<s>
The	O
APC	O
(	O
Advanced	O
Personal	B-Device
Computer	I-Device
)	O
was	O
a	O
series	O
of	O
business	O
microcomputers	O
released	O
outside	O
of	O
Japan	O
by	O
the	O
NEC	O
Corporation	O
.	O
</s>
<s>
The	O
series	O
comprised	O
the	O
APC	O
,	O
the	O
APC	O
II	O
and	O
APC	B-Operating_System
III	I-Operating_System
,	O
international	O
versions	O
of	O
models	O
from	O
the	O
Japanese	O
NEC	O
N5200	B-Operating_System
series	O
.	O
</s>
<s>
The	O
8086-based	O
N5200	B-Operating_System
,	O
released	O
in	O
1981	O
,	O
was	O
the	O
first	O
computer	O
to	O
use	O
the	O
NEC	B-Device
µPD7220	I-Device
High-Performance	O
Graphics	O
Display	O
Controller	O
.	O
</s>
<s>
The	O
much	O
better	O
known	O
PC-9800	B-Operating_System
series	I-Operating_System
,	O
released	O
a	O
year	O
later	O
by	O
the	O
different	O
division	O
,	O
had	O
a	O
similar	O
architecture	O
to	O
the	O
original	O
N5200	B-Operating_System
and	O
used	O
many	O
of	O
the	O
same	O
components	O
.	O
</s>
<s>
The	O
most	O
significant	O
differences	O
between	O
the	O
two	O
were	O
that	O
the	O
PC-9801	B-Operating_System
had	O
slightly	O
lower	O
vertical	O
screen	O
resolution	O
,	O
graphics	O
were	O
standard	O
instead	O
of	O
optional	O
(	O
still	O
using	O
a	O
second	O
µPD7220	O
)	O
and	O
it	O
used	O
5.25	O
"	O
floppy	O
drives	O
instead	O
of	O
8	O
"	O
.	O
</s>
<s>
The	O
APC	O
IV	O
,	O
despite	O
sharing	O
the	O
series	O
name	O
,	O
was	O
an	O
ordinary	O
IBM	B-Operating_System
PC/AT	I-Operating_System
compatible	O
and	O
not	O
compatible	O
with	O
the	O
earlier	O
APC	O
models	O
.	O
</s>
<s>
The	O
N5200	B-Operating_System
is	O
a	O
series	O
of	O
personal	B-Device
computers	I-Device
released	O
in	O
1981	O
.	O
</s>
<s>
The	O
APC	O
is	O
a	O
version	O
of	O
the	O
N5200	B-Operating_System
that	O
was	O
sold	O
outside	O
Japan	O
.	O
</s>
<s>
Although	O
its	O
computer	O
architecture	O
is	O
very	O
similar	O
to	O
the	O
PC-98	B-Operating_System
,	O
it	O
was	O
developed	O
and	O
marketed	O
in	O
a	O
different	O
way	O
.	O
</s>
<s>
The	O
N5200	B-Operating_System
was	O
marketed	O
as	O
a	O
personal	B-Device
computer	I-Device
which	O
could	O
be	O
used	O
as	O
both	O
a	O
standalone	O
computer	O
and	O
a	O
computer	B-General_Concept
terminal	I-General_Concept
for	O
ACOS	B-Application
mainframe	O
platforms	O
.	O
</s>
<s>
It	O
was	O
developed	O
by	O
the	O
Terminal	O
Units	O
Division	O
who	O
developed	O
computer	B-General_Concept
terminals	I-General_Concept
for	O
mainframes	O
,	O
but	O
the	O
PC-98	B-Operating_System
was	O
developed	O
by	O
the	O
Small	O
Systems	O
Division	O
who	O
developed	O
standalone	O
enterprise	O
systems	O
.	O
</s>
<s>
The	O
position	O
