<s>
The	O
IBM	B-Device
RT	I-Device
PC	I-Device
(	O
RISC	B-Architecture
Technology	O
Personal	O
Computer	O
)	O
is	O
a	O
family	O
of	O
workstation	B-Device
computers	I-Device
from	O
IBM	O
introduced	O
in	O
1986	O
.	O
</s>
<s>
These	O
were	O
the	O
first	O
commercial	O
computers	O
from	O
IBM	O
that	O
were	O
based	O
on	O
a	O
reduced	B-Architecture
instruction	I-Architecture
set	I-Architecture
computer	I-Architecture
(	O
RISC	B-Architecture
)	O
architecture	O
.	O
</s>
<s>
The	O
RT	B-Device
PC	I-Device
uses	O
IBM	O
's	O
proprietary	O
ROMP	B-Device
microprocessor	B-Architecture
,	O
which	O
commercialized	O
technologies	O
pioneered	O
by	O
IBM	O
Research	O
's	O
801	B-Device
experimental	O
minicomputer	O
(	O
the	O
801	B-Device
was	O
the	O
first	O
RISC	B-Architecture
)	O
.	O
</s>
<s>
The	O
RT	B-Device
PC	I-Device
runs	O
three	O
operating	B-General_Concept
systems	I-General_Concept
:	O
AIX	B-Application
,	O
the	O
Academic	O
Operating	B-General_Concept
System	I-General_Concept
(	O
AOS	O
)	O
,	O
and	O
Pick	B-Application
.	O
</s>
<s>
The	O
RT	B-Device
PC	I-Device
's	O
specifications	O
were	O
regarded	O
as	O
"	O
less	O
than	O
impressive	O
"	O
compared	O
to	O
contemporary	O
workstations	B-Device
by	O
its	O
competitors	O
in	O
that	O
particular	O
market	O
,	O
although	O
the	O
product	O
was	O
deemed	O
deserving	O
of	O
"	O
a	O
healthy	O
amount	O
of	O
respect	O
"	O
,	O
particularly	O
with	O
the	O
prospect	O
of	O
IBM	O
as	O
"	O
a	O
serious	O
competitor	O
"	O
who	O
,	O
despite	O
having	O
a	O
product	O
whose	O
performance	O
was	O
an	O
estimated	O
18	O
months	O
behind	O
other	O
vendors	O
,	O
would	O
potentially	O
be	O
able	O
to	O
catch	O
up	O
quickly	O
by	O
applying	O
the	O
company	O
's	O
renowned	O
technological	O
capabilities	O
.	O
</s>
<s>
Given	O
such	O
performance	O
limitations	O
,	O
the	O
RT	B-Device
PC	I-Device
had	O
little	O
commercial	O
success	O
as	O
a	O
result	O
.	O
</s>
<s>
IBM	O
responded	O
by	O
introducing	O
the	O
RS/6000	B-Device
workstations	B-Device
in	O
1990	O
,	O
which	O
used	O
a	O
new	O
IBM-proprietary	O
RISC	B-Architecture
processor	I-Architecture
,	O
the	O
POWER1	B-General_Concept
.	O
</s>
<s>
All	O
RT	B-Device
PC	I-Device
models	O
were	O
discontinued	O
by	O
May	O
1991	O
.	O
</s>
<s>
Each	O
machine	O
had	O
one	O
processor	O
slot	O
,	O
one	O
co-processor	B-General_Concept
slot	O
,	O
and	O
two	O
RAM	O
slots	O
.	O
</s>
<s>
The	O
Standard	O
Processor	O
Card	O
or	O
032	B-Device
card	O
had	O
a	O
5.88MHz	O
clock	O
rate	O
(	O
170ns	O
cycle	O
time	O
)	O
,	O
1MB	O
of	O
standard	O
memory	O
(	O
expandable	O
via	O
1	O
,	O
2	O
,	O
or	O
4MB	O
memory	O
boards	O
)	O
.	O
</s>
<s>
It	O
could	O
be	O
