<s>
The	O
Color	B-Device
Graphics	I-Device
Adapter	I-Device
(	O
CGA	B-Device
)	O
,	O
originally	O
also	O
called	O
the	O
Color/Graphics	B-Device
Adapter	I-Device
or	O
IBM	O
Color/Graphics	O
Monitor	B-Device
Adapter	O
,	O
introduced	O
in	O
1981	O
,	O
was	O
IBM	O
's	O
first	O
color	O
graphics	B-Device
card	I-Device
for	O
the	O
IBM	B-Device
PC	I-Device
and	O
established	O
a	O
de	O
facto	O
computer	B-Device
display	I-Device
standard	O
.	O
</s>
<s>
The	O
original	O
IBM	B-Device
CGA	I-Device
graphics	B-Device
card	I-Device
was	O
built	O
around	O
the	O
Motorola	B-General_Concept
6845	I-General_Concept
display	O
controller	O
,	O
came	O
with	O
16kilobytes	O
of	O
video	O
memory	O
built	O
in	O
,	O
and	O
featured	O
several	O
graphics	O
and	O
text	B-Application
modes	I-Application
.	O
</s>
<s>
The	O
highest	O
display	B-General_Concept
resolution	I-General_Concept
of	O
any	O
mode	O
was	O
640×200	O
,	O
and	O
the	O
highest	O
color	O
depth	O
supported	O
was	O
4-bit	O
(	O
16colors	O
)	O
.	O
</s>
<s>
The	O
CGA	B-Device
card	O
could	O
be	O
connected	O
either	O
to	O
a	O
direct-drive	O
CRT	B-Device
monitor	I-Device
using	O
a	O
4-bit	O
digital	O
(	O
TTL	B-General_Concept
)	O
RGBI	O
interface	O
,	O
such	O
as	O
the	O
IBM	O
5153	O
color	O
display	O
,	O
or	O
to	O
an	O
NTSC-compatible	O
television	O
or	O
composite	O
video	O
monitor	B-Device
via	O
an	O
RCA	B-Protocol
connector	I-Protocol
.	O
</s>
<s>
The	O
RCA	B-Protocol
connector	I-Protocol
provided	O
only	O
baseband	O
video	O
,	O
so	O
to	O
connect	O
the	O
CGA	B-Device
card	O
to	O
a	O
television	O
set	O
without	O
a	O
composite	O
video	O
input	O
required	O
a	O
separate	O
RF	O
modulator	O
.	O
</s>
<s>
IBM	O
produced	O
the	O
5153	O
Personal	O
Computer	O
Color	O
Display	O
for	O
use	O
with	O
the	O
CGA	B-Device
,	O
but	O
this	O
was	O
not	O
available	O
at	O
release	O
and	O
would	O
not	O
be	O
released	O
until	O
March	O
1983	O
.	O
</s>
<s>
CGA	B-Device
offered	O
several	O
video	O
modes	O
.	O
</s>
<s>
160×100	O
in	O
16	O
colors	O
,	O
chosen	O
from	O
a	O
16-color	O
palette	O
,	O
utilizing	O
a	O
specific	O
configuration	O
of	O
the	O
80x25	B-Application
text	B-Application
mode	I-Application
.	O
</s>
<s>
Some	O
software	O
achieved	O
greater	O
color	O
depth	O
by	O
utilizing	O
artifact	O
color	O
when	O
connected	O
to	O
a	O
composite	O
monitor	B-Device
.	O
</s>
<s>
Text	B-Application
modes	I-Application
:	O
</s>
<s>
IBM	O
intended	O
that	O
CGA	B-Device
be	O
compatible	O
with	O
a	O
home	O
television	O
set	O
.	O
</s>
<s>
The	O
40×25	O
text	O
and	O
320×200	O
graphics	O
modes	O
are	O
usable	O
with	O
a	O
television	O
,	O
and	O
the	O
80×25	O
text	O
and	O
640×200	O
graphics	O
modes	O
are	O
intended	O
for	O
a	O
monitor	B-Device
.	O
</s>
<s>
CGA	B-Device
uses	O
a	O
4-bit	O
RGBI	O
16-color	O
gamut	O
,	O
but	O
not	O
all	O
colors	O
