O
X11	B-Operating_System
finally	O
occurred	O
on	O
15	O
September	O
1987	O
.	O
</s>
<s>
The	O
X11	B-Operating_System
protocol	O
design	O
,	O
led	O
by	O
Scheifler	O
,	O
was	O
extensively	O
discussed	O
on	O
open	O
mailing	O
lists	O
on	O
the	O
nascent	O
Internet	O
that	O
were	O
bridged	O
to	O
USENET	O
newsgroups	O
.	O
</s>
<s>
Gettys	O
moved	O
to	O
California	O
to	O
help	O
lead	O
the	O
X11	B-Operating_System
development	O
work	O
at	O
WSL	O
from	O
DEC	O
's	O
Systems	O
Research	O
Center	O
,	O
where	O
Phil	O
Karlton	O
and	O
Susan	O
Angebrandt	O
led	O
the	O
X11	B-Operating_System
sample	O
server	O
design	O
and	O
implementation	O
.	O
</s>
<s>
X	B-Operating_System
therefore	O
represents	O
one	O
of	O
the	O
first	O
very	O
large-scale	O
distributed	O
free	B-Application
and	I-Application
open	I-Application
source	I-Application
software	I-Application
projects	O
.	O
</s>
<s>
By	O
the	O
late	O
1980s	O
X	B-Operating_System
was	O
,	O
Simson	O
Garfinkel	O
wrote	O
in	O
1989	O
,	O
"	O
Athena	O
's	O
most	O
important	O
single	O
achievement	O
to	O
date	O
"	O
.	O
</s>
<s>
Gettys	O
joined	O
the	O
design	O
team	O
for	O
the	O
VAXstation	B-Device
2000	I-Device
to	O
ensure	O
that	O
X	B-Operating_System
—	O
which	O
DEC	O
called	O
DECwindows	B-Application
—	O
would	O
run	O
on	O
it	O
,	O
and	O
the	O
company	O
assigned	O
1,200	O
employees	O
to	O
port	O
X	B-Operating_System
to	O
both	O
Ultrix	B-Operating_System
and	O
VMS	B-Operating_System
.	O
</s>
<s>
In	O
1987	O
,	O
with	O
the	O
success	O
of	O
X11	B-Operating_System
becoming	O
apparent	O
,	O
MIT	O
wished	O
to	O
relinquish	O
the	O
stewardship	O
of	O
X	B-Operating_System
,	O
but	O
at	O
a	O
June	O
1987	O
meeting	O
with	O
nine	O
vendors	O
,	O
the	O
vendors	O
told	O
MIT	O
that	O
they	O
believed	O
in	O
the	O
need	O
for	O
a	O
neutral	O
party	O
to	O
keep	O
X	B-Operating_System
from	O
fragmenting	O
in	O
the	O
marketplace	O
.	O
</s>
<s>
In	O
January	O
1988	O
,	O
the	O
MIT	B-License
X	I-License
Consortium	O
formed	O
as	O
a	O
non-profit	O
vendor	O
group	O
,	O
with	O
Scheifler	O
as	O
director	O
,	O
to	O
direct	O
the	O
future	O
development	O
of	O
X	B-Operating_System
in	O
a	O
neutral	O
atmosphere	O
inclusive	O
of	O
commercial	O
and	O
educational	O
interests	O
.	O
</s>
<s>
Jim	O
Fulton	O
joined	O
in	O
January	O
1988	O
and	O
Keith	O
Packard	O
in	O
March	O
1988	O
as	O
senior	O
developers	B-Application
,	O
with	O
Jim	O
focusing	O
on	O
Xlib	B-Language
,	O
fonts	O
,	O
window	B-Application
managers	I-Application
,	O
and	O
utilities	O
;	O
and	O
Keith	O
re-implementing	O
the	O
server	O
.	O
</s>
<s>
Donna	O
Converse	O
,	O
Chris	O
D	O
.	O
Peterson	O
,	O
and	O
Stephen	O
Gildea	O
joined	O
later	O
that	O
year	O
,	O
focusing	O
on	O
toolkits	O
and	O
widget	B-Library
sets	I-Library
,	O
working	O
closely	O
