<s>
The	O
DECstation	B-Device
was	O
a	O
brand	O
of	O
computers	O
used	O
by	O
DEC	O
,	O
and	O
refers	O
to	O
three	O
distinct	O
lines	O
of	O
computer	O
systemsthe	O
first	O
released	O
in	O
1978	O
as	O
a	O
word	B-General_Concept
processing	I-General_Concept
system	O
,	O
and	O
the	O
latter	O
(	O
more	O
widely	O
known	O
)	O
two	O
both	O
released	O
in	O
1989	O
.	O
</s>
<s>
These	O
comprised	O
a	O
range	O
of	O
computer	B-Device
workstations	I-Device
based	O
on	O
the	O
MIPS	B-Device
architecture	I-Device
and	O
a	O
range	O
of	O
PC	O
compatibles	O
.	O
</s>
<s>
The	O
MIPS-based	O
workstations	B-Device
ran	O
ULTRIX	B-Operating_System
,	O
a	O
DEC-proprietary	O
version	O
of	O
UNIX	B-Application
,	O
and	O
early	O
releases	O
of	O
OSF/1	B-Operating_System
.	O
</s>
<s>
The	O
first	O
line	O
of	O
computer	O
systems	O
given	O
the	O
DECstation	B-Device
name	O
were	O
word	B-General_Concept
processing	I-General_Concept
systems	O
based	O
on	O
the	O
PDP-8	B-Device
.	O
</s>
<s>
systems	O
,	O
built	O
into	O
a	O
VT52	B-Application
terminal	B-General_Concept
,	O
were	O
also	O
known	O
as	O
the	O
VT78	B-Device
.	O
</s>
<s>
The	O
second	O
(	O
and	O
completely	O
unrelated	O
)	O
line	O
of	O
DECstations	B-Device
began	O
with	O
the	O
DECstation	B-Device
3100	I-Device
,	O
which	O
was	O
released	O
on	O
11	O
January	O
1989	O
.	O
</s>
<s>
The	O
DECstation	B-Device
3100	I-Device
was	O
the	O
first	O
commercially	O
available	O
RISC-based	B-Architecture
machine	O
built	O
by	O
DEC	O
.	O
</s>
<s>
This	O
line	O
of	O
DECstations	B-Device
was	O
the	O
fruit	O
of	O
an	O
advanced	O
development	O
skunkworks	O
project	O
carried	O
out	O
in	O
DEC	O
's	O
Palo	O
Alto	O
Hamilton	O
Ave	O
facility	O
.	O
</s>
<s>
Known	O
as	O
the	O
PMAX	O
project	O
,	O
its	O
focus	O
was	O
to	O
produce	O
a	O
computer	O
systems	O
family	O
with	O
the	O
economics	O
and	O
performance	O
to	O
compete	O
against	O
the	O
likes	O
of	O
Sun	O
Microsystems	O
and	O
other	O
RISC-based	B-Architecture
UNIX	B-Application
platforms	O
of	O
the	O
day	O
.	O
</s>
<s>
The	O
brainchild	O
of	O
James	O
Billmaier	O
,	O
Mario	O
Pagliaro	O
,	O
Armando	O
Stettner	O
and	O
Joseph	O
DiNucci	O
,	O
the	O
systems	O
family	O
was	O
to	O
also	O
employ	O
a	O
truly	O
RISC-based	B-Architecture
architecture	O
when	O
compared	O
to	O
the	O
heavier	O
and	O
very	O
CISC	B-Architecture
VAX	B-Device
or	O
the	O
then	O
still	O
under	O
development	O
PRISM	B-Architecture
architectures	O
.	O
</s>
<s>
At	O
the	O
time	O
DEC	O
was	O
mostly	O
known	O
for	O
their	O
CISC	B-Architecture
systems	O
including	O
the	O
successful	O
PDP-11	B-Device
and	O
VAX	B-Device
lines	O
.	O
</s>
<s>
Several	O
architectures	O
were	O
considered	O
from	O
Intel	B-General_Concept
,	O
Motorola	B-Architecture
and	O
others	O
but	O
the	O
group	O
quickly	O
selected	O
the	O
MIPS	O
line	O
of	O
microprocessors	O
.	O
</s>
<s>
Little-endian	O
mode	O
was	O
chosen	O
both	O
to	O
match	O
the	O
byte	O
ordering	O
of	O
VAX-based	O
systems	O
and	O
the	O
growing	O
number	O
of	O
Intel-based	O
PCs	O
and	O
computers	O
.	O
</s>
<s>
In	O
contrast	O
to	O
the	O
VAX	B-Device
and	O
the	O
later	O
DEC	B-Device
Alpha	I-Device
architectures	O
,	O
the	O
DECstation	B-Device
3100	I-Device
and	O
family	O
were	O
specifically	O
designed	O
and	O
built	O
to	O
run	O
a	O
UNIX	B-Application
system	I-Application
,	O
ULTRIX	B-Operating_System
,	O
and	O
no	O
version	O
of	O
the	O
VMS	B-Operating_System
operating	I-Operating_System
system	I-Operating_System
was	O
ever	O
released	O
for	O
DECstations	B-Device
.	O
</s>
<s>
As	O
the	O
core	O
advocates	O
later	O
left	O
the	O
company	O
,	O
the	O
MIPS-based	O
line	O
of	O
computers	O
was	O
shut	O
down	O
in	O
favor	O
of	O
the	O
Alpha-based	O
computers	O
,	O
a	O
DEC	O
invented	O
and	O
owned	O
architecture	O
,	O
descended	O
from	O
the	O
PRISM	B-Architecture
development	O
work	O
.	O
</s>
<s>
The	O
first	O
generation	O
of	O
commercially	O
marketed	O
DEC	B-Device
Alpha	I-Device
systems	O
,	O
the	O
DEC	B-Device
3000	I-Device
AXP	I-Device
series	O
,	O
were	O
similar	O
in	O
some	O
respects	O
to	O
contemporaneous	O
MIPS-based	O
DECstations	B-Device
,	O
which	O
were	O
sold	O
alongside	O