are	O
available	O
at	O
all	O
times	O
,	O
depending	O
on	O
which	O
graphics	O
mode	O
is	O
being	O
used	O
.	O
</s>
<s>
These	O
four	O
colour	O
bits	O
are	O
then	O
interpreted	O
internally	O
by	O
the	O
monitor	B-Device
,	O
or	O
converted	O
to	O
NTSC	O
colours	O
(	O
see	O
below	O
)	O
.	O
</s>
<s>
When	O
using	O
a	O
direct-drive	O
monitor	B-Device
,	O
the	O
four	O
color	O
bits	O
are	O
output	O
directly	O
to	O
the	O
DE-9	B-Protocol
connector	I-Protocol
at	O
the	O
back	O
of	O
the	O
card	O
.	O
</s>
<s>
Within	O
the	O
monitor	B-Device
,	O
the	O
four	O
signals	O
are	O
interpreted	O
to	O
drive	O
the	O
red	O
,	O
green	O
and	O
blue	O
color	O
guns	O
.	O
</s>
<s>
With	O
respect	O
to	O
the	O
RGBI	O
color	O
model	O
described	O
above	O
,	O
the	O
monitor	B-Device
would	O
use	O
approximately	O
the	O
following	O
formula	O
to	O
process	O
the	O
digital	O
four-bit	O
color	O
number	O
to	O
analog	O
voltages	O
ranging	O
from	O
0.0	O
to	O
1.0	O
:	O
</s>
<s>
The	O
exact	O
amount	O
of	O
reduction	O
differed	O
between	O
monitor	B-Device
models	O
:	O
the	O
original	O
IBM	O
5153	O
Personal	O
Computer	O
Color	O
Display	O
reduces	O
the	O
green	O
signal	O
's	O
amplitude	O
by	O
about	O
one	O
third	O
,	O
while	O
the	O
IBM	O
5154	O
Enhanced	O
Color	O
Display	O
internally	O
converts	O
all	O
4-bit	O
RGBI	O
color	O
numbers	O
to	O
6-bit	O
ECD	O
color	O
numbers	O
,	O
which	O
amounts	O
to	O
halving	O
the	O
green	O
signal	O
's	O
amplitude	O
.	O
</s>
<s>
This	O
"	O
RGBI	O
with	O
tweaked	O
brown	O
"	O
palette	O
was	O
retained	O
as	O
the	O
default	O
palette	O
of	O
later	O
PC	O
graphics	O
standards	O
such	O
as	O
EGA	B-Device
and	O
VGA	B-Protocol
,	O
which	O
can	O
select	O
colors	O
from	O
much	O
larger	O
gamuts	O
,	O
but	O
default	O
to	O
these	O
until	O
reprogrammed	O
.	O
</s>
<s>
For	O
the	O
composite	O
output	O
,	O
these	O
four-bit	O
color	O
numbers	O
are	O
encoded	O
by	O
the	O
CGA	B-Device
's	O
onboard	O
hardware	O
into	O
an	O
NTSC-compatible	O
signal	O
fed	O
to	O
the	O
card	O
's	O
RCA	O
output	O
jack	O
.	O
</s>
<s>
The	O
relative	O
luminances	O
of	O
the	O
colors	O
produced	O
by	O
the	O
composite	O
color-generating	O
circuit	O
differ	O
between	O
CGA	B-Device
revisions	O
:	O
they	O
are	O
identical	O
for	O
colors	O
1-6	O
and	O
9-14	O
with	O
early	O
CGAs	B-Device
produced	O
until	O
1983	O
,	O
and	O
are	O
different	O
for	O
later	O
CGAs	B-Device
due	O
to	O
the	O
addition	O
of	O
additional	O
resistors	O
.	O
</s>
<s>
CGA	B-Device
offers	O
four	O
BIOS	O
text	B-Application
modes	I-Application
(	O
Modes	O
0	O
to	O
3	O
,	O
called	O
alphanumeric	O
or	O
A/N	O
modes	O
in	O
IBM	O
's	O
documentation	O
)	O
.	O
</s>
<s>
Instead	O
,	O
the	O
screen	O
is	O
divided	O
into	O
a	O
grid	O
of	O
character	B-Application
cells	I-Application
,	O
each	O
displaying	O
a	O
character	O
defined	O
in	O
one	O
of	O