accompanied	O
by	O
an	O
optional	O
Floating-Point	B-Algorithm
Accelerator	O
(	O
FPA	O
)	O
board	O
,	O
which	O
contained	O
a	O
10MHz	O
National	O
Semiconductor	O
NS32081	B-Device
floating	B-Algorithm
point	I-Algorithm
coprocessor	B-General_Concept
.	O
</s>
<s>
This	O
processor	O
card	O
was	O
used	O
in	O
the	O
original	O
RT	B-Device
PC	I-Device
models	O
(	O
010	O
,	O
020	O
,	O
025	O
,	O
and	O
A25	O
)	O
announced	O
on	O
January	O
21	O
,	O
1986	O
.	O
</s>
<s>
The	O
Advanced	O
Processor	O
Card	O
had	O
a	O
10MHz	O
clock	O
(	O
100ns	O
)	O
and	O
either	O
4MB	O
memory	O
on	O
the	O
processor	O
card	O
,	O
or	O
external	O
4MB	O
ECC	B-Error_Name
memory	O
cards	O
,	O
and	O
featured	O
a	O
built-in	O
20MHz	O
Motorola	B-General_Concept
68881	I-General_Concept
floating-point	B-Algorithm
processor	O
.	O
</s>
<s>
The	O
Advanced	O
Processor	O
Card	O
could	O
be	O
accompanied	O
by	O
an	O
optional	O
Advanced	O
Floating-Point	B-Algorithm
Accelerator	O
(	O
AFPA	O
)	O
board	O
,	O
which	O
was	O
based	O
around	O
the	O
Analog	O
Devices	O
ADSP-3220	O
FP	O
multiplier	O
and	O
ADSP-3221	O
FP	O
ALU	O
.	O
</s>
<s>
The	O
Enhanced	O
Advanced	O
Processor	O
Card	O
sported	O
a	O
12.5MHz	O
clock	O
(	O
80ns	O
)	O
,	O
16MB	O
on-board	O
memory	O
,	O
while	O
an	O
enhanced	O
advanced	O
floating	B-Algorithm
point	I-Algorithm
accelerator	O
was	O
standard	O
.	O
</s>
<s>
All	O
RT	B-Device
PCs	I-Device
supported	O
up	O
to	O
16MB	O
of	O
memory	O
.	O
</s>
<s>
I/O	O
was	O
provided	O
by	O
eight	O
ISA	B-Architecture
bus	I-Architecture
slots	O
.	O
</s>
<s>
External	O
SCSI	B-Architecture
cabinets	O
could	O
be	O
used	O
to	O
provide	O
more	O
storage	O
.	O
</s>
<s>
Also	O
standard	O
were	O
a	O
mouse	O
and	O
either	O
a	O
720×512	O
or	O
1024×768	O
pixel-addressable	O
display	O
,	O
and	O
a	O
4Mbit/s	O
Token	B-Device
Ring	I-Device
network	I-Device
adapter	O
or	O
10BASE2	O
Ethernet	O
adapter	O
.	O
</s>
<s>
For	O
running	O
CADAM	O
,	O
a	O
computer-aided	B-Application
design	I-Application
(	O
CAD	B-Application
)	O
program	O
,	O
an	O
IBM	O
5080	O
or	O
5085	O
graphics	O
processor	O
could	O
be	O
attached	O
.	O
</s>
<s>
The	O
5080	O
and	O
5085	O
were	O
contained	O
in	O
a	O
large	O
cabinet	O
that	O
would	O
have	O
been	O
positioned	O
alongside	O
the	O
RT	B-Device
PC	I-Device
.	O
</s>
<s>
The	O
6152	O
Academic	O
System	O
was	O
a	O
PS/2	O
Model	O
60	O
with	O
a	O
RISC	B-Architecture
Adapter	O
Card	O
,	O
a	O
Micro	B-Device
Channel	I-Device
board	O
containing	O
a	O
ROMP	B-Device
,	O
its	O
support	O
ICs	O
,	O
and	O
up	O
to	O
8MB	O
of	O
memory	O
.	O
</s>
<s>
It	O
allowed	O
the	O
PS/2	O
to	O
run	O
ROMP	B-Device
software	O
compiled	B-Language
for	O
the	O
