<s>
The	O
Linux	B-Application
console	I-Application
is	O
a	O
system	B-Device
console	I-Device
internal	O
to	O
the	O
Linux	B-Operating_System
kernel	I-Operating_System
.	O
</s>
<s>
A	O
system	B-Device
console	I-Device
is	O
the	O
device	O
which	O
receives	O
all	O
kernel	B-Operating_System
messages	O
and	O
warnings	O
and	O
which	O
allows	O
logins	O
in	O
single	O
user	B-Operating_System
mode	I-Operating_System
.	O
</s>
<s>
The	O
Linux	B-Application
console	I-Application
provides	O
a	O
way	O
for	O
the	O
kernel	B-Operating_System
and	O
other	O
processes	O
to	O
send	O
text	O
output	O
to	O
the	O
user	O
,	O
and	O
to	O
receive	O
text	O
input	O
from	O
the	O
user	O
.	O
</s>
<s>
The	O
user	O
typically	O
enters	O
text	O
with	O
a	O
computer	B-Device
keyboard	I-Device
and	O
reads	O
the	O
output	O
text	O
on	O
a	O
computer	B-Device
monitor	I-Device
.	O
</s>
<s>
The	O
Linux	B-Operating_System
kernel	I-Operating_System
supports	O
virtual	B-Application
consoles	I-Application
–	O
consoles	O
that	O
are	O
logically	O
separate	O
,	O
but	O
which	O
access	O
the	O
same	O
physical	O
keyboard	B-Device
and	O
display	O
.	O
</s>
<s>
The	O
Linux	B-Application
console	I-Application
(	O
and	O
Linux	B-Application
virtual	I-Application
consoles	I-Application
)	O
are	O
implemented	O
by	O
the	O
VT	O
subsystem	O
of	O
the	O
Linux	B-Operating_System
kernel	I-Operating_System
,	O
and	O
do	O
not	O
rely	O
on	O
any	O
user	B-Operating_System
space	I-Operating_System
software	O
.	O
</s>
<s>
This	O
is	O
in	O
contrast	O
to	O
a	O
terminal	B-Application
emulator	I-Application
,	O
which	O
is	O
a	O
user	B-Operating_System
space	I-Operating_System
process	O
that	O
emulates	O
a	O
terminal	O
,	O
and	O
is	O
typically	O
used	O
in	O
a	O
graphical	O
display	O
environment	O
.	O
</s>
<s>
The	O
Linux	B-Application
console	I-Application
was	O
one	O
of	O
the	O
first	O
features	O
of	O
the	O
kernel	B-Operating_System
and	O
was	O
originally	O
written	O
by	O
Linus	O
Torvalds	O
in	O
1991	O
(	O
see	O
history	B-Operating_System
of	I-Operating_System
Linux	I-Operating_System
)	O
.	O
</s>
<s>
There	O
are	O
two	O
main	O
implementations	O
:	O
framebuffer	B-Language
and	O
text	B-Application
mode	I-Application
.	O
</s>
<s>
The	O
framebuffer	B-Language
implementation	O
is	O
the	O
default	O
in	O
modern	O
Linux	B-Application
distributions	I-Application
,	O
and	O
together	O
with	O
kernel	B-Operating_System
mode	O
setting	O
,	O
provides	O
kernel-level	O
support	O
for	O
display	O
hardware	O
and	O
features	O
such	O
as	O
showing	O
graphics	O
while	O
the	O
system	O
is	O
booting	O
.	O
</s>
<s>
The	O
legacy	O
text	B-Application
mode	I-Application
implementation	O
was	O
used	O
in	O
PC-compatible	O
systems	O
with	O
CGA	B-Device
,	O
EGA	B-Device
,	O
MDA	B-Device
and	O
VGA	B-Protocol
graphics	I-Protocol
cards	O
.	O
</s>
<s>
Non-x86	O
architectures	O
used	O
framebuffer	B-Language
mode	O
because	O
their	O
graphics	O
cards	O
did	O
not	O
implement	O
text	B-Application
mode	I-Application
.	O
</s>
<s>
The	O
Linux	B-Application