two	O
bitmap	O
fonts	O
,	O
"	O
normal	O
"	O
and	O
"	O
thin	O
,	O
"	O
included	O
in	O
the	O
card	O
's	O
ROM	O
.	O
</s>
<s>
These	O
colors	O
can	O
be	O
chosen	O
independently	O
,	O
for	O
each	O
character	O
on	O
the	O
screen	O
,	O
from	O
the	O
full	O
16-color	O
CGA	B-Device
palette	O
.	O
</s>
<s>
BIOS	O
Modes	O
0	O
and	O
1	O
are	O
both	O
40	O
columns	O
by	O
25	O
rows	O
text	B-Application
modes	I-Application
,	O
with	O
each	O
character	O
a	O
pattern	O
of	O
8×8	O
dots	O
.	O
</s>
<s>
The	O
effective	O
screen	B-General_Concept
resolution	I-General_Concept
in	O
this	O
mode	O
is	O
320×200	O
pixels	O
(	O
a	O
pixel	B-Device
aspect	I-Device
ratio	I-Device
of	O
1:1.2	O
.	O
)	O
</s>
<s>
The	O
difference	O
between	O
these	O
two	O
modes	O
can	O
only	O
be	O
seen	O
on	O
a	O
composite	O
monitor	B-Device
,	O
where	O
mode	O
0	O
disables	O
the	O
color	O
burst	O
,	O
making	O
all	O
text	O
appear	O
in	O
grayscale	O
.	O
</s>
<s>
Mode	O
0	O
and	O
Mode	O
1	O
are	O
functionally	O
identical	O
on	O
RGB	B-Device
monitors	I-Device
and	O
on	O
later	O
adapters	O
that	O
emulate	O
CGA	B-Device
without	O
supporting	O
composite	O
color	O
output	O
.	O
</s>
<s>
BIOS	O
Modes	O
2	O
and	O
3	O
select	O
80	O
columns	O
by	O
25	O
rows	O
text	B-Application
modes	I-Application
,	O
with	O
each	O
character	O
still	O
an	O
8×8	O
dot	O
pattern	O
,	O
but	O
displayed	O
at	O
a	O
higher	O
scan	O
rate	O
.	O
</s>
<s>
The	O
effective	O
screen	B-General_Concept
resolution	I-General_Concept
of	O
this	O
mode	O
is	O
640×200	O
pixels	O
.	O
</s>
<s>
As	O
with	O
the	O
40-column	O
text	B-Application
modes	I-Application
,	O
Mode	O
2	O
disables	O
the	O
color	O
burst	O
in	O
the	O
composite	O
signal	O
and	O
Mode	O
3	O
enables	O
it	O
.	O
</s>
<s>
Each	O
character	B-Application
cell	I-Application
stored	O
four	O
bits	O
for	O
foreground	O
and	O
background	O
color	O
.	O
</s>
<s>
Notably	O
,	O
the	O
GW-BASIC	B-Language
and	O
Microsoft	B-Language
QBASIC	I-Language
programming	O
languages	O
included	O
with	O
MS-DOS	B-Application
supported	O
all	O
the	O
text	B-Application
modes	I-Application
of	O
the	O
CGA	B-Device
with	O
full	O
color	O
control	O
,	O
but	O
did	O
not	O
provide	O
a	O
normal	O
means	O
through	O
the	O
BASIC	O
language	O
to	O
switch	O
the	O
CGA	B-Device
from	O
blink	O
mode	O
to	O
16-background-color	O
mode	O
.	O
</s>
<s>
CGA	B-Device
offers	O
graphics	O
modes	O
at	O
three	O
resolutions	O
:	O
160×100	O
,	O
320×200	O
and	O
640×200	O
.	O
</s>
<s>
The	O
low-resolution	O
160×100	O
mode	O
is	O
in	O
fact	O
80×25	O
character	B-Application
mode	I-Application
(	O
Mode	O
3	O
)	O
.	O
</s>
<s>
Because	O
the	O
built-in	O
character	O
ROM	O
contains	O
semigraphics	B-Data_Structure
elements	O
,	O
such	O
as	O
a	O
character	O
that	O
has	O
a	O
foreground-colored	O
upper	O
half	O
and	O
a	O
background-colored	O
lower	O