with	O
Ralph	O
Swick	O
of	O
MIT	O
Project	B-Operating_System
Athena	I-Operating_System
.	O
</s>
<s>
The	O
MIT	B-License
X	I-License
Consortium	O
produced	O
several	O
significant	O
revisions	O
to	O
X11	B-Operating_System
,	O
the	O
first	O
(	O
Release	O
2X11R2	O
)	O
in	O
February	O
1988	O
.	O
</s>
<s>
Jay	O
Hersh	O
joined	O
the	O
staff	O
in	O
January	O
1991	O
to	O
work	O
on	O
the	O
PEX	B-Library
and	O
X113D	O
functionality	O
.	O
</s>
<s>
He	O
was	O
followed	O
soon	O
after	O
by	O
Ralph	O
Mor	O
(	O
who	O
also	O
worked	O
on	O
PEX	B-Library
)	O
and	O
Dave	O
Sternlicht	O
.	O
</s>
<s>
In	O
1993	O
,	O
as	O
the	O
MIT	B-License
X	I-License
Consortium	O
prepared	O
to	O
depart	O
from	O
MIT	O
,	O
the	O
staff	O
were	O
joined	O
by	O
R	O
.	O
Gary	O
Cutbill	O
,	O
Kaleb	O
Keithley	O
,	O
and	O
David	O
Wiggins	O
.	O
</s>
<s>
In	O
1993	O
,	O
the	O
X	B-Operating_System
Consortium	O
,	O
Inc	O
.	O
(	O
a	O
non-profit	O
corporation	O
)	O
formed	O
as	O
the	O
successor	O
to	O
the	O
MIT	B-License
X	I-License
Consortium	O
.	O
</s>
<s>
It	O
released	O
X11R6	B-Operating_System
on	O
16	O
May	O
1994	O
.	O
</s>
<s>
In	O
1995	O
it	O
took	O
on	O
the	O
development	O
of	O
the	O
Motif	B-Application
toolkit	I-Application
and	O
of	O
the	O
Common	B-Application
Desktop	I-Application
Environment	I-Application
for	O
Unix	B-Application
systems	I-Application
.	O
</s>
<s>
The	O
X	B-Operating_System
Consortium	O
dissolved	O
at	O
the	O
end	O
of	O
1996	O
,	O
producing	O
a	O
final	O
revision	O
,	O
X11R6.3	O
,	O
and	O
a	O
legacy	O
of	O
increasing	O
commercial	O
influence	O
in	O
the	O
development	O
.	O
</s>
<s>
In	O
January	O
1997	O
,	O
the	O
X	B-Operating_System
Consortium	O
passed	O
stewardship	O
of	O
X	B-Operating_System
to	O
The	B-Application
Open	I-Application
Group	I-Application
,	O
a	O
vendor	O
group	O
formed	O
in	O
early	O
1996	O
by	O
the	O
merger	O
of	O
the	O
Open	B-Application
Software	I-Application
Foundation	I-Application
and	O
X/Open	O
.	O
</s>
<s>
The	B-Application
Open	I-Application
Group	I-Application
released	O
X11R6.4	O
in	O
early	O
1998	O
.	O
</s>
<s>
Controversially	O
,	O
X11R6.4	O
departed	O
from	O
the	O
traditional	O
liberal	O
licensing	O
terms	O
,	O
as	O
the	B-Application
Open	I-Application
Group	I-Application
sought	O
to	O
assure	O
funding	O
for	O
the	O
development	O
of	O
X	B-Operating_System
,	O
and	O
specifically	O
cited	O
XFree86	B-Device
as	O
not	O
significantly	O
contributing	O
to	O
X	B-Operating_System
.	O
</s>
<s>
The	O
new	O
terms	O
would	O
have	O
made	O
X	B-Operating_System
no	O
longer	O
free	B-Application
software	I-Application
:	O
zero-cost	O
for	O
noncommercial	O
use	O
,	O
but	O
a	O
fee	O
otherwise	O
.	O
</s>
<s>
After	O
XFree86	B-Device
seemed	O
poised	O
to	O
fork	B-Application
,	O
the	B-Application
Open	I-Application