the	O
Alpha	B-Device
systems	O
as	O
the	O
DECstation	B-Device
line	O
was	O
gradually	O
phased	O
out	O
.	O
</s>
<s>
Both	O
used	O
the	O
TURBOchannel	B-Device
expansion	O
bus	O
for	O
video	O
and	O
network	O
cards	O
,	O
as	O
well	O
as	O
being	O
sold	O
with	O
the	O
same	O
TURBOchannel	B-Device
option	O
modules	O
,	O
mice	O
,	O
monitors	O
,	O
and	O
keyboards	O
.	O
</s>
<s>
Later	O
DECstations	B-Device
planned	O
to	O
be	O
based	O
on	O
the	O
ECL-based	O
R6000	O
were	O
canceled	O
on	O
14	O
August	O
1990	O
after	O
Bipolar	O
Integrated	O
Technology	O
failed	O
to	O
deliver	O
sufficient	O
volumes	O
of	O
the	O
microprocessor	O
,	O
which	O
was	O
difficult	O
to	O
fabricate	O
.	O
</s>
<s>
The	O
MIPS-based	O
DECstations	B-Device
were	O
used	O
as	O
the	O
first	O
target	O
system	O
and	O
development	O
platform	O
for	O
the	O
Mach	B-Operating_System
microkernel	I-Operating_System
,	O
as	O
well	O
as	O
early	O
development	O
of	O
the	O
Windows	B-Device
NT	I-Device
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
More	O
recently	O
,	O
various	O
free	O
operating	B-General_Concept
systems	I-General_Concept
such	O
as	O
NetBSD	B-Device
and	O
Linux/MIPS	O
have	O
been	O
ported	O
to	O
the	O
MIPS-based	O
DECstations	B-Device
,	O
extending	O
their	O
useful	O
life	O
by	O
providing	O
a	O
modern	O
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
DEC	O
originally	O
planned	O
to	O
introduce	O
OSF/1	B-Operating_System
as	O
its	O
chosen	O
Unix	B-Application
product	O
,	O
starting	O
with	O
a	O
1.0	O
version	O
in	O
March	O
1992	O
that	O
promised	O
to	O
offer	O
several	O
enhancements	O
over	O
ULTRIX	B-Operating_System
,	O
albeit	O
with	O
some	O
deficiencies	O
that	O
were	O
meant	O
to	O
be	O
fixed	O
in	O
a	O
2.0	O
version	O
scheduled	O
for	O
the	O
summer	O
of	O
that	O
year	O
.	O
</s>
<s>
However	O
,	O
during	O
a	O
period	O
of	O
strategic	O
uncertainty	O
only	O
weeks	O
later	O
in	O
1992	O
,	O
DEC	O
appeared	O
to	O
abandon	O
plans	O
to	O
officially	O
provide	O
OSF/1	B-Operating_System
on	O
MIPS-based	O
DECstations	B-Device
,	O
instead	O
re-emphasising	O
ULTRIX	B-Operating_System
for	O
these	O
models	O
whilst	O
intending	O
to	O
offer	O
OSF/1	B-Operating_System
for	O
the	O
company	O
's	O
impending	O
Alpha-based	O
product	O
lines	O
.	O
</s>
<s>
At	O
this	O
time	O
,	O
the	O
DECstation	B-Device
2100	O
,	O
3100	O
,	O
3100S	O
,	O
5000	O
–	O
120	O
,	O
5000	O
–	O
125	O
and	O
5000	O
–	O
200	O
models	O
were	O
stated	O
as	O
being	O
able	O
to	O
run	O
OSF/1	B-Operating_System
,	O
along	O
with	O
certain	O
DECsystem	B-Device
models	O
.	O
</s>
<s>
User	O
dissatisfaction	O
with	O
the	O
decision	O
,	O
driven	O
by	O
uncertainty	O
about	O
the	O
future	O
of	O
the	O
MIPS-based	O
DECstations	B-Device
and	O
ULTRIX	B-Operating_System
,	O
led	O
to	O
a	O
revision	O
of	O
the	O
company	O
's	O
strategy	O
,	O
with	O
DEC	O
promising	O
"	O
a	O
production-quality	O
version	O
of	O
OSF/1	B-Operating_System
"	O
with	O
support	O
for	O
all	O
of	O
the	O
company	O
's	O
Unix-based	O
workstations	B-Device
and	O
servers	O
.	O
</s>
<s>
Following	O
on	O
from	O
the	O
"	O
advanced	O
developer	O
's	O
kit	O
"	O
-	O
this	O
being	O
the	O
version	O
offering	O
support	O
for	O
only	O
certain	O
models	O
-	O
the	O
intention	O
was	O
to	O
produce	O
an	O
"	O
end-user	O
release	O
"	O
of	O
OSF/1	B-Operating_System
during	O
1993	O
for	O
R2000-	O
,	O
R3000	B-Device
-	O
and	O
R4000-based	O
models	O
,	O
offering	O
compatibility	O
with	O
OSF/1	B-Operating_System
on	O
Alpha	B-Device
.	O
</s>
<s>
Alongside	O
such	O
plans	O
,	O
DEC	O
would	O
also	O
continue	O
to	O
support	O
ULTRIX	B-Operating_System
on	O
its	O
R4000-based	O
systems	O
.	O
</s>
<s>
The	O
strategic	O
confusion	O
was	O
blamed	O
on	O
power	O
struggles	O
within	O
DEC	O
,	O
with	O
the	O
decision	O
made	O
to	O
abandon	O
further	O
OSF/1	B-Operating_System
work	O
on	O
DECstations	B-Device
being	O
attributed	O
to	O
an	O
executive	O
having	O
gained	O
control	O
over	O
the	O
Unix	B-Device
workstation	I-Device
group	O
,	O
thus	O
reportedly	O
causing	O
"	O
as	O
much	O
of	O
an	O
internal	O
uproar	O
as	O
it	O
did	O
an	O
external	O
one	O
"	O
.	O
</s>
<s>