half	O
( ▄	O
)	O
,	O
and	O
because	O
foreground	O
and	O
background	O
colors	O
can	O
be	O
chosen	O
freely	O
in	O
textmode	B-Application
,	O
a	O
low-resolution	O
but	O
full-color	O
graphical	O
display	O
can	O
be	O
achieved	O
.	O
</s>
<s>
As	O
with	O
the	O
text	B-Application
modes	I-Application
0	O
and	O
2	O
,	O
Mode	O
5	O
disables	O
the	O
color	O
burst	O
to	O
allow	O
colors	O
to	O
appear	O
in	O
grayscale	O
on	O
composite	O
monitor	B-Device
.	O
</s>
<s>
However	O
,	O
unlike	O
the	O
text	B-Application
modes	I-Application
,	O
this	O
also	O
affects	O
the	O
colors	O
displayed	O
on	O
an	O
RGBI	O
monitor	B-Device
,	O
altering	O
them	O
to	O
the	O
cyan/red/white	O
palette	O
seen	O
above	O
.	O
</s>
<s>
By	O
default	O
the	O
colors	O
are	O
black	O
and	O
bright	O
white	O
,	O
but	O
the	O
foreground	O
color	O
can	O
be	O
changed	O
to	O
any	O
entry	O
in	O
the	O
16-color	O
CGA	B-Device
palette	O
.	O
</s>
<s>
The	O
background	O
color	O
cannot	O
be	O
changed	O
from	O
black	O
on	O
an	O
original	O
IBM	B-Device
CGA	I-Device
card	O
.	O
</s>
<s>
In	O
320×200	O
graphics	O
mode	O
,	O
the	O
background	O
color	O
(	O
which	O
also	O
affects	O
the	O
border	O
color	O
)	O
,	O
which	O
defaults	O
to	O
black	O
on	O
mode	O
initialization	O
,	O
can	O
be	O
changed	O
to	O
any	O
of	O
the	O
other	O
15	O
colors	O
of	O
the	O
CGA	B-Device
palette	O
.	O
</s>
<s>
In	O
text	B-Application
mode	I-Application
,	O
the	O
border	O
color	O
(	O
displayed	O
outside	O
the	O
regular	O
display	O
area	O
and	O
including	O
the	O
overscan	O
area	O
)	O
can	O
be	O
changed	O
from	O
the	O
default	O
black	O
to	O
any	O
of	O
the	O
other	O
15colors	O
.	O
</s>
<s>
An	O
example	O
of	O
this	O
is	O
California	B-Device
Games	I-Device
,	O
when	O
run	O
on	O
a	O
stock	O
4.77MHz	O
8088	O
.	O
</s>
<s>
The	O
same	O
can	O
be	O
done	O
with	O
the	O
background	O
color	O
,	O
as	O
is	O
used	O
to	O
create	O
the	O
river	O
and	O
road	O
in	O
Frogger	B-Application
.	O
</s>
<s>
Another	O
documented	O
example	O
of	O
the	O
technique	O
is	O
in	O
Atarisoft	O
's	O
port	O
of	O
Jungle	B-Application
Hunt	I-Application
to	O
the	O
PC	O
.	O
</s>
<s>
Technically	O
,	O
this	O
mode	O
is	O
not	O
a	O
graphics	O
mode	O
,	O
but	O
a	O
tweak	O
of	O
the	O
80×25	O
text	B-Application
mode	I-Application
.	O
</s>
<s>
The	O
character	B-Application
cell	I-Application
height	O
register	O
is	O
changed	O
to	O
display	O
only	O
two	O
lines	O
per	O
character	B-Application
cell	I-Application
instead	O
of	O
the	O
normal	O
eight	O
lines	O
.	O
</s>
<s>
Character	O
221	O
of	O
the	O
CGA	B-Device
character	O
set	O
consists	O
of	O
a	O
box	O
occupying	O
the	O
entire	O
left	O
half	O
of	O
the	O
character	O
matrix	O
.	O
</s>
<s>
Using	O
either	O
character	O
221	O
or	O
222	O
,	O
each	O
half	O
of	O
each	O
truncated	O
character	B-Application
cell	I-Application
can	O
thus	O