Group	I-Application
relicensed	O
X11R6.4	O
under	O
the	O
traditional	O
license	O
in	O
September	O
1998	O
.	O
</s>
<s>
The	B-Application
Open	I-Application
Group	I-Application
's	O
last	O
release	O
came	O
as	O
X11R6.4	O
patch	O
3	O
.	O
</s>
<s>
XFree86	B-Device
originated	O
in	O
1992	O
from	O
the	O
X386	B-Device
server	O
for	O
IBM	O
PC	B-Device
compatibles	O
included	O
with	O
X11R5	B-Operating_System
in	O
1991	O
,	O
written	O
by	O
Thomas	O
Roell	O
and	O
Mark	O
W	B-Application
.	O
Snitily	O
and	O
donated	O
to	O
the	O
MIT	B-License
X	I-License
Consortium	O
by	O
Snitily	O
Graphics	O
Consulting	O
Services	O
(	O
SGCS	O
)	O
.	O
</s>
<s>
XFree86	B-Device
evolved	O
over	O
time	O
from	O
just	O
one	O
port	O
of	O
X	B-Operating_System
to	O
the	O
leading	O
and	O
most	O
popular	O
implementation	O
and	O
the	O
de	O
facto	O
standard	O
of	O
X	B-Operating_System
's	O
development	O
.	O
</s>
<s>
In	O
May	O
1999	O
,	O
The	B-Application
Open	I-Application
Group	I-Application
formed	O
X.Org	O
.	O
</s>
<s>
X.Org	O
supervised	O
the	O
release	O
of	O
versions	O
X11R6.5.1	O
onward	O
.	O
</s>
<s>
X	B-Operating_System
development	O
at	O
this	O
time	O
had	O
become	O
moribund	O
;	O
most	O
technical	O
innovation	O
since	O
the	O
X	B-Operating_System
Consortium	O
had	O
dissolved	O
had	O
taken	O
place	O
in	O
the	O
XFree86	B-Device
project	O
.	O
</s>
<s>
In	O
1999	O
,	O
the	O
XFree86	B-Device
team	O
joined	O
X.Org	O
as	O
an	O
honorary	O
(	O
non-paying	O
)	O
member	O
,	O
encouraged	O
by	O
various	O
hardware	O
companies	O
interested	O
in	O
using	O
XFree86	B-Device
with	O
Linux	B-Application
and	O
in	O
its	O
status	O
as	O
the	O
most	O
popular	O
version	O
of	O
X	B-Operating_System
.	O
</s>
<s>
By	O
2003	O
,	O
while	O
the	O
popularity	O
of	O
Linux	B-Application
(	O
and	O
hence	O
the	O
installed	O
base	O
of	O
X	B-Operating_System
)	O
surged	O
,	O
X.Org	O
remained	O
inactive	O
,	O
and	O
active	O
development	O
took	O
place	O
largely	O
within	O
XFree86	B-Device
.	O
</s>
<s>
However	O
,	O
considerable	O
dissent	O
developed	O
within	O
XFree86	B-Device
.	O
</s>
<s>
The	O
XFree86	B-Device
project	O
suffered	O
from	O
a	O
perception	O
of	O
a	O
far	O
too	O
cathedral-like	O
development	O
model	O
;	O
developers	B-Application
could	O
not	O
get	O
CVS	B-Application
commit	O
access	O
and	O
vendors	O
had	O
to	O
maintain	O
extensive	O
patch	O
sets	O
.	O
</s>
<s>
In	O
March	O
2003	O
,	O
the	O
XFree86	B-Device
organization	O
expelled	O
Keith	O
Packard	O
,	O
who	O
had	O
joined	O
XFree86	B-Device
after	O
the	O
end	O
of	O
the	O
original	O
MIT	B-License
X	I-License
Consortium	O
,	O
with	O
considerable	O
ill	O
feeling	O
.	O
</s>
<s>
X.Org	O
and	O
XFree86	B-Device
began	O
discussing	O
a	O
reorganisation	O
suited	O
to	O
properly	O
nurturing	O
the	O
development	O
of	O