At	O
the	O
end	O
of	O
1992	O
,	O
company	O
representatives	O
were	O
once	O
again	O
less	O
certain	O
about	O
the	O
prospects	O
of	O
delivering	O
OSF/1	B-Operating_System
on	O
the	O
DECstation	B-Device
range	O
,	O
with	O
the	O
projected	O
release	O
in	O
the	O
first	O
half	O
of	O
1993	O
"	O
up	O
in	O
the	O
air	O
"	O
and	O
under	O
threat	O
of	O
being	O
cancelled	O
if	O
sufficient	O
interest	O
were	O
not	O
forthcoming	O
from	O
software	O
vendors	O
.	O
</s>
<s>
Internally	O
,	O
the	O
marketing	O
group	O
for	O
the	O
DECstation	B-Device
had	O
been	O
able	O
to	O
convince	O
DEC	O
's	O
product	O
strategy	O
group	O
that	O
the	O
loss	O
in	O
sales	O
in	O
failing	O
to	O
offer	O
OSF/1	B-Operating_System
on	O
the	O
hardware	O
would	O
exceed	O
the	O
research	O
and	O
development	O
costs	O
involved	O
in	O
making	O
it	O
available	O
,	O
but	O
company-wide	O
spending	O
cuts	O
threatened	O
such	O
projects	O
.	O
</s>
<s>
Subsequent	O
indications	O
from	O
DEC	O
confirmed	O
,	O
without	O
further	O
elaboration	O
,	O
the	O
cancellation	O
of	O
the	O
product	O
alongside	O
increasing	O
uncertainty	O
around	O
further	O
hardware	O
upgrades	O
to	O
the	O
DECstation	B-Device
range	O
beyond	O
the	O
planned	O
R4400-based	O
products	O
.	O
</s>
<s>
Shortly	O
prior	O
to	O
the	O
release	O
of	O
the	O
DEC	B-Device
Alpha	I-Device
systems	O
,	O
a	O
port	O
of	O
OSF/1	B-Operating_System
to	O
the	O
DECstation	B-Device
was	O
completed	O
,	O
but	O
it	O
was	O
not	O
commercially	O
released	O
.	O
</s>
<s>
As	O
the	O
previously	O
announced	O
strategy	O
had	O
"	O
fizzled	O
"	O
,	O
DEC	O
representatives	O
had	O
reportedly	O
"	O
informed	O
ULTRIX	B-Operating_System
customers	O
that	O
they	O
should	O
start	O
planning	O
to	O
move	O
to	O
Alpha	B-Device
workstations	B-Device
running	O
OSF/1	B-Operating_System
in	O
1993	O
"	O
,	O
having	O
the	O
effect	O
of	O
undermining	O
customer	O
confidence	O
in	O
both	O
the	O
DECstation	B-Device
line	O
and	O
in	O
ULTRIX	B-Operating_System
,	O
but	O
also	O
raising	O
more	O
serious	O
concerns	O
about	O
the	O
company	O
's	O
broader	O
Unix	B-Application
strategy	O
.	O
</s>
<s>
Although	O
introduced	O
before	O
DEC	O
started	O
to	O
pursue	O
a	O
strategy	O
based	O
on	O
the	O
Advanced	B-Device
Computing	I-Device
Environment	I-Device
platform	O
,	O
the	O
company	O
's	O
stated	O
intention	O
was	O
that	O
DECstation	B-Device
users	O
could	O
potentially	O
migrate	O
to	O
an	O
OSF/1	B-Operating_System
-based	O
product	O
,	O
potentially	O
delivered	O
in	O
the	O
form	O
of	O
SCO	O
Open	O
Desktop	O
for	O
the	O
platform	O
,	O
offering	O
binary	O
compatibility	O
with	O
the	O
existing	O
ULTRIX	B-Operating_System
system	O
.	O
</s>
<s>
DEC	O
even	O
suggested	O
that	O
Windows	B-Device
NT	I-Device
would	O
be	O
available	O
for	O
DECstation	B-Device
models	O
.	O
</s>
<s>
The	O
GXemul	O
project	O
emulates	O
several	O
of	O
these	O
DECstation	B-Device
models	O
.	O
</s>
<s>
The	O
original	O
MIPS-based	O
DECstation	B-Device
3100	I-Device
was	O
followed	O
by	O
a	O
cost	O
reduced	O
2100	O
.	O
</s>
<s>
The	O
DECstation	B-Device
3100	I-Device
was	O
claimed	O
to	O
be	O
the	O
world	O
's	O
fastest	O
UNIX	B-Device
workstation	I-Device
at	O
the	O
time	O
.	O
</s>
<s>
Server	O
configurations	O
of	O
DECstation	B-Device
models	O
,	O
distributed	O
without	O
a	O
framebuffer	B-Algorithm
or	O
a	O
graphics	O
accelerator	O
,	O
both	O
Turbochannel	B-Device
and	O
Q-bus	B-Architecture
based	O
,	O
were	O
called	O
"	O
DECsystem	B-Device
"	O
but	O
should	O
not	O
be	O
confused	O
with	O
some	O
PDP-10	B-Device
machines	O
of	O
the	O
same	O
name	O
.	O
</s>
<s>
Early	O
models	O
of	O
the	O
DECstation	B-Device
were	O
heavily	O
integrated	O
systems	O
with	O
little	O
expansion	O
capability	O
and	O
do	O
not	O
even	O
possess	O
expansion	O
buses	O
.	O
</s>
<s>
The	O
DECstation	B-Device
5000	O
systems	O
,	O
introduced	O
later	O
,	O
improved	O
on	O
the	O
lack	O
of	O
expansion	O
capabilities	O
by	O
providing	O
the	O
TURBOchannel	B-Device
Interconnect	O
.	O
</s>
<s>
The	O
DECstation	B-Device
5000	O
systems	O
are	O
also	O
ARC	B-Device
(	O
Advanced	B-Device
RISC	I-Device
Computing	I-Device
)	O
compatible	O