be	O
treated	O
as	O
an	O
individual	O
pixel	O
—	O
making	O
160	O
horizontal	O
pixels	O
available	O
per	O
line	O
.	O
</s>
<s>
Thus	O
,	O
160×100	O
pixels	O
at	O
16colors	O
,	O
with	O
an	O
aspect	B-Device
ratio	I-Device
of	O
1:1.2	O
,	O
are	O
possible	O
.	O
</s>
<s>
This	O
was	O
explored	O
by	O
Macrocom	O
,	O
Inc	O
on	O
two	O
games	O
:	O
Icon	O
:	O
Quest	O
for	O
the	O
Ring	O
(	O
released	O
in	O
1984	O
)	O
and	O
The	B-Application
Seven	I-Application
Spirits	I-Application
of	I-Application
Ra	I-Application
(	O
released	O
in	O
1987	O
)	O
.	O
</s>
<s>
The	O
same	O
text	O
cell	O
height	O
reduction	O
technique	O
can	O
also	O
be	O
used	O
with	O
the	O
40×25	O
text	B-Application
mode	I-Application
,	O
yielding	O
a	O
resolution	O
of	O
80×100	O
.	O
</s>
<s>
Using	O
the	O
composite	O
output	O
instead	O
of	O
an	O
RGBI	O
monitor	B-Device
produced	O
lower-quality	O
video	O
,	O
due	O
to	O
NTSC	O
's	O
inferior	O
separation	O
between	O
luminance	O
and	O
chrominance	O
.	O
</s>
<s>
Direct	O
colors	O
are	O
the	O
normal	O
16	O
colors	O
as	O
described	O
above	O
under	O
"	O
The	O
CGA	B-Device
color	O
palette	O
"	O
.	O
</s>
<s>
Artifact	O
colors	O
are	O
seen	O
because	O
the	O
composite	O
monitor	B-Device
's	O
NTSC	O
chroma	O
decoder	O
misinterprets	O
some	O
of	O
the	O
luminance	O
information	O
as	O
color	O
.	O
</s>
<s>
Later	O
demonstrations	O
by	O
enthusiasts	O
have	O
increased	O
the	O
maximum	O
number	O
of	O
colors	O
the	O
CGA	B-Device
can	O
display	O
at	O
the	O
same	O
time	O
to	O
1024	O
.	O
</s>
<s>
This	O
technique	O
involves	O
a	O
text	B-Application
mode	I-Application
tweak	O
which	O
quadruples	O
the	O
number	O
of	O
text	O
rows	O
.	O
</s>
<s>
Certain	O
ASCII	O
characters	O
such	O
as	O
U	O
and	O
‼	O
are	O
then	O
used	O
to	O
produce	O
the	O
necessary	O
patterns	O
,	O
which	O
result	O
in	O
non-dithered	O
images	O
with	O
an	O
effective	O
resolution	O
of	O
80×100	O
on	O
a	O
composite	O
monitor	B-Device
.	O
</s>
<s>
The	O
320×200	O
variant	O
of	O
this	O
technique	O
(	O
see	O
above	O
)	O
is	O
how	O
the	O
standard	O
BIOS-supported	O
graphics	O
mode	O
looks	O
on	O
a	O
composite	O
color	B-Device
monitor	I-Device
.	O
</s>
<s>
The	O
640×200	O
variant	O
,	O
however	O
,	O
requires	O
modifying	O
a	O
bit	O
(	O
color	O
burst	O
disable	O
)	O
directly	O
in	O
the	O
CGA	B-Device
's	O
hardware	O
registers	O
.	O
</s>
<s>
Being	O
completely	O
dependent	O
on	O
the	O
NTSC	O
encoding/decoding	O
process	O
,	O
composite	O
color	O
artifacting	O
is	O
not	O
available	O
on	O
an	O
RGBI	O
monitor	B-Device
,	O
nor	O
is	O
it	O
emulated	O
by	O
EGA	B-Device
,	O
VGA	B-Protocol
or	O
contemporary	O
graphics	B-Device
adapters	I-Device
.	O
</s>
<s>
The	O
modern	O
,	O
games-centric	O
PC	O
emulator	O
DOSBox	B-Application
supports	O
a	O
CGA	B-Device
mode	O
,	O
which	O
can	O
emulate	O
a	O
composite	O