X	B-Operating_System
.	O
Jim	O
Gettys	O
had	O
been	O
pushing	O
strongly	O
for	O
an	O
open	O
development	O
model	O
since	O
at	O
least	O
2000	O
.	O
</s>
<s>
Gettys	O
,	O
Packard	O
and	O
several	O
others	O
began	O
discussing	O
in	O
detail	O
the	O
requirements	O
for	O
the	O
effective	O
governance	O
of	O
X	B-Operating_System
with	O
open	O
development	O
.	O
</s>
<s>
Finally	O
,	O
in	O
an	O
echo	O
of	O
the	O
X11R6.4	O
licensing	O
dispute	O
,	O
XFree86	B-Device
released	O
version	O
4.4	O
in	O
February	O
2004	O
under	O
a	O
more	O
restrictive	O
license	O
which	O
many	O
projects	O
relying	O
on	O
X	B-Operating_System
found	O
unacceptable	O
.	O
</s>
<s>
The	O
added	O
clause	O
to	O
the	O
license	O
was	O
based	O
on	O
the	O
original	O
BSD	B-Operating_System
license	I-Operating_System
's	O
advertising	O
clause	O
,	O
which	O
was	O
viewed	O
by	O
the	B-Operating_System
Free	I-Operating_System
Software	I-Operating_System
Foundation	I-Operating_System
and	O
Debian	O
as	O
incompatible	O
with	O
the	O
GNU	B-License
General	I-License
Public	I-License
License	I-License
.	O
</s>
<s>
Other	O
groups	O
saw	O
it	O
as	O
against	O
the	O
spirit	O
of	O
the	O
original	O
X	B-Operating_System
.	O
Theo	O
de	O
Raadt	O
of	O
OpenBSD	B-Operating_System
,	O
for	O
instance	O
,	O
threatened	O
to	O
fork	B-Application
XFree86	B-Device
citing	O
license	O
concerns	O
.	O
</s>
<s>
The	O
license	O
issue	O
,	O
combined	O
with	O
the	O
difficulties	O
in	O
getting	O
changes	O
in	O
,	O
left	O
many	O
feeling	O
the	O
time	O
was	O
ripe	O
for	O
a	O
fork	B-Application
.	O
</s>
<s>
In	O
early	O
2004	O
,	O
various	O
people	O
from	O
X.Org	O
and	O
freedesktop.org	O
formed	O
the	O
X.Org	B-Application
Foundation	I-Application
,	O
and	O
the	B-Application
Open	I-Application
Group	I-Application
gave	O
it	O
control	O
of	O
the	O
x.org	O
domain	O
name	O
.	O
</s>
<s>
This	O
marked	O
a	O
radical	O
change	O
in	O
the	O
governance	O
of	O
X	B-Operating_System
.	O
</s>
<s>
Whereas	O
the	O
stewards	O
of	O
X	B-Operating_System
since	O
1988	O
(	O
including	O
the	O
prior	O
X.Org	O
)	O
had	O
been	O
vendor	O
organizations	O
,	O
the	O
Foundation	O
was	O
led	O
by	O
software	B-Application
developers	I-Application
and	O
used	O
community	O
development	O
based	O
on	O
the	O
bazaar	O
model	O
,	O
which	O
relies	O
on	O
outside	O
involvement	O
.	O
</s>
<s>
Several	O
major	O
corporations	O
such	O
as	O
Hewlett-Packard	O
currently	O
support	O
the	O
X.Org	B-Application
Foundation	I-Application
.	O
</s>
<s>
The	O
Foundation	O
takes	O
an	O
oversight	O
role	O
over	O
X	B-Operating_System
development	O
:	O
technical	O
decisions	O
are	O
made	O
on	O
their	O
merits	O
by	O
achieving	O
rough	O
consensus	O
among	O
community	O
members	O
.	O
</s>
<s>
Technical	O
decisions	O
are	O
not	O
made	O
by	O
the	O
board	O