of	O
the	O
N5200	B-Operating_System
is	O
similar	O
to	O
IBM	B-Device
3270	I-Device
PC	I-Device
,	O
but	O
there	O
is	O
significant	O
difference	O
that	O
the	O
N5200	B-Operating_System
did	O
n't	O
offer	O
the	O
PC-98	B-Operating_System
compatibility	O
instead	O
it	O
had	O
own	O
software	O
library	O
.	O
</s>
<s>
As	O
of	O
1982	O
,	O
both	O
CP/M	B-Operating_System
-86	I-Operating_System
and	O
MS-DOS	B-Application
lacked	O
task	O
switching	O
and	O
an	O
ISAM	B-Application
support	O
,	O
so	O
NEC	O
developed	O
a	O
proprietary	O
operating	O
system	O
for	O
the	O
N5200	B-Operating_System
,	O
called	O
PTOS	O
.	O
</s>
<s>
PTOS	O
was	O
ported	O
to	O
the	O
PC-98	B-Operating_System
in	O
the	O
early	O
1990s	O
,	O
and	O
the	O
N5200	B-Operating_System
computer	O
line	O
was	O
absorbed	O
.	O
</s>
<s>
It	O
used	O
a	O
16-bit	O
NEC	O
μPD	O
8086	B-General_Concept
CPU	O
with	O
128K	O
of	O
RAM	O
(	O
expandable	O
to	O
256K	O
)	O
,	O
8K	O
of	O
ROM	O
,	O
and	O
4K	O
of	O
battery-backed	O
CMOS	O
RAM	O
,	O
a	O
clock/calendar	O
chip	O
,	O
parallel	O
printer	O
and	O
RS-232	O
serial	O
interfaces	O
,	O
and	O
one	O
or	O
two	O
built-in	O
8	O
"	O
floppy	O
diskette	O
drives	O
supporting	O
both	O
single-sided	O
single-density	O
(	O
243	O
KB	O
)	O
and	O
double-sided	O
double-density	O
(	O
1	O
MB	O
)	O
formats	O
.	O
</s>
<s>
A	O
built-in	O
12	O
"	O
monochrome	O
or	O
8-colour	O
display	O
was	O
driven	O
by	O
an	O
NEC	B-Device
µPD7220	I-Device
display	O
controller	O
generating	O
an	O
80	O
column	O
by	O
25	O
line	O
character	O
display	O
.	O
</s>
<s>
Operating	O
systems	O
included	O
CP/M	B-Operating_System
-86	I-Operating_System
and	O
MS-DOS	B-Application
.	O
</s>
<s>
The	O
APC	B-Operating_System
III	I-Operating_System
(	O
Advanced	O
Personal	B-Device
Computer	I-Device
)	O
was	O
released	O
by	O
NEC	O
in	O
1984	O
.	O
</s>
<s>
An	O
update	O
on	O
the	O
NEC	B-Operating_System
APC	I-Operating_System
II	O
,	O
which	O
replaced	O
the	O
original	O
NEC	B-Operating_System
APC	I-Operating_System
,	O
all	O
the	O
NEC	B-Operating_System
APC	I-Operating_System
models	O
utilized	O
the	O
Intel	B-General_Concept
8086	I-General_Concept
processor	O
,	O
unlike	O
the	O
IBM	B-Device
PC	I-Device
and	O
clones	O
.	O
</s>
<s>
The	O
unit	O
was	O
physically	O
smaller	O
than	O
an	O
IBM-PC	B-Device
.	O
</s>
<s>
C-bus	O
expansion	O
cards	O
(	O
PCBs	O
)	O
could	O
be	O
inserted	O
without	O
removal	O
of	O
the	O
exterior	O
case	O
,	O
as	O
was	O
required	O
for	O
the	O
IBM	B-Device
PC	I-Device
.	O
</s>
<s>
As	O
with	O
the	O
IBM	B-Device
PC	I-Device
,	O
the	O
maximum	O
usable	O
memory	O
was	O
640KB	O
(	O
the	O
address	O
range	O
of	O