monitor	B-Device
's	O
color	O
artifacting	O
.	O
</s>
<s>
Many	O
high-profile	O
titles	O
offered	O
graphics	O
optimized	O
for	O
composite	O
color	B-Device
monitors	I-Device
.	O
</s>
<s>
Ultima	B-Application
II	I-Application
,	O
the	O
first	O
game	O
in	O
the	O
game	O
series	O
to	O
be	O
ported	O
to	O
IBM	B-Device
PC	I-Device
,	O
used	O
CGA	B-Device
composite	O
graphics	O
.	O
</s>
<s>
King	B-Device
's	I-Device
Quest	I-Device
I	I-Device
also	O
offered	O
16-color	O
graphics	O
on	O
the	O
PC	O
,	O
PCjr	B-Device
and	O
Tandy	O
1000	O
,	O
but	O
provided	O
a	O
'	O
RGB	O
mode	O
 '	O
at	O
the	O
title	O
screen	O
which	O
would	O
utilize	O
only	O
the	O
ordinary	O
CGA	B-Device
graphics	I-Device
mode	O
,	O
limited	O
to	O
4	O
colors	O
.	O
</s>
<s>
Video	O
timing	O
on	O
the	O
CGA	B-Device
is	O
provided	O
by	O
the	O
Motorola	B-General_Concept
6845	I-General_Concept
video	B-Device
controller	I-Device
.	O
</s>
<s>
To	O
realize	O
graphics	O
modes	O
with	O
200	O
scanlines	O
on	O
the	O
CGA	B-Device
,	O
the	O
MC6845	B-General_Concept
is	O
programmed	O
with	O
100	O
character	O
rows	O
per	O
picture	O
and	O
two	O
scanlines	O
per	O
character	O
row	O
.	O
</s>
<s>
Because	O
the	O
video	O
memory	O
address	O
output	O
by	O
the	O
MC6845	B-General_Concept
is	O
identical	O
for	O
each	O
scanline	O
within	O
a	O
character	O
row	O
,	O
the	O
CGA	B-Device
must	O
use	O
the	O
MC6845	B-General_Concept
's	O
"	O
row	O
address	O
"	O
output	O
(	O
i.e.	O
</s>
<s>
Instead	O
,	O
graphics	O
modes	O
on	O
the	O
CGA	B-Device
store	O
the	O
even-numbered	O
scanlines	O
contiguously	O
in	O
memory	O
,	O
followed	O
by	O
a	O
second	O
block	O
of	O
odd-numbered	O
scanlines	O
starting	O
at	O
video	O
memory	O
position	O
8,192	O
.	O
</s>
<s>
Even	O
though	O
the	O
MC6845	B-General_Concept
video	B-Device
controller	I-Device
can	O
provide	O
the	O
timing	O
for	O
interlaced	O
video	O
,	O
the	O
CGA	B-Device
's	O
circuitry	O
aligns	O
the	O
synchronization	O
signals	O
in	O
such	O
a	O
way	O
that	O
scanning	O
is	O
always	O
progressive	O
.	O
</s>
<s>
Consequently	O
,	O
it	O
is	O
impossible	O
to	O
double	O
the	O
vertical	O
resolution	O
to	O
400	O
scanlines	O
using	O
a	O
standard	O
15kHz	O
monitor	B-Device
.	O
</s>
<s>
The	O
higher	O
bandwidth	O
used	O
by	O
80-column	O
text	B-Application
mode	I-Application
results	O
in	O
random	O
short	O
horizontal	O
lines	O
appearing	O
onscreen	O
(	O
known	O
as	O
"	O
snow	O
"	O
)	O
if	O
a	O
program	O
writes	O
directly	O
to	O
video	O
memory	O
during	O
screen	O
drawing	O
.	O
</s>
<s>
The	O
"	O
snow	O
"	O
problem	O
does	O
not	O
occur	O
on	O
any	O
other	O
video	B-Device
adapter	I-Device
,	O
or	O
on	O
most	O
CGA	B-Device
clones	O
.	O
</s>
<s>
In	O
the	O
80-column	O
text	B-Application
mode	I-Application
,	O
the	O
pixel	O
clock	O
frequency	O
is	O
doubled	O
,	O
and	O
all	O