of	O
directors	O
;	O
in	O
this	O
sense	O
,	O
it	O
is	O
strongly	O
modelled	O
on	O
the	O
technically	O
non-interventionist	O
GNOME	B-Language
Foundation	I-Language
.	O
</s>
<s>
The	O
Foundation	O
employs	O
no	O
developers	B-Application
.	O
</s>
<s>
The	O
Foundation	O
released	O
X11R6.7	O
,	O
the	O
X.Org	B-Operating_System
Server	I-Operating_System
,	O
in	O
April	O
2004	O
,	O
based	O
on	O
XFree86	B-Device
4.4RC2	O
with	O
X11R6.6	O
changes	O
merged	O
.	O
</s>
<s>
Gettys	O
and	O
Packard	O
had	O
taken	O
the	O
last	O
version	O
of	O
XFree86	B-Device
under	O
the	O
old	O
license	O
and	O
,	O
by	O
making	O
a	O
point	O
of	O
an	O
open	O
development	O
model	O
and	O
retaining	O
GPL	B-License
compatibility	O
,	O
brought	O
many	O
of	O
the	O
old	O
XFree86	B-Device
developers	B-Application
on	O
board	O
.	O
</s>
<s>
While	O
X11	B-Operating_System
had	O
received	O
extensions	O
such	O
as	O
OpenGL	O
support	O
during	O
the	O
1990s	O
,	O
its	O
architecture	O
had	O
remained	O
fundamentally	O
unchanged	O
during	O
the	O
decade	O
.	O
</s>
<s>
In	O
the	O
early	O
part	O
of	O
the	O
2000s	O
,	O
however	O
,	O
it	O
was	O
overhauled	O
to	O
resolve	O
a	O
number	O
of	O
problems	O
that	O
had	O
surfaced	O
over	O
the	O
years	O
,	O
including	O
a	O
"	O
flawed	O
"	O
font	O
architecture	O
,	O
a	O
2D	O
graphics	O
system	O
"	O
which	O
had	O
always	O
been	O
intended	O
to	O
be	O
augmented	O
and/or	O
replaced	O
"	O
,	O
and	O
latency	B-Protocol
issues	O
.	O
</s>
<s>
X11R6.8	O
came	O
out	O
in	O
September	O
2004	O
.	O
</s>
<s>
It	O
added	O
significant	O
new	O
features	O
,	O
including	O
preliminary	O
support	O
for	O
translucent	O
windows	O
and	O
other	O
sophisticated	O
visual	O
effects	O
,	O
screen	O
magnifiers	O
and	O
thumbnailers	O
,	O
and	O
facilities	O
to	O
integrate	O
with	O
3D	O
immersive	O
display	B-Device
systems	O
such	O
as	O
Sun	O
's	O
Project	B-Language
Looking	I-Language
Glass	I-Language
and	O
the	O
Croquet	B-Protocol
project	I-Protocol
.	O
</s>
<s>
External	O
applications	O
called	O
compositing	B-Operating_System
window	I-Operating_System
managers	I-Operating_System
provide	O
policy	O
for	O
the	O
visual	O
appearance	O
.	O
</s>
<s>
On	O
21	O
December	O
2005	O
,	O
X.Org	O
released	O
X11R6.9	O
,	O
the	O
monolithic	O
source	O
tree	O
for	O
legacy	O
users	O
,	O
and	O
X11R7.0	O
,	O
the	O
same	O
source	O
code	O
separated	O
into	O
independent	O
modules	O
,	O
each	O
maintainable	O
in	O
separate	O
projects	O
.	O
</s>
<s>
The	O
Foundation	O
released	O
X11R7.1	B-Operating_System
on	O
22	O
May	O
2006	O
,	O
about	O
four	O
months	O
after	O
7.0	O
,	O
with	O
considerable	O
feature	O
improvements	O
.	O
</s>
<s>
XFree86	B-Device
development	O
continued	O
for	O
a	O
few	O
more	O
years	O
,	O
4.8.0	O
being	O
released	O
on	O
15	O
December	O
2008	O
.	O
</s>
<s>