.	O
</s>
<s>
The	O
last	O
DECstation	B-Device
models	O
focused	O
on	O
increased	O
component	O
integration	O
by	O
using	O
more	O
custom	O
ASICs	O
to	O
reduce	O
the	O
number	O
of	O
discrete	O
components	O
.	O
</s>
<s>
This	O
began	O
with	O
the	O
DECstation	B-Device
5000	O
Model	O
240	O
,	O
which	O
replaced	O
discrete	O
components	O
with	O
LSI	O
ASICs	O
and	O
ended	O
with	O
the	O
last	O
model	O
,	O
the	O
DECstation	B-Device
5000	O
Model	O
260	O
,	O
which	O
used	O
a	O
single	O
VLSI	O
ASIC	O
for	O
much	O
of	O
the	O
control	O
logic	O
.	O
</s>
<s>
Packaged	O
DECstation	B-Device
5000	O
systems	O
were	O
sometimes	O
suffixed	O
with	O
two	O
or	O
three	O
letters	O
.	O
</s>
<s>
Model	O
and	O
codenameProcessorMHzIntroducedWithdrawn3100	O
"	O
PMAX	O
"	O
R2000	B-Device
,	O
R2010	O
,	O
R2020	O
chipsetWorkstation	O
Systems	O
Engineering	O
:	O
"	O
DECstation	B-Device
3100	I-Device
Desktop	O
Workstation	B-Device
Functional	O
Specification	O
"	O
,	O
Revision	O
1.3	O
,	O
28	O
August	O
1990	O
,	O
Digital	O
Equipment	O
Corporation	O
16.67	O
MHz	O
(	O
60	O
ns	O
)	O
11	O
January	O
1989	O
?	O
2100	O
"	O
PMIN	O
"	O
R2000	B-Device
,	O
R2010	O
,	O
R2020	O
chipset12.50	O
MHz	O
(	O
80	O
ns	O
)	O
RISC	B-Architecture
Family	O
Performance	O
Summary	O
,	O
2	O
April	O
1990	O
,	O
Digital	O
Equipment	O
Corporation11	O
July	O
1989	O
?	O
</s>
<s>
The	O
DECstation	B-Device
3100	I-Device
and	O
2100	O
uses	O
a	O
R2000	B-Device
processor	O
,	O
a	O
R2010	O
floating	O
point	O
coprocessor	O
and	O
four	O
R2020	O
write	O
buffers	O
.	O
</s>
<s>
The	O
R2000	B-Device
uses	O
an	O
external	O
64	O
KB	O
direct-mapped	O
instruction	O
cache	O
and	O
a	O
64	O
KB	O
direct-mapped	O
write-through	O
data	O
cache	O
with	O
a	O
cache	O
line	O
size	O
of	O
four	O
bytes	O
.	O
</s>
<s>
Four	O
R2020	O
implement	O
a	O
four-stage	O
write	O
buffer	O
to	O
improve	O
performance	O
by	O
permitting	O
the	O
R2000	B-Device
to	O
write	O
to	O
its	O
write-through	O
data	O
cache	O
without	O
stalling	O
.	O
</s>
<s>
The	O
R2000	B-Device
microprocessor	I-Device
could	O
be	O
configured	O
to	O
run	O
either	O
in	O
big-endian	O
or	O
little-endian	O
mode	O
.	O
</s>
<s>
In	O
the	O
DECstation	B-Device
family	O
,	O
the	O
decision	O
was	O
made	O
to	O
run	O
little-endian	O
to	O
maintain	O
compatibility	O
with	O
both	O
the	O
VAX	B-Device
family	O
and	O
the	O
growing	O
population	O
of	O
Intel-based	O
PC	O
's	O
.	O
</s>
<s>
The	O
DECstation	B-Device
3100	I-Device
and	O
2100	O
's	O
memory	O
system	O
contains	O
both	O
the	O
DRAM-based	O
system	O
memory	O
and	O
VRAM-based	O
framebuffers	B-Algorithm
.	O
</s>
<s>
These	O
systems	O
has	O
12	O
SIMM	B-General_Concept
slots	O
that	O
use	O
2	O
MB	O
SIMMs	B-General_Concept
,	O
with	O
each	O
SIMM	B-General_Concept
containing	O
1,048,576	O
word	O
×	O
18-bit	O
DRAMs	O
.	O
</s>
<s>
The	O
SIMMs	B-General_Concept
are	O
installed	O
in	O
pairs	O
(	O
in	O
increments	O
of	O
4	O
MB	O
)	O
and	O
the	O
memory	O
system	O
is	O
byte-parity	O
protected	O
.	O
</s>
<s>
The	O
monochrome	O
framebuffer	B-Algorithm
are	O
implemented	O
with	O
a	O
256	O
KB	O
VFB01	O
SIMM	B-General_Concept
and	O
the	O
color	O
framebuffer	B-Algorithm
,	O
a	O
1	O
MB	O
VBF02	O
SIMM	B-General_Concept
.	O
</s>
<s>
If	O
one	O
of	O
these	O
framebuffer	B-Algorithm
SIMMs	B-General_Concept
are	O
not	O
present	O
,	O
the	O
framebuffer	B-Algorithm
cannot	O
be	O
used	O
.	O
</s>
<s>
The	O
SIMM	B-General_Concept
slots	O
were	O
rated	O
for	O
25	O
removal	O
and	O
insertion	O
cycles	O
,	O
with	O
five	O
being	O
the	O
recommended	O
limit	O
.	O
</s>
<s>
Graphics	O
capability	O
was	O
provided	O
by	O
two	O
frame	B-Algorithm
buffer	I-Algorithm
modules	O
,	O
the	O
monochrome	O
and	O
color	O
frame	B-Algorithm
buffer	I-Algorithm
.	O
</s>
<s>
The	O
monochrome	O
frame	B-Algorithm
buffer	I-Algorithm
supports	O
1-bit	O
color	O
and	O
a	O
resolution	O
of	O
1024	O
×	O
864	O
pixels	O
,	O
while	O
the	O
color	O
frame	B-Algorithm
buffer	I-Algorithm
supports	O
8-bit	O
color	O
and	O
the	O
same	O
resolution	O
as	O
the	O
monochrome	O
frame	B-Algorithm
buffer	I-Algorithm
.	O
</s>
<s>
Both	O
frame	B-Algorithm
buffers	I-Algorithm
use	O
the	O
Brooktree	O