console	I-Application
uses	O
fixed-size	O
bitmap	O
,	O
monospace	O
fonts	O
,	O
usually	O
defaulting	O
to	O
8x16	O
pixels	O
per	O
character	O
.	O
</s>
<s>
The	O
Linux	B-Application
console	I-Application
is	O
an	O
optional	O
kernel	B-Operating_System
feature	O
,	O
and	O
most	O
embedded	B-Application
Linux	I-Application
systems	O
do	O
not	O
enable	O
it	O
.	O
</s>
<s>
web	O
based	O
)	O
,	O
or	O
boot	O
immediately	O
into	O
a	O
graphical	B-Application
user	I-Application
interface	I-Application
and	O
use	O
this	O
as	O
the	O
primary	O
means	O
of	O
interacting	O
with	O
the	O
user	O
.	O
</s>
<s>
Other	O
implementations	O
of	O
the	O
Linux	B-Application
console	I-Application
include	O
the	O
Braille	O
console	O
to	O
support	O
refreshable	O
Braille	O
displays	O
and	O
the	O
serial	B-Protocol
port	I-Protocol
console	O
.	O
</s>
<s>
The	O
Linux	B-Application
console	I-Application
provides	O
a	O
way	O
for	O
the	O
kernel	B-Operating_System
and	O
other	O
processes	O
to	O
output	O
text-based	O
messages	O
to	O
the	O
user	O
,	O
and	O
to	O
receive	O
text-based	O
input	O
from	O
the	O
user	O
.	O
</s>
<s>
In	O
Linux	B-Operating_System
,	O
several	O
devices	O
can	O
be	O
used	O
as	O
system	B-Device
console	I-Device
:	O
a	O
virtual	B-Application
terminal	I-Application
,	O
serial	B-Protocol
port	I-Protocol
,	O
USB	O
serial	B-Protocol
port	I-Protocol
,	O
VGA	B-Protocol
in	O
text-mode	B-Application
,	O
framebuffer	B-Language
.	O
</s>
<s>
Some	O
modern	O
Linux-based	O
systems	O
have	O
deprecated	O
kernel	B-Operating_System
based	O
text-mode	B-Application
input	O
and	O
output	O
,	O
and	O
instead	O
show	O
a	O
graphical	O
logo	O
or	O
progress	O
bar	O
while	O
the	O
system	O
is	O
booting	O
,	O
followed	O
by	O
the	O
immediate	O
start	O
of	O
a	O
graphical	B-Application
user	I-Application
interface	I-Application
(	O
e.g.	O
</s>
<s>
the	O
X.Org	B-Operating_System
Server	I-Operating_System
on	O
desktop	O
distributions	O
,	O
or	O
SurfaceFlinger	O
on	O
Android	O
)	O
.	O
</s>
<s>
During	O
kernel	B-Operating_System
boot	O
,	O
the	O
console	O
is	O
commonly	O
used	O
to	O
display	O
the	O
boot	O
log	O
of	O
the	O
kernel	B-Operating_System
.	O
</s>
<s>
At	O
this	O
point	O
in	O
time	O
,	O
the	O
kernel	B-Operating_System
is	O
the	O
only	O
software	O
running	O
,	O
and	O
hence	O
logging	O
via	O
user-space	B-Operating_System
(	O
e.g.	O
</s>
<s>
syslog	B-Protocol
)	O
is	O
not	O
possible	O
,	O
so	O
the	O
console	O
provides	O
a	O
convenient	O
place	O
to	O
output	O
this	O
information	O
.	O
</s>
<s>
Once	O
the	O
kernel	B-Operating_System
has	O
finished	O
booting	O
,	O
it	O
runs	O
the	O
init	B-Operating_System
process	O
(	O
also	O
sending	O
output	O
to	O
the	O
console	O
)	O
,	O
which	O
handles	O
booting	O
of	O
the	O
rest	O
of	O
the	O
system	O
including	O
starting	O
any	O
background	O
daemons	B-Operating_System
.	O
</s>
<s>
After	O
the	O
init	B-Operating_System
boot	O
process	O
is	O
complete	O
,	O
the	O
console	O
will	O
be	O
used	O
to	O
multiplex	B-Architecture
multiple	O
virtual	B-Application
terminals	I-Application