The	O
proper	O
names	O
for	O
the	O
system	O
are	O
listed	O
in	O
the	O
manual	O
page	O
as	O
X	B-Operating_System
;	O
X	B-Operating_System
Window	I-Operating_System
System	I-Operating_System
;	O
X	B-Operating_System
Version	O
11	O
;	O
X	B-Operating_System
Window	I-Operating_System
System	I-Operating_System
,	O
Version	O
11	O
;	O
or	O
X11	B-Operating_System
.	O
</s>
<s>
The	O
term	O
"	O
X-Windows	B-Operating_System
"	O
(	O
in	O
the	O
manner	O
of	O
the	O
subsequently	O
released	O
"	O
Microsoft	O
Windows	O
"	O
)	O
is	O
not	O
officially	O
endorsedwith	O
X	B-Operating_System
Consortium	O
release	O
manager	O
Matt	O
Landau	O
stating	O
in	O
1993	O
,	O
"	O
There	O
is	O
no	O
such	O
thing	O
as	O
'	O
X	B-Operating_System
Windows	I-Operating_System
 '	O
or	O
'	O
X	B-Operating_System
Window	I-Operating_System
 '	O
,	O
despite	O
the	O
repeated	O
misuse	O
of	O
the	O
forms	O
by	O
the	O
trade	O
rags	O
"	O
though	O
it	O
has	O
been	O
in	O
common	O
informal	O
use	O
since	O
early	O
in	O
the	O
history	O
of	O
X	B-Operating_System
and	O
has	O
been	O
used	O
deliberately	O
for	O
provocative	O
effect	O
,	O
for	O
example	O
in	O
the	O
Unix-Haters	O
Handbook	O
.	O
</s>
<s>
The	O
X	B-Operating_System
Window	I-Operating_System
System	I-Operating_System
has	O
nuanced	O
usage	O
of	O
a	O
number	O
of	O
terms	O
when	O
compared	O
to	O
common	O
usage	O
,	O
particularly	O
"	O
display	B-Device
"	O
and	O
"	O
screen	O
"	O
,	O
a	O
subset	O
of	O
which	O
is	O
given	O
here	O
for	O
convenience	O
:	O
</s>
<s>
monitor	O
A	O
physical	O
device	O
such	O
as	O
a	O
CRT	B-Device
or	O
a	O
flat	O
screen	O
computer	B-Device
display	I-Device
.	O
</s>
<s>
screen	O
An	O
area	O
into	O
which	O
graphics	O
may	O
be	O
rendered	O
,	O
either	O
through	O
software	O
alone	O
into	O
system	O
memory	O
as	O
with	O
VNC	B-Protocol
,	O
or	O
within	O
a	O
graphics	O
device	O
,	O
some	O
of	O
which	O
can	O
render	O
into	O
more	O
than	O
one	O
screen	O
simultaneously	O
,	O
either	O
viewable	O
simultaneously	O
or	O
interchangeably	O
.	O
</s>
<s>
An	O
effect	O
simulated	O
by	O
a	O
window	B-Application
manager	I-Application
by	O
maintaining	O
window	O
position	O
information	O
in	O
a	O
larger	O
coordinate	O
system	O
than	O
the	O
screen	O
and	O
allowing	O
panning	O
by	O
simply	O
moving	O
the	O
windows	O
in	O
response	O
to	O
the	O
user	O
.	O
</s>
<s>
display	B-Device
A	O
collection	O
of	O
screens	O
,	O
often	O
involving	O
multiple	O
monitors	O
,	O
generally	O
configured	O
to	O
allow	O
the	O
mouse	O
to	O
move	O
the	O
pointer	O
to	O
any	O
position	O
within	O
them	O
.	O
</s>
<s>
Linux-based	O
workstations	O
are	O
usually	O
capable	O
of	O
having	O
multiple	O
displays	O
,	O
among	O
which	O
the	O
user	O
can	O
switch	O
with	O
a	O
special	O
keyboard	O
combination	O
such	O
as	O
control-alt-function-key	O