Bt478	O
RAMDAC	B-Device
with	O
three	O
256-entry	O
,	O
8-bit	O
color	O
maps	O
.	O
</s>
<s>
The	O
color	O
frame	B-Algorithm
buffer	I-Algorithm
has	O
an	O
8-bit	O
write	O
mask	O
,	O
also	O
known	O
as	O
a	O
"	O
planemask	O
"	O
,	O
used	O
to	O
select	O
which	O
pixels	O
are	O
to	O
be	O
updated	O
.	O
</s>
<s>
None	O
of	O
the	O
framebuffers	B-Algorithm
use	O
all	O
the	O
memory	O
provided	O
by	O
the	O
frame	B-Algorithm
buffer	I-Algorithm
module	O
,	O
this	O
being	O
organized	O
as	O
1024	O
×	O
1024	O
pixels	O
,	O
and	O
thus	O
only	O
the	O
uppermost	O
864	O
pixels	O
are	O
used	O
for	O
the	O
display	O
.	O
</s>
<s>
Unused	O
areas	O
of	O
the	O
frame	B-Algorithm
buffer	I-Algorithm
memory	O
may	O
be	O
used	O
to	O
store	O
graphical	O
structures	O
such	O
as	O
fonts	O
,	O
although	O
this	O
was	O
considered	O
to	O
offer	O
"	O
no	O
performance	O
advantage	O
over	O
main	O
memory	O
"	O
and	O
,	O
in	O
the	O
context	O
of	O
the	O
X	O
server	O
implemented	O
by	O
Digital	O
,	O
would	O
have	O
complicated	O
the	O
memory	O
management	O
involved	O
.	O
</s>
<s>
The	O
frame	B-Algorithm
buffers	I-Algorithm
are	O
not	O
parity-protected	O
,	O
unlike	O
the	O
rest	O
of	O
the	O
system	O
memory	O
.	O
</s>
<s>
These	O
DECstations	B-Device
have	O
onboard	O
10	O
Mbit/s	O
Ethernet	O
provided	O
by	O
an	O
AMD	O
7990	O
LANCE	O
(	O
Local	O
Area	O
Network	O
Controller	O
for	O
Ethernet	O
)	O
and	O
an	O
AMD	O
7992	O
SIA	O
(	O
Serial	B-Protocol
Interface	I-Protocol
Adapter	I-Protocol
)	O
,	O
which	O
implements	O
the	O
interface	O
,	O
a	O
BNC	O
ThinWire	O
Ethernet	O
connector	O
.	O
</s>
<s>
These	O
systems	O
have	O
four	O
asynchronous	O
serial	B-Protocol
lines	I-Protocol
that	O
are	O
provided	O
by	O
a	O
DC7085	O
gate	O
array	O
.	O
</s>
<s>
Of	O
the	O
four	O
serial	B-Protocol
lines	I-Protocol
,	O
only	O
the	O
third	O
line	O
has	O
the	O
required	O
modem	O
control	O
signals	O
to	O
support	O
a	O
modem	O
.	O
</s>
<s>
The	O
real	O
time	O
clock	O
is	O
a	O
Motorola	B-Architecture
MC146818	O
,	O
which	O
also	O
has	O
50	O
bytes	O
of	O
RAM	O
for	O
storing	O
console	O
configuration	O
information	O
,	O
and	O
the	O
256	O
KB	O
of	O
ROM	O
for	O
storing	O
boot-strap	O
and	O
self-test	O
software	O
is	O
provided	O
by	O
two	O
128	O
KB	O
ROMs	O
in	O
DIP	O
sockets	O
.	O
</s>
<s>
The	O
enclosure	O
used	O
by	O
the	O
DECstation	B-Device
3100	I-Device
and	O
2100	O
is	O
identical	O
to	O
the	O
enclosure	O
used	O
by	O
the	O
VAXstation	O
3100	O
as	O
these	O
systems	O
use	O
a	O
mechanically	O
identical	O
system	O
module	O
.	O
</s>
<s>
The	O
Personal	O
DECstation	B-Device
5000	O
Series	O
are	O
entry-level	O
workstations	B-Device
,	O
code	O
named	O
"	O
MAXine	O
"	O
.	O
</s>
<s>
The	O
Personal	O
DECstation	B-Device
uses	O
a	O
low-profile	O
desktop	O
case	O
,	O
which	O
contained	O
a	O
power	O
supply	O
on	O
the	O
left	O
and	O
two	O
mounts	O
for	O
two	O
fixed	O
drives	O
,	O
or	O
one	O
fixed	O
drive	O
and	O
one	O
diskette	O
drive	O
,	O
at	O
the	O
front	O
.	O
</s>
<s>
The	O
first	O
model	O
contains	O
a	O
chipset	O
consisting	O
of	O
a	O
20	O
,	O
25	O
or	O
33MHz	O
R3000A	B-Device
CPU	O
and	O
R3010	B-Device
FPU	O
accompanied	O
by	O
a	O
64	O
KB	O
instruction	O
cache	O
and	O
a	O
64	O
KB	O
data	O
cache	O
.	O
</s>
<s>
The	O
CPUCTL	O
ASIC	O
also	O
implements	O
a	O
12.5MHz	O
TURBOchannel	B-Device
that	O
serves	O
as	O
the	O
system	O
interconnect	O
.	O
</s>
<s>
The	O
second	O
model	O
is	O
a	O
revised	O
version	O
of	O
the	O
first	O
module	O
with	O
a	O
20	O
or	O
25MHz	O
R3000A	B-Device
and	O
R3010	B-Device
that	O
used	O
plastic	O
packaging	O
,	O
whereas	O
the	O
previous	O
model	O
used	O
ceramic	O
packaging	O
.	O
</s>
<s>
The	O
third	O
model	O
contains	O
a	O
R4000	B-General_Concept
microprocessor	O
with	O
internal	O
instruction	O
and	O
data	O
caches	O
complemented	O
by	O
a	O
1	O
MB	O
secondary	O
cache	O
.	O
</s>
<s>
These	O
systems	O
have	O
8	O
MB	O
of	O
onboard	O
memory	O
and	O
four	O
SIMM	B-General_Concept
slots	O
that	O
can	O
be	O
used	O
to	O
expand	O
the	O
amount	O
of	O
memory	O
by	O
32	O
MB	O
,	O
for	O
a	O
total	O
of	O
40	O
MB	O
of	O
memory	O
.	O
</s>
<s>
These	O
SIMM	B-General_Concept
slots	O
accept	O