(	O
accessible	O
by	O
pressing	O
Ctrl-Alt-F1	O
,	O
Ctrl-Alt-F2	O
etc.	O
,	O
Ctrl-Alt-LeftArrow	O
,	O
Ctrl-Alt-RightArrow	O
,	O
or	O
using	O
chvt	O
)	O
.	O
</s>
<s>
On	O
each	O
virtual	B-Application
terminal	I-Application
,	O
a	O
getty	B-Device
process	I-Device
is	O
run	O
,	O
which	O
in	O
turn	O
runs	O
/bin/login	O
to	O
authenticate	O
a	O
user	O
.	O
</s>
<s>
Virtual	B-Application
terminals	I-Application
,	O
like	O
the	O
console	O
,	O
are	O
supported	O
at	O
the	O
Linux	B-Operating_System
kernel	I-Operating_System
level	O
.	O
</s>
<s>
The	O
Linux	B-Application
console	I-Application
implements	O
a	O
terminal	B-Application
type	I-Application
of	O
"	O
linux	B-Operating_System
"	O
and	O
the	O
escape	O
sequences	O
it	O
uses	O
are	O
in	O
the	O
console_codes	O
man	B-Protocol
page	I-Protocol
.	O
</s>
<s>
Virtual	B-Application
consoles	I-Application
allow	O
the	O
storage	O
of	O
multiple	O
text	O
buffers	O
,	O
enabling	O
different	O
console	O
programs	O
to	O
run	O
simultaneously	O
but	O
interact	O
with	O
the	O
user	O
in	O
different	O
contexts	O
.	O
</s>
<s>
Each	O
virtual	B-Application
console	I-Application
can	O
have	O
its	O
own	O
character	B-General_Concept
set	I-General_Concept
and	O
keyboard	B-Device
layout	O
.	O
</s>
<s>
Linux	B-Operating_System
2.6	I-Operating_System
introduced	O
the	O
ability	O
to	O
load	O
a	O
different	O
font	O
for	O
each	O
virtual	B-Application
console	I-Application
(	O
kernel	B-Operating_System
versions	O
predating	O
2.6	O
change	O
the	O
font	O
only	O
on	O
demand	O
)	O
.	O
</s>
<s>
The	O
text	B-Application
mode	I-Application
implementation	O
is	O
used	O
on	O
PC-based	O
systems	O
with	O
a	O
legacy	O
CGA/EGA/MDA/VGA	O
video	O
card	O
that	O
implements	O
text-based	O
video	O
modes	O
.	O
</s>
<s>
In	O
text	B-Application
mode	I-Application
,	O
the	O
kernel	B-Operating_System
sends	O
a	O
2D	O
array	O
of	O
characters	O
to	O
the	O
video	O
card	O
,	O
and	O
the	O
video	O
card	O
converts	O
the	O
characters	O
to	O
pixels	O
for	O
display	O
.	O
</s>
<s>
The	O
text	O
buffer	O
is	O
a	O
part	O
of	O
VGA	B-Protocol
memory	O
which	O
describes	O
the	O
content	O
of	O
a	O
text	O
screen	O
in	O
terms	O
of	O
code	O
points	O
and	O
character	O
attributes	O
.	O
</s>
<s>
Code	O
points	O
in	O
the	O
text	O
buffer	O
and	O
font	O
are	O
generally	O
not	O
the	O
same	O
as	O
encoding	B-General_Concept
used	O
in	O
text	O
terminal	O
semantics	O
to	O
put	O
characters	O
on	O
the	O
screen	O
.	O
</s>
<s>
The	O
set	O
of	O
glyphs	B-Application
on	O
the	O
screen	O
is	O
determined	O
by	O
the	O
current	O
font	O
.	O
</s>
<s>
The	O
Linux	B-Operating_System
kernel	I-Operating_System
(	O
driver	O
)	O
has	O
almost	O
complete	O
support	O
for	O
keyboard	B-Device
input	O
(	O
keyboard	B-Device
layouts	O
)	O
,	O
but	O
it	O
remains	O
a	O
bit	O
inconsistent	O
because	O
it	O
interacts	O
badly	O
with	O
different	O
character	B-General_Concept
sets	I-General_Concept
.	O
</s>
<s>
These	O
two	O
utilities	O
and	O
corresponding	O
data	O
files	O
are	O
packed	O
in	O
Linux	B-Application