,	O
simultaneously	O
flipping	O
all	O
the	O
monitors	O
from	O
showing	O
the	O
screens	O
of	O
one	O
display	B-Device
to	O
the	O
screens	O
in	O
another	O
.	O
</s>
<s>
The	O
term	O
"	O
display	B-Device
"	O
should	O
not	O
be	O
confused	O
with	O
the	O
more	O
specialized	O
jargon	O
"	O
Zaphod	B-Operating_System
display	I-Operating_System
"	O
.	O
</s>
<s>
The	O
latter	O
is	O
a	O
rare	O
configuration	O
allowing	O
multiple	O
users	O
of	O
a	O
single	O
computer	O
to	O
each	O
have	O
an	O
independent	O
set	O
of	O
display	B-Device
,	O
mouse	O
,	O
and	O
keyboard	O
,	O
as	O
though	O
they	O
were	O
using	O
separate	O
computers	O
,	O
but	O
at	O
a	O
lower	O
per-seat	O
cost	O
.	O
</s>
<s>
VersionRelease	O
dateMost	O
important	O
changesFirst	O
use	O
of	O
the	O
name	O
"	O
X	B-Operating_System
"	O
;	O
fundamental	O
changes	O
distinguishing	O
the	O
product	O
from	O
W.First	O
version	O
licensed	O
to	O
a	O
handful	O
of	O
outside	O
companies.Color	O
.	O
</s>
<s>
First	O
release	O
under	O
MIT	O
License.IBM	O
RT	O
PC	O
,	O
AT	O
(	O
running	O
DOS	B-Device
)	O
,	O
and	O
others.First	O
freely	O
redistributable	O
X	B-Operating_System
release	O
.	O
</s>
<s>
uwm	B-Device
made	O
standard	O
window	O
manager.Last	O
version	O
of	O
X10.First	O
release	O
of	O
the	O
current	O
protocol.First	O
X	B-Operating_System
Consortium	O
release.The	O
X	B-Operating_System
Window	I-Operating_System
System	I-Operating_System
:	O
History	O
and	O
Architecture	O
1	O
September	O
1999XDM.XDMCP	O
,	O
twm	B-Language
(	O
from	O
the	O
beginning	O
known	O
as	O
Tom	B-Language
's	I-Language
window	I-Language
manager	I-Language
)	O
brought	O
in	O
as	O
standard	O
window	B-Application
manager	I-Application
,	O
application	O
improvements	O
,	O
shape	B-Device
extension	I-Device
,	O
new	O
fonts.X386	O
1.2	O
,	O
PEX	B-Library
,	O
Xcms	O
(	O
color	B-Device
management	O
)	O
,	O
font	B-Application
server	I-Application
,	O
X	B-Operating_System
video	O
extension.ICCCM	O
v2.0	O
;	O
Inter-Client	O
Exchange	O
;	O
X	B-Operating_System
Session	O
Management	O
;	O
X	B-Operating_System
Synchronization	O
extension	O
;	O
X	B-Application
Image	I-Application
extension	I-Application
;	O
XTEST	O
extension	O
;	O
X	B-Operating_System
Input	O
;	O
X	B-Operating_System
Big	O
Requests	O
;	O
XC-MISC	O
;	O
XFree86	B-Device
changes.X	O
Double	O
Buffer	O
extension	O
;	O
X	B-Application
keyboard	I-Application
extension	I-Application
;	O
X	B-Operating_System
Record	O
extension.Web	O
functionality	O
,	O
LBX	B-Device
.	O
</s>
<s>
Last	O
X	B-Operating_System
Consortium	O
release	O
.	O
</s>
<s>
X11R6.2	O
is	O
the	O
tag	O
for	O
a	O
subset	O
of	O
X11R6.3	O
(	O
Broadway	O
)	O
with	O
the	O
only	O
new	O
features	O
over	O
R6.1	O
being	O
XPrint	O
and	O
the	O
Xlib	B-Language
implementation	O
of	O
vertical	O