2	O
and	O
8	O
MB	O
SIMMs	B-General_Concept
in	O
pairs	O
.	O
</s>
<s>
All	O
SIMMs	B-General_Concept
in	O
the	O
system	O
must	O
be	O
of	O
the	O
same	O
size	O
.	O
</s>
<s>
The	O
Memory	O
Control	O
ASIC	O
controls	O
the	O
memory	O
and	O
communicates	O
with	O
the	O
CPU	O
subsystem	O
via	O
the	O
TURBOchannel	B-Device
bus	O
.	O
</s>
<s>
Expansion	O
is	O
provided	O
by	O
two	O
TURBOchannel	B-Device
slots	O
,	O
each	O
with	O
64	O
MB	O
of	O
physical	O
address	O
space	O
.	O
</s>
<s>
The	O
Personal	O
DECstation	B-Device
features	O
an	O
integrated	O
8-bit	O
color	O
frame	B-Algorithm
buffer	I-Algorithm
capable	O
of	O
a	O
resolution	O
of	O
1024	O
×	O
768	O
at	O
a	O
refresh	O
rate	O
of	O
72Hz	O
.	O
</s>
<s>
The	O
frame	B-Algorithm
buffer	I-Algorithm
consists	O
of	O
1	O
MB	O
of	O
VRAM	O
organized	O
as	O
262,144	O
32-bit	O
words	O
,	O
with	O
each	O
32-bit	O
word	O
containing	O
four	O
8-bit	O
pixels	O
.	O
</s>
<s>
The	O
frame	B-Algorithm
buffer	I-Algorithm
uses	O
an	O
INMOS	O
IMS	O
G332	B-Device
RAMDAC	B-Device
with	O
a	O
256-entry	O
24-bit	O
color	O
look	O
up	O
table	O
,	O
which	O
selects	O
256	O
colors	O
for	O
display	O
out	O
of	O
a	O
palette	O
of	O
16,777,216	O
.	O
</s>
<s>
The	O
frame	B-Algorithm
buffer	I-Algorithm
is	O
treated	O
as	O
part	O
of	O
the	O
memory	O
subsystem	O
.	O
</s>
<s>
The	O
I/O	O
subsystem	O
provides	O
the	O
system	O
with	O
an	O
8-bit	O
single-ended	O
SCSI	O
bus	O
,	O
10	O
Mbit/s	O
Ethernet	O
,	O
serial	B-Protocol
line	I-Protocol
,	O
the	O
Serial	O
Desktop	O
Bus	O
and	O
analog	O
audio	O
.	O
</s>
<s>
Ethernet	O
is	O
provided	O
by	O
an	O
AMD	O
Am7990	O
LANCE	O
(	O
Local	O
Area	O
Network	O
Controller	O
for	O
Ethernet	O
)	O
and	O
an	O
AMD	O
Am7992	O
SIA	O
(	O
Serial	B-Protocol
Interface	I-Protocol
Adapter	I-Protocol
)	O
that	O
implements	O
the	O
AUI	B-Protocol
interface	I-Protocol
.	O
</s>
<s>
A	O
single	O
serial	B-Protocol
port	I-Protocol
capable	O
of	O
50	O
to	O
19,200	O
baud	O
with	O
full	O
modem	O
control	O
capability	O
is	O
provided	O
by	O
a	O
Zilog	O
Z85C30	O
SCC	O
(	O
Serial	O
Communications	O
Controller	O
)	O
.	O
</s>
<s>
The	O
ASIC	O
interfaces	O
the	O
subsystem	O
to	O
the	O
TURBOchannel	B-Device
interconnect	O
.	O
</s>
<s>
ModelProcessorMHzIntroducedDiscontinuedModel	O
120R3000A	O
,	O
R3010	B-Device
chipset20DECstation	O
5000/100	O
Series	O
Workstations	B-Device
,	O
Digital	O
Equipment	O
Corporation	O
?	O
</s>
<s>
?	O
Model	O
125R3000A	O
,	O
R3010	B-Device
chipset25	O
?	O
</s>
<s>
?	O
Model	O
133R3000A	O
,	O
R3010	B-Device
chipset33	O
?	O
</s>
<s>
The	O
DECstation	B-Device
5000	O
Model	O
100	O
Series	O
,	O
code	O
named	O
"	O
3MIN	O
"	O
,	O
are	O
mid-range	O
workstations	B-Device
.	O
</s>
<s>
Early	O
models	O
used	O
a	O
chipset	O
consisting	O
of	O
a	O
R3000A	B-Device
CPU	O
and	O
a	O
R3010	B-Device
CPU	O
on	O
3	O
-	O
by	O
5-inch	O
daughter	O
card	O
that	O
plugs	O
into	O
a	O
connector	O
on	O
the	O
system	O
module	O
.	O
</s>
<s>
The	O
Model	O
150	O
replaces	O
the	O
R3000A	B-Device
and	O
R3010	B-Device
with	O
a	O
single	O
R4000	B-General_Concept
with	O
an	O
integrated	O
FPU	O
.	O
</s>
<s>
These	O
systems	O
support	O
16	O
to	O
128	O
MB	O
of	O
memory	O
through	O
16	O
SIMM	B-General_Concept
slots	O
that	O
accept	O
2	O
or	O
8	O
MB	O
SIMMs	B-General_Concept
.	O
</s>
<s>
Only	O
one	O
type	O
of	O
SIMM	B-General_Concept
may	O
be	O
used	O
,	O
2	O
and	O
8	O
MB	O
SIMMs	B-General_Concept
cannot	O
be	O
mixed	O
in	O
the	O
same	O
system	O
.	O
</s>
<s>
The	O
2	O
MB	O
SIMM	B-General_Concept
is	O
identical	O
to	O
the	O
SIMM	B-General_Concept
used	O
in	O
the	O
DECstation	B-Device
2100	O
and	O
3100	O
,	O
allowing	O
upgrades	O
from	O
these	O
older	O
systems	O
to	O
the	O
Model	O
100	O
Series	O
to	O
reuse	O
the	O
old	O
memory	O
.	O
</s>
<s>
Three	O
TURBOchannel	B-Device
option	O
slots	O
are	O
provided	O
.	O
</s>
<s>
The	O
Model	O
100	O
Series	O
introduces	O
the	O
I/O	O
Controller	O
ASIC	O
(	O
later	O
known	O
as	O
the	O
IOCTL	O
ASIC	O
)	O
,	O
which	O
interfaces	O
the	O
two	O
8-bit	O
I/O	O
buses	O
to	O
the	O
12.5MHz	O
TURBOchannel	B-Device
.	O
</s>
<s>
The	O
DECstation	B-Device
200	O
Series	O
are	O
high-end	O
workstations	B-Device