Console	I-Application
Tools	I-Application
shipped	O
with	O
many	O
Linux	B-Application
distributions	I-Application
.	O
</s>
<s>
Efforts	O
on	O
the	O
internationalization	O
of	O
Linux	B-Operating_System
at	O
the	O
kernel	B-Operating_System
level	O
started	O
as	O
early	O
as	O
in	O
1994	O
by	O
Markus	O
Kuhn	O
and	O
Andries	O
Brouwer	O
.	O
</s>
<s>
The	O
Linux	B-Application
console	I-Application
is	O
capable	O
of	O
supporting	O
any	O
VGA-style	O
text	B-Application
mode	I-Application
,	O
but	O
the	O
kernel	B-Operating_System
itself	O
has	O
very	O
limited	O
means	O
to	O
set	O
these	O
modes	O
up	O
.	O
</s>
<s>
SVGATextMode	O
helps	O
to	O
enable	O
more	O
complex	O
text	B-Application
modes	I-Application
than	O
the	O
standard	O
EGA	B-Device
and	O
VGA	B-Protocol
modes	O
.	O
</s>
<s>
It	O
is	O
fully	O
compatible	O
with	O
Console	O
Tools	O
,	O
but	O
has	O
some	O
conflicts	O
with	O
dosemu	B-Application
,	O
SVGAlib	B-Application
and	O
display	O
servers	B-Application
.	O
</s>
<s>
Currently	O
,	O
there	O
is	O
no	O
support	O
for	O
different	O
modes	O
on	O
different	O
virtual	B-Application
consoles	I-Application
.	O
</s>
<s>
Microsoft	B-Application
Windows	I-Application
(	O
of	O
any	O
version	O
)	O
does	O
not	O
have	O
a	O
fully	O
functional	O
support	O
of	O
the	O
console	O
.	O
</s>
<s>
The	O
comparable	O
feature	O
there	O
,	O
but	O
for	O
application	O
software	O
only	O
,	O
is	O
the	O
Win32	B-Application
console	I-Application
.	O
</s>
<s>
Feature	O
Linux	B-Operating_System
Windows	O
DOS	B-Device
VGA	B-Protocol
text	O
attributes	O
Custom	O
fonts	O
Character	B-General_Concept
set	I-General_Concept
512	O
glyphs	B-Application
max	O
.	O
</s>
<s>
Unicode	O
supported	O
since	O
Windows	B-Device
NT	I-Device
based	O
systems	O
,	O
which	O
allow	O
to	O
switch	O
code	O
pages	O
and	O
use	O
Unicode	O
,	O
but	O
only	O
in	O
window	O
mode	O
.	O
</s>
<s>
Also	O
,	O
NT	O
systems	O
use	O
own	O
text	O
buffer	O
format	O
incompatible	O
with	O
VGA	B-Protocol
,	O
which	O
produces	O
an	O
overhead	O
in	O
hardware	B-Application
text	I-Application
modes	I-Application
.	O
</s>
<s>
As	O
non-ASCII	O
keyboard	B-Device
layout	O
should	O
be	O
reloaded	O
because	O
of	O
flawed	O
implementation	O
.	O
</s>
<s>
in	O
recent	O
kernels	B-Operating_System
make	O
this	O
more	O
practical	O
for	O
some	O
video	O
hardware	O
.	O
</s>
<s>
The	O
Linux	B-Language
framebuffer	I-Language
(	O
fbdev	B-Language
)	O
is	O
a	O
graphic	O
hardware-independent	O
abstraction	O
layer	O
,	O
which	O
was	O
originally	O
implemented	O
to	O
allow	O
the	O
Linux	B-Operating_System
kernel	I-Operating_System
to	O
emulate	O
a	O
text	O
console	O
on	O
systems	O
such	O
as	O
the	O
Apple	O
Macintosh	O
that	O
do	O
not	O
have	O
a	O
text-mode	B-Application
display	O
.	O
</s>
<s>
Now	O
it	O
offers	O
a	O
kernel	B-Operating_System
space	I-Operating_System
text	B-Application
mode	I-Application
emulation	O
on	O
any	O
platform	O
.	O
</s>
<s>
It	O
also	O
permits	O
to	O
overcome	O
all	O
technical	O
restrictions	O
of	O
VGA	B-Protocol
text	B-Application