AOS	O
.	O
</s>
<s>
AOS	O
was	O
downloaded	O
from	O
a	O
RT	B-Device
PC	I-Device
running	O
AOS	O
,	O
via	O
a	O
LAN	B-General_Concept
TCP/IP	B-Protocol
interface	O
.	O
</s>
<s>
One	O
of	O
the	O
novel	O
aspects	O
of	O
the	O
RT	O
design	O
was	O
the	O
use	O
of	O
a	O
microkernel	B-Operating_System
.	O
</s>
<s>
The	O
keyboard	O
,	O
mouse	O
,	O
display	O
,	O
disk	O
drives	O
and	O
network	O
were	O
all	O
controlled	O
by	O
a	O
microkernel	B-Operating_System
,	O
called	O
Virtual	B-Device
Resource	I-Device
Manager	I-Device
(	O
VRM	O
)	O
,	O
which	O
allowed	O
multiple	O
operating	B-General_Concept
systems	I-General_Concept
to	O
be	O
booted	O
and	O
run	O
at	O
the	O
same	O
time	O
.	O
</s>
<s>
One	O
could	O
"	O
hotkey	O
"	O
from	O
one	O
operating	B-General_Concept
system	I-General_Concept
to	O
the	O
next	O
using	O
the	O
Alt-Tab	O
key	O
combination	O
.	O
</s>
<s>
Both	O
AIX	B-Application
version	O
2	O
and	O
the	O
Pick	B-Application
operating	I-Application
system	I-Application
were	O
ported	O
to	O
this	O
microkernel	B-Operating_System
.	O
</s>
<s>
Pick	B-Application
was	O
unique	O
in	O
being	O
a	O
unified	O
operating	B-General_Concept
system	I-General_Concept
and	O
database	O
,	O
and	O
ran	O
various	O
accounting	O
applications	O
.	O
</s>
<s>
The	O
primary	O
operating	B-General_Concept
system	I-General_Concept
for	O
the	O
RT	O
was	O
AIX	B-Application
version	O
2	O
.	O
</s>
<s>
Much	O
of	O
the	O
AIX	B-Application
v2	O
kernel	O
was	O
written	O
in	O
a	O
variant	O
of	O
the	O
PL/I	B-Language
programming	I-Language
language	I-Language
,	O
which	O
proved	O
troublesome	O
during	O
the	O
migration	O
to	O
AIX	B-Application
v3	O
.	O
</s>
<s>
AIX	B-Application
v2	O
included	O
full	O
TCP/IP	B-Protocol
networking	O
support	O
,	O
as	O
well	O
as	O
SNA	B-Architecture
,	O
and	O
two	O
networking	O
file	O
systems	O
:	O
NFS	B-Protocol
,	O
licensed	O
from	O
Sun	O
Microsystems	O
,	O
and	O
IBM	O
Distributed	O
Services	O
(	O
DS	O
)	O
.	O
</s>
<s>
DS	O
had	O
the	O
distinction	O
of	O
being	O
built	O
on	O
top	O
of	O
SNA	B-Architecture
,	O
and	O
thereby	O
being	O
fully	O
compatible	O
with	O
DS	O
on	O
the	O
IBM	O
midrange	O
AS/400	B-Device
and	O
mainframe	O
systems	O
.	O
</s>
<s>
For	O
the	O
graphical	O
user	O
interfaces	O
,	O
AIX	B-Application
v2	O
came	O
with	O
the	O
X10R3	O
and	O
later	O
the	O
X10R4	O
and	O
X11	B-Operating_System
releases	O
of	O
the	O
X	B-Operating_System
Window	I-Operating_System
System	I-Operating_System
from	O
MIT	O
,	O
together	O
with	O
the	O
Athena	B-Library
widget	I-Library
set	I-Library
.	O
</s>
<s>
Compilers	B-Language
for	O
C	B-Language
and	O
Fortran	B-Application
programming	I-Application