the	O
Intel	O
8088	O
and	O
8086	B-General_Concept
is	O
1MB	O
)	O
.	O
</s>
<s>
RS-232	O
serial	O
,	O
'	O
Centronics	O
 '	O
parallel	O
and	O
video	O
interfaces	O
were	O
built	O
onto	O
the	O
motherboard	O
,	O
whereas	O
expansion	O
cards	O
were	O
required	O
for	O
almost	O
every	O
function	O
of	O
an	O
IBM	B-Device
PC	I-Device
except	O
for	O
the	O
CPU	O
,	O
BIOS	O
and	O
built-in	O
RAM	O
.	O
</s>
<s>
The	O
APC	B-Operating_System
III	I-Operating_System
's	O
'	O
on-board	O
'	O
video	O
controller	O
meant	O
that	O
upgrades	O
(	O
other	O
than	O
internally	O
mounted	O
video	O
memory	O
)	O
could	O
not	O
be	O
achieved	O
,	O
and	O
the	O
display	O
was	O
stuck	O
at	O
640×400×3	O
.	O
</s>
<s>
The	O
NEC	B-Operating_System
APC	I-Operating_System
series	O
supported	O
a	O
proprietary	O
NEC	B-Device
APC	I-Device
character	I-Device
set	I-Device
and	O
user-definable	O
fonts	O
in	O
text	O
mode	O
.	O
</s>
<s>
By	O
comparison	O
,	O
the	O
original	O
IBM	O
supported	O
an	O
8-bit	O
data	O
bus	O
with	O
20-bit	O
address	O
,	O
which	O
was	O
later	O
revised	O
to	O
16	O
data	O
bits	O
and	O
24	O
address	O
bits	O
in	O
the	O
PC	B-Operating_System
AT	I-Operating_System
.	O
</s>
<s>
This	O
was	O
initially	O
limited	O
to	O
the	O
10MB	O
ST-506	B-Device
hard	O
disks	O
.	O
</s>
<s>
This	O
capacity	O
could	O
be	O
increased	O
to	O
20MB	O
(	O
but	O
no	O
higher	O
)	O
after	O
upgrading	O
to	O
MS-DOS	B-Application
3.1	O
.	O
</s>
<s>
Shipped	O
standard	O
with	O
MS-DOS	B-Application
2.11	O
,	O
other	O
operating	O
systems	O
were	O
available	O
,	O
such	O
as	O
the	O
Unix	B-Application
derivative	O
,	O
PC-UX	B-Operating_System
.	O
</s>
<s>
Later	O
,	O
MS	B-Application
DOS	I-Application
3.1	O
was	O
released	O
for	O
the	O
APC	O
.	O
</s>
<s>
The	O
APC	B-Operating_System
III	I-Operating_System
was	O
not	O
fully	O
compatible	O
with	O
the	O
IBM-PC	B-Device
,	O
either	O
on	O
a	O
hardware	O
level	O
(	O
although	O
some	O
parts	O
were	O
compatible	O
)	O
,	O
or	O
a	O
software	O
level	O
(	O
although	O
again	O
,	O
some	O
software	O
was	O
compatible	O
)	O
.	O
</s>
<s>
The	O
earlier	O
penetration	O
of	O
the	O
market	O
saw	O
PC	O
clones	O
adopt	O
the	O
IBM	B-Device
PC	I-Device
architecture	O
.	O
</s>
<s>
In	O
the	O
export	O
markets	O
,	O
NEC	O
fell	O
into	O
line	O
with	O
the	O
16-bit	O
IBM-AT	B-Operating_System
architecture	O
and	O
did	O
not	O
pursue	O
the	O
APC-III	O
architecture	O
any	O
further	O
.	O
</s>
<s>
The	O
APC	O
IV	O
,	O
released	O
in	O
1986	O
,	O
was	O
an	O
IBM	B-Operating_System
PC/AT	I-Operating_System
clone	O
that	O
was	O
not	O
designed	O
to	O
be	O
compatible	O
with	O
previous	O
APC	O
models	O
.	O
</s>