modes	I-Application
.	O
</s>
<s>
A	O
Linux	B-Language
framebuffer	I-Language
console	O
differs	O
from	O
a	O
VGA	B-Protocol
one	O
only	O
in	O
ways	O
of	O
drawing	O
characters	O
.	O
</s>
<s>
The	O
processing	O
of	O
keyboard	B-Device
events	O
and	O
virtual	O
consoles’	O
support	O
are	O
exactly	O
the	O
same	O
.	O
</s>
<s>
Linux	B-Operating_System
serial	B-Device
console	I-Device
is	O
a	O
console	O
implementation	O
via	O
serial	B-Protocol
port	I-Protocol
,	O
enabled	O
by	O
option	O
CONFIG_SERIAL_CONSOLE	O
in	O
the	O
kernel	B-Operating_System
configuration	O
.	O
</s>
<s>
It	O
may	O
be	O
used	O
in	O
some	O
embedded	B-Architecture
systems	I-Architecture
,	O
and	O
on	O
servers	B-Application
,	O
where	O
a	O
direct	O
interaction	O
with	O
operator	O
is	O
not	O
expected	O
.	O
</s>
<s>
The	O
serial	B-Device
console	I-Device
allows	O
the	O
same	O
mode	O
of	O
access	O
for	O
the	O
system	O
,	O
but	O
usually	O
at	O
a	O
slower	O
speed	O
due	O
to	O
the	O
small	O
bandwidth	O
of	O
RS-232	O
.	O
</s>
<s>
A	O
serial	B-Device
console	I-Device
is	O
often	O
used	O
during	O
development	O
of	O
software	O
for	O
embedded	B-Architecture
systems	I-Architecture
,	O
and	O
is	O
sometimes	O
left	O
accessible	O
via	O
a	O
debug	O
port	O
.	O
</s>
<s>
Aside	O
from	O
the	O
textual	O
blanking	O
,	O
there	O
is	O
no	O
known	O
way	O
to	O
place	O
the	O
VGA	B-Protocol
adapter	I-Protocol
into	O
standby	O
.	O
</s>
<s>
The	O
Kmscon	B-Application
projects	O
aims	O
to	O
create	O
a	O
modern	O
user-space	B-Operating_System
replacement	O
for	O
the	O
Linux	B-Application
console	I-Application
.	O
</s>
<s>
Development	O
priorities	O
include	O
support	O
for	O
multi-monitor	B-General_Concept
setups	O
,	O
Unicode	O
font	O
rendering	O
with	O
Pango	B-Language
,	O
XKB	B-Application
keyboard	B-Device
handling	O
,	O
and	O
GPU	B-Architecture
OpenGL	B-Application
acceleration	O
.	O
</s>
<s>
Complaints	O
about	O
the	O
current	O
kernel	B-Operating_System
implementation	O
include	O
"	O
that	O
it	O
's	O
a	O
user-interface	O
in	O
kernel-space	B-Operating_System
,	O
the	O
code	O
is	O
poorly	O
maintained	O
,	O
handles	O
keyboards	B-Device
badly	O
,	O
produces	O
bad	O
font	O
rendering	O
,	O
misses	O
out	O
on	O
mode-setting	O
and	O
multi-head	O
support	O
,	O
contains	O
no	O
multi-seat	O
awareness	O
,	O
and	O
only	O
has	O
limited	O
hot-plugging	O
handling	O
,	O
limited	O
to	O
VT102	O
compliance.	O
"	O
</s>
<s>
Name	O
Major	O
Minor	O
Description	O
/dev/tty0	O
c	O
4	O
0	O
"	O
current	O
console	O
"	O
tty1	O
...	O
c	O
4	O
1	O
...	O
63	O
virtual	O
consoles(keyboard controlled )	O
ttyS0	O
...	O
c	O
4	O
64	O
...	O
</s>
<s>
Serial	B-Protocol
ports	I-Protocol
,	O
suitable	O
for	O
system	B-Device
console	I-Device
/dev/vcs	O
c	O
7	O
0	O
Virtual	B-Application
Console	I-Application
Screen/dev/vcs	O
is	O
the	O
contents	O
of	O
the	O
current	O
virtual	O
screen	O
.	O
</s>
<s>
vcs1	O
...	O
c	O
7	O
1	O
...	O
63	O
The	O
text	O
(	O
the	O
character	B-Application
pointer	I-Application
table	I-Application
)	O
of	O
a	O
virtual	O
screen	O
.	O
</s>
