<s>
The	O
or	O
PS/55	B-Device
is	O
a	O
personal	B-Device
computer	I-Device
series	O
released	O
from	O
IBM	O
Japan	O
in	O
1987	O
.	O
</s>
<s>
The	O
PS/55	B-Device
is	O
the	O
successor	O
to	O
IBM	B-Device
5550	I-Device
(	O
Multistation	O
5550	O
)	O
,	O
but	O
its	O
architecture	O
is	O
based	O
upon	O
IBM	B-Device
PS/2	I-Device
,	O
perhaps	O
it	O
is	O
also	O
an	O
IBM	O
clone	O
.	O
</s>
<s>
The	O
first	O
line-up	O
of	O
the	O
series	O
consisted	O
of	O
rebranded	O
5550	O
models	O
except	O
the	O
Model	O
5570-S	O
which	O
was	O
based	O
on	O
the	O
PS/2	B-Device
Model	O
80	O
(	O
IBM	O
8580	O
)	O
.	O
</s>
<s>
Unlike	O
the	O
PS/2	B-Device
,	O
most	O
PS/2	B-Device
-based	O
models	O
have	O
a	O
32-bit	O
(	O
80386	B-General_Concept
or	O
80486	B-General_Concept
)	O
CPU	O
and	O
Micro	B-Device
Channel	I-Device
(	O
MCA	B-Device
)	O
bus	O
for	O
the	O
high-end	O
business	O
computing	O
market	O
.	O
</s>
<s>
IBM	O
Japan	O
was	O
hesitating	O
to	O
sell	O
personal	B-Device
computers	I-Device
for	O
consumers	O
because	O
the	O
IBM	B-Device
JX	I-Device
failed	O
.	O
</s>
<s>
The	O
AT	B-Architecture
bus	I-Architecture
model	O
was	O
released	O
for	O
home	O
users	O
in	O
1991	O
.	O
</s>
<s>
The	O
MCA	B-Device
video	O
card	O
called	O
Display	O
Adapter	O
has	O
a	O
Japanese	O
font	O
containing	O
nearly	O
7,000	O
glyphs	O
stored	O
in	O
its	O
ROM	B-Device
,	O
which	O
enables	O
PS/2	B-Device
-based	O
computers	O
to	O
display	O
Japanese	O
text	O
without	O
loading	O
the	O
font	O
into	O
memory	O
.	O
</s>
<s>
Similar	O
to	O
the	O
IBM	B-Device
5550	I-Device
,	O
the	O
display	O
resolution	O
in	O
character	O
mode	O
is	O
1040×725	O
pixels	B-Algorithm
(	O
12×24	O
and	O
24×24	O
pixel	B-Algorithm
Mincho	O
font	O
,	O
80×25	O
text	O
)	O
in	O
8	O
colors	O
.	O
</s>
<s>
The	O
graphics	O
mode	O
is	O
1024×768	O
pixels	B-Algorithm
in	O
16	O
colors	O
.	O
</s>
<s>
This	O
is	O
the	O
same	O
resolution	O
as	O
8514/A	B-Device
and	O
XGA/A	B-Device
,	O
but	O
not	O
compatible	O
.	O
</s>
<s>
The	O
first	O
Display	O
Adapter	O
was	O
installed	O
in	O
the	O
model	O
5570-S	O
,	O
also	O
known	O
as	O
the	O
first	O
Micro	B-Device
Channel	I-Device
machine	O
of	O
PS/55	B-Device
.	O
</s>
<s>
It	O
had	O
a	O
compatibility	O
problem	O
with	O
PS/2	B-Device
applications	O
.	O
</s>
<s>
Since	O
the	O
model	O
5550-S	O
released	O
in	O
1988	O
,	O
the	O
Display	O
Adapter	O
II	O
that	O
improved	O
the	O
PS/2	B-Device
compatibility	O
was	O
introduced	O
.	O
</s>
<s>
In	O
the	O
boot	B-Operating_System
sequence	I-Operating_System
,	O
the	O
Display	O
Adapter	O
enables	O
VGA	B-Protocol
on	O
the	O
motherboard	O
,	O
and	O
it	O
passes	O
the	O
video	O
signal	O
from	O
the	O
motherboard	O
to	O
adapter	O
's	O
VGA	B-Protocol
connector	I-Protocol
.	O
</s>
<s>
When	O
using	O
Japanese	O
DOS	O
,	O
VGA	B-Protocol
is	O
disabled	O
,	O
and	O
the	O
Display	O
Adapter	O
switches	O
its	O
video	O
selector	O
from	O
VGA	B-Protocol
to	O
own	O
video	O
chip	O
.	O
</s>
<s>
In	O
addition	O
,	O
it	O
added	O
the	O
256	O
color	O
mode	O
(	O
1024×768	O
pixels	B-Algorithm
in	O
256	O
colors	O
chosen	O
from	O
262,144	O
colors	O
)	O
.	O
</s>
<s>
Most	O
PS/2	B-Device
-based	O
models	O
have	O
compatibility	O
with	O
the	O
Display	O
Adapter	O
II	O
.	O
</s>
<s>
VGA	B-Protocol
and	O
the	O
following	O
display	O
modes	O
are	O
supported	O
:	O
</s>
<s>
Later	O
,	O
XGA	B-Device
and	O
VGA-only	O
models	O
were	O
released	O
.	O
</s>
<s>
These	O
later	O
machines	O
cannot	O
run	O
the	O
special	O
Japanese	O
DOS	O
,	O
instead	O
requiring	O
the	O
use	O
of	O
DOS/V	B-Application
with	O
software-rendered	O
kanji	O
.	O
</s>
<s>
The	O
following	O
keyboards	O
have	O
the	O
PS/2	B-Protocol
port	I-Protocol
.	O
</s>
<s>
These	O
keyboards	O
have	O
new	O
scancode	O
sets	O
(	O
81h	O
,	O
82h	O
,	O
8Ah	O
)	O
to	O
support	O
additional	O
keys	O
for	O
Japanese	O
input	B-General_Concept
method	I-General_Concept
.	O
</s>
<s>
5576-002	O
-	O
Japanese	O
layout	O
based	O
on	O
101	B-Device
Enhanced	I-Device
keyboard	I-Device
,	O
but	O
uses	O
Alps	O
Electric	O
Co	O
.	O
mechanical	O
key	O
switches	O
.	O
</s>
<s>
5576-A01	O
-	O
OADG	B-Device
reference	O
keyboard	O
.	O
</s>
<s>
5510-Z	O
,	O
S	O
,	O
T	O
(	O
VGA	B-Protocol
model	O
.	O
</s>
<s>
PS/55	B-Device
Note	I-Device
(	O
Predecessor	O
to	O
ThinkPad	B-Operating_System
.	O
</s>
<s>
AT	B-Architecture
bus	I-Architecture
or	O
MCA	B-Device
bus	I-Device
.	O
)	O
</s>