.	O
</s>
<s>
Server	O
configurations	O
of	O
the	O
DECstation	B-Device
500	O
Model	O
200	O
,	O
240	O
and	O
260	O
were	O
known	O
as	O
the	O
DECsystem	B-Device
5000	O
Model	O
200	O
,	O
240	O
and	O
260	O
respectively	O
.	O
</s>
<s>
Alternatively	O
,	O
storage	O
was	O
to	O
be	O
provided	O
by	O
a	O
file	B-Application
server	I-Application
accessed	O
over	O
a	O
network	O
.	O
</s>
<s>
Model	O
and	O
codenameProcessorMHzIntroducedDiscontinuedModel	O
200	O
"	O
3MAX	O
"	O
R3000	B-Device
,	O
R3010	B-Device
chipset253	O
April	O
1990	O
?	O
Model	O
240	O
"	O
3MAX+	O
"	O
R3400Worksystems	O
Base	O
Product	O
Marketing	O
:	O
"	O
DECstation	B-Device
5000	O
Model	O
240	O
Workstation	B-Device
Technical	O
Overview	O
"	O
,	O
Version	O
1.0	O
,	O
December	O
1991	O
,	O
Digital	O
Equipment	O
Corporation40	O
?	O
No	O
earlier	O
than	O
September	O
1994Model	O
260	O
"	O
3MAX+	O
"	O
R4400DECstation/DECsystem	O
5000	O
Model	O
200	O
Series	O
Maintenance	O
Guide	O
,	O
Second	O
Printing	O
,	O
April	O
1993	O
,	O
EK-PM38C-MG-002	O
,	O
Digital	O
Equipment	O
Corporation120	O
?	O
</s>
<s>
The	O
Model	O
200	O
's	O
CPU	O
subsystem	O
is	O
located	O
on	O
the	O
KN02	O
system	O
module	O
and	O
contains	O
a	O
chipset	O
composed	O
of	O
the	O
R3000	B-Device
CPU	O
,	O
R3010	B-Device
FPU	O
and	O
R3220	O
MB	O
(	O
six-stage	O
write/memory	O
buffer	O
)	O
.	O
</s>
<s>
In	O
contrast	O
,	O
the	O
Model	O
240	O
's	O
CPU	O
subsystem	O
is	O
located	O
on	O
a	O
daughter	O
card	O
,	O
the	O
CPU	O
module	O
,	O
and	O
does	O
not	O
use	O
a	O
processor	O
chipset	O
,	O
featuring	O
a	O
single	O
40MHz	O
R3400	B-Device
instead	O
.	O
</s>
<s>
The	O
R3400	B-Device
integrates	O
the	O
R3000A	B-Device
CPU	O
and	O
the	O
R3010	B-Device
FPU	O
in	O
a	O
single	O
die	O
and	O
package	O
.	O
</s>
<s>
The	O
processor	O
's	O
external	O
64	O
KB	O
instruction	O
cache	O
and	O
64	O
KB	O
data	O
cache	O
is	O
connected	O
to	O
the	O
R3400	B-Device
by	O
a	O
40MHz	O
bus	O
that	O
also	O
serves	O
as	O
the	O
datapath	O
to	O
the	O
MB	O
ASIC	O
.	O
</s>
<s>
The	O
Model	O
260	O
's	O
CPU	O
subsystem	O
is	O
also	O
located	O
on	O
a	O
CPU	O
module	O
daughter	O
card	O
,	O
but	O
it	O
features	O
a	O
120MHz	O
(	O
60MHz	O
external	O
)	O
R4000	B-General_Concept
with	O
internal	O
instruction	O
and	O
data	O
caches	O
and	O
an	O
external	O
secondary	O
cache	O
.	O
</s>
<s>
The	O
Model	O
260	O
's	O
CPU	O
subsystem	O
is	O
unique	O
in	O
the	O
Model	O
200	O
Series	O
as	O
it	O
contains	O
the	O
boot	O
ROM	O
firmware	B-Application
,	O
unlike	O
the	O
other	O
members	O
,	O
which	O
have	O
their	O
boot	O
ROM	O
located	O
in	O
the	O
system	O
module	O
.	O
</s>
<s>
This	O
difference	O
is	O
due	O
to	O
the	O
R4000	B-General_Concept
requiring	O
different	O
firmware	B-Application
that	O
could	O
not	O
be	O
replaced	O
when	O
upgrading	O
a	O
Model	O
240	O
to	O
a	O
Model	O
260	O
.	O
</s>
<s>
The	O
Model	O
200	O
Series	O
has	O
15	O
SIMM	B-General_Concept
slots	O
located	O
on	O
the	O
system	O
module	O
that	O
can	O
hold	O
8	O
to	O
480	O
MB	O
of	O
memory	O
.	O
</s>
<s>
Proprietary	O
128-pin	O
memory	O
array	O
modules	O
(	O
SIMMs	B-General_Concept
)	O
with	O
capacities	O
of	O
8	O
MB	O
(	O
39	O
1	O
Mbit	O
DRAM	O
chips	O
)	O
or	O
32	O
MB	O
(	O
39	O
4	O
Mbit	O
DRAM	O
chips	O
)	O
are	O
used	O
.	O
</s>
<s>
All	O
SIMMs	B-General_Concept
installed	O
in	O
a	O
system	O
must	O
be	O
of	O
the	O
same	O
size	O
.	O
</s>
<s>
If	O
8	O
MB	O
SIMMs	B-General_Concept
are	O
used	O
,	O
the	O
system	O
may	O
contain	O
8	O
to	O
120	O
MB	O
of	O
memory	O
.	O
</s>
<s>
If	O
32	O
MB	O
SIMMs	B-General_Concept
are	O
used	O
,	O
the	O
system	O
may	O
contain	O
32	O
to	O
480	O
MB	O
of	O
memory	O
.	O
</s>
<s>
The	O
memory	O
subsystem	O
operates	O
at	O
25MHz	O
and	O
is	O
32	O
bits	O
wide	O
to	O
match	O
the	O
native	O
word	O
length	O
of	O
the	O
R3000	B-Device
.	O
</s>
<s>
The	O
SIMMs	B-General_Concept
are	O
two-way	O
interleaved	O
using	O
the	O
low-order	O
method	O
,	O
where	O
even	O
and	O
odd	O
memory	O
addresses	O
are	O
treated	O
as	O
separate	O
banks	O
of	O
memory	O
.	O
</s>
<s>
An	O
optional	O
1	O
MB	O
NVRAM	B-General_Concept
module	O
that	O
provides	O
a	O
disk	B-Device
cache	I-Device