languages	I-Application
were	O
available	O
.	O
</s>
<s>
Some	O
RT	B-Device
PCs	I-Device
were	O
also	O
shipped	O
with	O
the	O
Academic	O
Operating	B-General_Concept
System	I-General_Concept
(	O
AOS	O
)	O
,	O
an	O
IBM	O
port	O
of	O
4.3BSD	B-Operating_System
Unix	B-Application
to	O
the	O
RT	B-Device
PC	I-Device
.	O
</s>
<s>
It	O
was	O
offered	O
as	O
an	O
alternative	O
to	O
AIX	B-Application
,	O
the	O
usual	O
RT	B-Device
PC	I-Device
operating	B-General_Concept
system	I-General_Concept
,	O
to	O
US	O
universities	O
eligible	O
for	O
an	O
IBM	O
educational	O
discount	O
.	O
</s>
<s>
AOS	O
added	O
a	O
few	O
extra	O
features	O
to	O
4.3BSD	B-Operating_System
,	O
notably	O
NFS	B-Protocol
,	O
and	O
an	O
almost	O
ANSI	O
C-compliant	O
C	B-Language
compiler	B-Language
.	O
</s>
<s>
A	O
later	O
version	O
of	O
AOS	O
existed	O
that	O
was	O
derived	O
from	O
4.3BSD-Reno	O
,	O
but	O
it	O
was	O
not	O
widely	O
distributed	O
.	O
</s>
<s>
The	O
RT	O
forced	O
an	O
important	O
stepping-stone	O
in	O
the	O
development	O
of	O
the	O
X	B-Operating_System
Window	I-Operating_System
System	I-Operating_System
,	O
when	O
a	O
group	O
at	O
Brown	O
University	O
ported	O
X	B-Operating_System
version	O
9	O
to	O
the	O
system	O
.	O
</s>
<s>
The	O
IBM	B-Device
RT	I-Device
had	O
a	O
varied	O
life	O
even	O
from	O
its	O
initial	O
announcement	O
.	O
</s>
<s>
Many	O
thought	O
that	O
the	O
RT	O
was	O
part	O
of	O
IBM	B-Device
's	I-Device
Personal	I-Device
Computer	I-Device
line	O
of	O
computers	O
.	O
</s>
<s>
This	O
confusion	O
started	O
with	O
its	O
initial	O
name	O
,	O
"	O
IBM	B-Device
RT	I-Device
PC	I-Device
"	O
.	O
</s>
<s>
Both	O
MIT	O
's	O
Project	B-Operating_System
Athena	I-Operating_System
and	O
Brown	O
University	O
's	O
Institute	O
for	O
Research	O
in	O
Information	O
and	O
Scholarship	O
found	O
the	O
RT	O
inferior	O
to	O
other	O
computers	O
.	O
</s>
<s>
The	O
performance	O
of	O
the	O
RT	O
,	O
in	O
comparison	O
with	O
other	O
contemporaneous	O
Unix	B-Device
workstations	I-Device
,	O
was	O
not	O
outstanding	O
.	O
</s>
<s>
In	O
particular	O
,	O
the	O
floating	B-Algorithm
point	I-Algorithm
performance	O
was	O
poor	O
,	O
and	O
was	O
scandalized	O
mid-life	O
with	O
the	O
discovery	O
of	O
a	O
bug	O
in	O
the	O
floating	B-Algorithm
point	I-Algorithm
square	O
root	O
routine	O
.	O
</s>
<s>
With	O
the	O
RT	O
system	O
's	O
modest	O
processing	O
power	O
(	O
when	O
first	O
announced	O
)	O
,	O
and	O
with	O
announcements	O
later	O
that	O
year	O
by	O
some	O
other	O
workstation	B-Device
vendors	O
,	O
industry	O
analysts	O
questioned	O
IBM	O
's	O
directions	O
.	O
</s>
<s>
AIX	B-Application
for	O
the	O
RT	O
was	O
IBM	O
's	O
second	O
foray	O