synchronization	O
signals	O
are	O
output	O
for	O
twice	O
the	O
number	O
of	O
clock	O
cycles	O
in	O
order	O
to	O
last	O
for	O
their	O
proper	O
duration	O
.	O
</s>
<s>
Hence	O
,	O
IBM	O
documentation	O
lists	O
the	O
80-column	O
text	B-Application
mode	I-Application
as	O
a	O
"	O
feature	O
"	O
only	O
for	O
RGBI	O
and	O
black-and-white	O
composite	O
monitors	O
.	O
</s>
<s>
The	O
CGA	B-Device
was	O
released	O
alongside	O
the	O
IBM	B-Device
MDA	I-Device
,	O
and	O
in	O
fact	O
could	O
be	O
installed	O
alongside	O
the	O
MDA	B-Device
in	O
the	O
same	O
computer	O
.	O
</s>
<s>
A	O
command	O
included	O
with	O
PC	O
DOS	O
permitted	O
switching	O
the	O
display	O
output	O
between	O
the	O
CGA	B-Device
and	O
MDA	B-Device
cards	I-Device
.	O
</s>
<s>
Some	O
programs	O
like	O
the	O
early	O
MS-DOS	B-Application
versions	O
of	O
AutoCAD	B-Algorithm
supported	O
using	O
both	O
displays	O
concurrently	O
.	O
</s>
<s>
CGA	B-Device
was	O
widely	O
supported	O
in	O
PC	O
software	O
up	O
until	O
the	O
1990s	O
.	O
</s>
<s>
BYTE	O
in	O
January	O
1982	O
described	O
the	O
output	O
from	O
CGA	B-Device
as	O
"	O
very	O
good	O
—	O
slightly	O
better	O
than	O
color	O
graphics	O
on	O
existing	O
microcomputers	O
"	O
.	O
</s>
<s>
Text	O
quality	O
on	O
displays	O
connected	O
to	O
the	O
color/graphics	B-Device
adapter	I-Device
...	O
is	O
at	O
best	O
of	O
medium	O
quality	O
and	O
is	O
conducive	O
to	O
eyestrain	O
over	O
the	O
long	O
haul	O
"	O
.	O
</s>
<s>
In	O
a	O
retrospective	O
commentary	O
,	O
Next	O
Generation	O
also	O
took	O
a	O
negative	O
view	O
on	O
the	O
CGA	B-Device
,	O
stating	O
,	O
"	O
Even	O
for	O
the	O
time	O
(	O
early	O
1980s	O
)	O
,	O
these	O
graphics	O
were	O
terrible	O
,	O
paling	O
in	O
comparison	O
to	O
other	O
color	O
machines	O
available	O
on	O
the	O
market.	O
"	O
</s>
<s>
CGA	B-Device
had	O
several	O
competitors	O
:	O
</s>
<s>
For	O
business	O
and	O
word	O
processing	O
use	O
,	O
IBM	O
provided	O
the	O
Monochrome	B-Device
Display	I-Device
Adapter	I-Device
(	O
MDA	B-Device
)	O
at	O
the	O
same	O
time	O
as	O
CGA	B-Device
.	O
</s>
<s>
MDA	B-Device
was	O
much	O
more	O
popular	O
than	O
CGA	B-Device
at	O
first	O
.	O
</s>
<s>
In	O
1982	O
,	O
the	O
non-IBM	O
Hercules	B-Device
Graphics	I-Device
Card	I-Device
(	O
HGC	O
)	O
was	O
introduced	O
,	O
the	O
first	O
third-party	O
video	B-Device
card	I-Device
for	O
the	O
PC	O
.	O
</s>
<s>
In	O
addition	O
to	O
an	O
MDA-compatible	O
text	B-Application
mode	I-Application
,	O
it	O
offered	O
a	O
monochrome	O
graphics	O
mode	O
with	O
a	O
resolution	O
of	O
720×348	O
pixels	O
,	O
higher	O
than	O
the	O
CGA	B-Device
.	O
</s>
<s>
Also	O
in	O
1982	O
the	O
Plantronics	O
Colorplus	O
board	O
was	O
introduced	O
,	O
with	O
twice	O
the	O
memory	O
of	O
a	O
standard	O
CGA	B-Device
board	O
(	O
32k	O
,	O
compared	O
to	O
16k	O
)	O
.	O
</s>
<s>
The	O
IBM	B-Device