writing	O
and	O
user-defined	O
character	O
support.XFree86	O
and	O
X11R6.3	O
December	O
1999Xinerama.The	O
Open	O
Group	O
Announces	O
Internet-Ready	O
X	B-Operating_System
Window	I-Operating_System
System	I-Operating_System
X11R6.4	O
31	O
March	O
1998Internal	O
X.org	O
release	O
;	O
not	O
made	O
publicly	O
available.Bug	O
fixes	O
,	O
XFree86	B-Device
changes.First	O
X.Org	B-Application
Foundation	I-Application
release	O
,	O
incorporating	O
XFree86	B-Device
4.4rc2	O
.	O
</s>
<s>
Removal	O
of	O
XIE	B-Application
,	O
PEX	B-Library
and	O
libxml2.X.Org	O
Foundation	O
releases	O
X	B-Operating_System
Window	I-Operating_System
System	I-Operating_System
X11R6.7	O
7	O
April	O
2004Window	O
translucency	O
,	O
XDamage	O
,	O
Distributed	O
Multihead	O
X	B-Operating_System
,	O
XFixes	B-Device
,	O
Composite	O
,	O
XEvIE.Security	O
fix	O
in	O
libxpm.Bug	O
fixes	O
,	O
driver	O
updates.XServer	O
1.0.1	O
,	O
EXA	B-Library
,	O
major	O
source	O
code	O
refactoring.Changes	O
Since	O
R6.8	O
21	O
October	O
2005	O
From	O
the	O
same	O
source-code	O
base	O
,	O
the	O
modular	O
autotooled	B-Application
version	O
became	O
7.0	O
and	O
the	O
monolithic	O
imake	B-Application
version	O
was	O
frozen	O
at	O
6.9.XServer	O
1.1.0	O
,	O
EXA	B-Library
enhancements	O
,	O
KDrive	B-Operating_System
integrated	O
,	O
AIGLX	B-Application
,	O
OS	O
and	O
platform	O
support	O
enhancements.Release	O
Notes	O
for	O
X11R7.1	B-Operating_System
22	O
May	O
2006XServer	O
1.2.0	O
,	O
Removal	O
of	O
LBX	B-Device
and	O
the	O
built-in	O
keyboard	O
driver	O
,	O
X-ACE	O
,	O
XCB	B-Language
,	O
autoconfig	O
improvements	O
,	O
cleanups.The	O
X.Org	B-Application
Foundation	I-Application
released	O
7.2.0	O
(	O
aka	O
X11R7.2	O
)	O
15	O
February	O
2007XServer	O
1.4.0	O
,	O
Input	O
hotplug	B-Device
,	O
output	O
hotplug	B-Device
(	O
RandR	O
1.2	O
)	O
,	O
DTrace	B-Application
probes	O
,	O
PCI	B-Protocol
domain	O
support.X	O
server	O
version	O
1.4	O
release	O
plans	O
.	O
</s>
<s>
Retrieved	O
25	O
August	O
2007.XServer	O
1.5.1	O
,	O
XACE	O
,	O
PCI-rework	O
,	O
EXA	B-Library
speed-ups	O
,	O
_X_EXPORT	O
,	O
GLX	B-Device
1.4	O
,	O
faster	O
startup	O
and	O
shutdown.XServer	O
1.7.1	O
,	O
Xi	O
2	O
,	O
XGE	O
,	O
E-EDID	O
support	O
,	O
RandR	O
1.3	O
,	O
MPX	B-Device
,	O
predictable	O
pointer	O
acceleration	O
,	O
DRI2	B-Application
memory	O
manager	O
,	O
SELinux	O
security	O
module	O
,	O
further	O
removal	O
of	O
obsolete	O
libraries	O
and	O
extensions.X	O
Server	O
1.9.3	O
,	O
XCB	B-Language
requirement.X	O
Server	O
1.12.2	O
;	O
Sync	O
extension	O
3.1	O
:	O
adds	O
Fence	O
object	O
support	O
;	O
Xi	O
2.2	O
multitouch	O
support	O
;	O
XFixes	B-Device
5.0	O
:	O
Pointer	O
Barriers	O
.	O
</s>
<s>
On	O
the	O
prospect	O
of	O
future	O
versions	O
,	O
the	O
X.org	O
website	O
states	O
:	O
</s>