into	O
UNIX	B-Application
(	O
its	O
first	O
was	O
PC/IX	O
for	O
the	O
IBM	B-Device
PC	I-Device
in	O
September	O
1984	O
.	O
)	O
</s>
<s>
The	O
lack	O
of	O
software	O
packages	O
and	O
IBM	O
's	O
sometimes	O
lackluster	O
support	O
of	O
AIX	B-Application
,	O
in	O
addition	O
to	O
sometimes	O
unusual	O
changes	O
from	O
traditional	O
,	O
de	O
facto	O
UNIX	B-Application
operating	I-Application
system	I-Application
standards	O
,	O
caused	O
most	O
software	O
suppliers	O
to	O
be	O
slow	O
in	O
embracing	O
the	O
RT	O
and	O
AIX	B-Application
.	O
</s>
<s>
The	O
RT	O
found	O
its	O
home	O
mostly	O
in	O
the	O
CAD/CAM	O
and	O
CATIA	B-Algorithm
markets	O
,	O
with	O
some	O
inroads	O
into	O
the	O
scientific	O
and	O
educational	O
areas	O
,	O
especially	O
after	O
the	O
announcement	O
of	O
AOS	O
and	O
substantial	O
discounts	O
for	O
the	O
educational	O
community	O
.	O
</s>
<s>
The	O
RT	O
running	O
the	O
Pick	B-Application
OS	I-Application
also	O
found	O
use	O
as	O
shopping	O
store	O
control	O
systems	O
,	O
given	O
the	O
strong	O
database	O
,	O
accounting	O
system	O
and	O
general	O
business	O
support	O
in	O
the	O
Pick	B-Application
OS	I-Application
.	O
</s>
<s>
The	O
RT	O
also	O
did	O
well	O
as	O
an	O
interface	O
system	O
between	O
IBM	O
's	O
larger	O
mainframes	O
,	O
due	O
to	O
its	O
SNA	B-Architecture
and	O
DS	O
support	O
,	O
and	O
some	O
of	O
its	O
point-of-sale	O
terminals	O
,	O
store	O
control	O
systems	O
,	O
and	O
machine	O
shop	O
control	O
systems	O
.	O
</s>
<s>
Pick	B-Application
OS	I-Application
sales	O
accounted	O
for	O
about	O
4,000	O
units	O
.	O
</s>
<s>
When	O
the	O
RT	B-Device
PC	I-Device
was	O
introduced	O
in	O
January	O
1986	O
,	O
it	O
competed	O
with	O
several	O
workstations	B-Device
from	O
established	O
providers	O
:	O
the	O
Apollo	O
Computer	O
Domain	B-Device
Series	I-Device
3000	I-Device
,	O
the	O
DEC	O
MicroVAX	B-Device
II	I-Device
,	O
and	O
Sun	O
Microsystems	O
Sun-3	B-Device
.	O
</s>
<s>
In	O
1987	O
,	O
"	O
The	O
NSF	O
starts	O
to	O
implement	O
its	O
T1	O
backbone	B-General_Concept
between	O
the	O
supercomputing	O
centers	O
with	O
24	O
RT-PCs	B-Device
in	O
parallel	O
implemented	O
by	O
IBM	O
as	O
‘	O
parallel	O
routers’	O
.	O
</s>
<s>
The	O
T1	O
idea	O
is	O
so	O
successful	O
that	O
proposals	O
for	O
T3	O
speeds	O
in	O
the	O
backbone	B-General_Concept
begin	O
.	O
</s>
<s>
From	O
July	O
1988	O
to	O
November	O
1992	O
,	O
the	O
NSFNET	O
's	O
T1	O
backbone	B-General_Concept
network	I-General_Concept
used	O
routers	B-Protocol
built	O
from	O
multiple	O
RT	B-Device
PCs	I-Device
(	O
typically	O
nine	O
)	O
interconnect	O
by	O
a	O
Token	B-Device
Ring	I-Device
LAN	B-General_Concept
.	O
</s>