PCjr	I-Device
(	O
1984	O
)	O
and	O
compatible	O
Tandy	O
1000	O
(	O
1985	O
)	O
featured	O
onboard	O
"	O
extended	O
CGA	B-Device
"	O
video	O
hardware	O
that	O
extended	O
video	O
RAM	O
beyond	O
16kB	O
,	O
allowing	O
16colors	O
at	O
320×200	O
resolution	O
and	O
four	O
colors	O
at	O
640×200	O
resolution	O
.	O
</s>
<s>
Because	O
the	O
Tandy	O
1000	O
long	O
outlived	O
the	O
PCjr	B-Device
,	O
the	O
video	O
modes	O
became	O
known	O
as	O
"	O
Tandy	O
Graphics	B-Device
Adapter	I-Device
"	O
or	O
"	O
TGA	O
"	O
,	O
and	O
were	O
very	O
popular	O
for	O
games	O
during	O
the	O
1980s	O
.	O
</s>
<s>
In	O
1984	O
,	O
IBM	O
also	O
introduced	O
the	O
Professional	B-Device
Graphics	I-Device
Controller	I-Device
,	O
a	O
high-end	O
graphics	O
solution	O
intended	O
for	O
e.g.	O
</s>
<s>
CAD	B-Application
applications	O
.	O
</s>
<s>
It	O
was	O
mostly	O
backwards	O
compatible	O
with	O
CGA	B-Device
.	O
</s>
<s>
Paradise	O
Systems	O
introduced	O
in	O
1984	O
the	O
first	O
successful	O
CGA-compatible	O
card	O
for	O
MDA	B-Device
monitors	O
.	O
</s>
<s>
It	O
displayed	O
CGA	B-Device
's	O
16	O
colors	O
in	O
shades	O
of	O
monochrome	O
.	O
</s>
<s>
Because	O
it	O
was	O
hardware-compatible	O
with	O
CGA	B-Device
,	O
the	O
Paradise	O
card	O
did	O
not	O
need	O
special	O
software	O
support	O
or	O
additional	O
drivers	O
.	O
</s>
<s>
Another	O
extension	O
in	O
some	O
CGA-compatible	O
chipsets	O
(	O
including	O
those	O
in	O
the	O
Olivetti	B-Operating_System
M24	I-Operating_System
/	O
AT&T	B-Operating_System
6300	I-Operating_System
,	O
the	O
DEC	O
VAXmate	B-Device
,	O
and	O
some	O
Compaq	O
and	O
Toshiba	O
portables	O
)	O
is	O
a	O
doubled	O
vertical	O
resolution	O
.	O
</s>
<s>
The	O
CGA	B-Device
card	O
was	O
succeeded	O
in	O
the	O
consumer	O
space	O
by	O
IBM	O
's	O
Enhanced	B-Device
Graphics	I-Device
Adapter	I-Device
(	O
EGA	B-Device
)	O
card	O
,	O
which	O
supports	O
most	O
of	O
CGA	B-Device
's	O
modes	O
and	O
adds	O
an	O
additional	O
resolution	O
(	O
640×350	O
)	O
as	O
well	O
as	O
a	O
software-selectable	O
palette	O
of	O
16colors	O
out	O
of	O
64	O
in	O
both	O
text	O
and	O
graphics	O
modes	O
.	O
</s>
<s>
The	O
Color	B-Device
Graphics	I-Device
Adapter	I-Device
uses	O
a	O
standard	O
DE-9	B-Protocol
connector	I-Protocol
for	O
direct-drive	O
video	O
(	O
to	O
an	O
RGBI	O
monitor	B-Device
)	O
.	O
</s>
<s>
The	O
connector	O
on	O
the	O
card	O
is	O
female	O
and	O
the	O
one	O
on	O
the	O
monitor	B-Device
cable	O
is	O
male	O
.	O
</s>
<s>
The	O
Color	B-Device
Graphics	I-Device
Adapter	I-Device
uses	O
a	O
standard	O
RCA	B-Protocol
connector	I-Protocol
for	O
connection	O
to	O
an	O
NTSC-compatible	O
television	O
or	O
composite	O
video	O
monitor	B-Device
.	O
</s>
<s>
The	O
connector	O
on	O
the	O
card	O
is	O
female	O
and	O
the	O
one	O
on	O
the	O
monitor	B-Device
cable	O
is	O
male	O
.	O
</s>