to	O
improve	O
performance	O
can	O
be	O
installed	O
in	O
one	O
of	O
the	O
SIMM	B-General_Concept
slots	O
(	O
slot	O
14	O
,	O
the	O
SIMM	B-General_Concept
slot	O
closest	O
to	O
the	O
front	O
edge	O
of	O
the	O
system	O
module	O
)	O
.	O
</s>
<s>
The	O
MS	O
(	O
Memory	O
Strobe	O
)	O
ASIC	O
provides	O
15	O
sets	O
of	O
memory	O
control	O
lines	O
and	O
routes	O
memory	O
control	O
signals	O
from	O
the	O
MT	O
ASIC	O
to	O
the	O
destination	O
SIMM	B-General_Concept
.	O
</s>
<s>
The	O
Model	O
200	O
Series	O
uses	O
the	O
TURBOchannel	B-Device
Interconnect	O
for	O
expansion	O
and	O
all	O
models	O
have	O
three	O
TURBOchannel	B-Device
option	O
slots	O
.	O
</s>
<s>
The	O
Model	O
200	O
provides	O
4	O
MB	O
of	O
physical	O
address	O
space	O
for	O
each	O
TURBOchannel	B-Device
option	O
,	O
while	O
the	O
Model	O
240	O
and	O
260	O
provides	O
8	O
MB	O
.	O
</s>
<s>
TURBOchannel	B-Device
in	O
the	O
Model	O
240	O
and	O
260	O
is	O
clocked	O
at	O
25MHz	O
.	O
</s>
<s>
In	O
the	O
Model	O
240	O
and	O
260	O
,	O
the	O
MT	O
ASIC	O
implements	O
TURBOchannel	B-Device
and	O
serves	O
as	O
the	O
controller	O
.	O
</s>
<s>
In	O
the	O
Model	O
200	O
,	O
Ethernet	O
and	O
SCSI	O
capabilities	O
are	O
provided	O
by	O
two	O
integrated	O
TURBOchannel	B-Device
option	O
modules	O
,	O
PMAD-AA	O
for	O
Ethernet	O
and	O
PMAZ-AA	O
for	O
SCSI	O
.	O
</s>
<s>
The	O
interface	O
is	O
implemented	O
by	O
an	O
AMD	O
7992	O
SIA	O
(	O
Serial	B-Protocol
Interface	I-Protocol
Adapter	I-Protocol
)	O
and	O
a	O
BNC	O
ThinWire	O
connector	O
.	O
</s>
<s>
Four	O
serial	B-Protocol
lines	I-Protocol
are	O
also	O
provided	O
for	O
the	O
keyboard	O
,	O
mouse	O
,	O
communications	O
port	O
and	O
printer	O
.	O
</s>
<s>
A	O
Dallas	O
Semiconductor	O
DS1287	O
real	O
time	O
clock	O
with	O
50	O
bytes	O
of	O
NVRAM	B-General_Concept
is	O
also	O
featured	O
,	O
as	O
is	O
a	O
256	O
KB	O
system	O
boot-strap	O
and	O
diagnostic	O
ROM	O
in	O
a	O
socket	O
.	O
</s>
<s>
In	O
contrast	O
,	O
the	O
Model	O
240	O
's	O
and	O
260	O
's	O
I/O	O
subsystem	O
is	O
based	O
around	O
an	O
I/O	O
Controller	O
ASIC	O
that	O
serves	O
as	O
a	O
bridge	O
between	O
TURBOchannel	B-Device
and	O
the	O
two	O
I/O	O
buses	O
it	O
implements	O
.	O
</s>
<s>
The	O
Model	O
240	O
's	O
I/O	O
subsystem	O
would	O
later	O
be	O
used	O
in	O
the	O
DEC	B-Device
3000	I-Device
AXP	I-Device
in	O
a	O
modified	O
form	O
.	O
</s>
<s>
DECstation	B-Device
systems	O
with	O
TURBOchannel	B-Device
slots	O
could	O
use	O
TURBOchannel-based	O
framebuffers	B-Algorithm
,	O
2D	O
graphics	O
accelerators	O
and	O
3D	O
graphics	O
accelerators	O
.	O
</s>
<s>
CX	O
"	O
Color	O
Frame-Buffer	B-Algorithm
Graphics	O
Module	O
"	O
,	O
model	O
PMAG-BA	O
.	O
</s>
<s>
HX	O
"	O
Smart	O
Frame-Buffer	B-Algorithm
Graphics	O
Module	O
"	O
,	O
models	O
PMAGB-BA/BC/BE	O
.	O
</s>
<s>
The	O
HX	O
is	O
a	O
framebuffer	B-Algorithm
with	O
a	O
custom	O
ASIC	O
with	O
limited	O
,	O
but	O
very	O
fast	O
,	O
2D	O
acceleration	O
capabilities	O
.	O
</s>
<s>
MX	O
"	O
Monochrome	O
Frame-Buffer	B-Algorithm
Graphics	O
Module	O
"	O
,	O
model	O
PMAG-AA	O
.	O
</s>
<s>
TX	O
"	O
True	O
Color	O
Frame-Buffer	B-Algorithm
Graphics	O
Module	O
"	O
,	O
models	O
PMAG-JA	O
,	O
PMAGB-JA	O
.	O
</s>
<s>
The	O
DMA	O
engine	O
interfaces	O
the	O
pipeline	O
to	O
the	O
system	O
via	O
TURBOchannel	B-Device
,	O
receiving	O
packets	O
from	O
the	O
CPU	O
and	O
sending	O
them	O
to	O
the	O
geometry	O
engine	O
.	O
</s>
<s>
The	O
geometry	O
engine	O
consists	O
of	O
an	O
amount	O
of	O
SRAM	O
and	O
an	O
Intel	B-General_Concept
i860	I-General_Concept
.	O
</s>
<s>
Once	O
the	O
data	O
has	O
been	O
processed	O
by	O
the	O
STAMP	O
ASICs	O
,	O
the	O
result	O
,	O
which	O
consists	O
of	O
RGB	O
data	O
,	O
is	O
written	O
into	O
the	O
framebuffer	B-Algorithm
built	O
from	O
VSIMMs	O
(	O
a	O
SIMM	B-General_Concept
with	O
VRAMs	O
)	O
that	O
are	O
located	O
on	O
the	O
graphics	O
accelerator	O
option	O
module	O
to	O
be	O
displayed	O
.	O
</s>
<s>
The	O
PXG	O
and	O
PXG+	O
are	O
double-width	O
TURBOchannel	B-Device
option	O
modules	O
and	O
the	O
PXG	O
Turbo	O
and	O
PXG	O
Turbo+	O
are	O
triple-width	O
TURBOchannel	B-Device
option	O
modules	O
.	O
</s>
<s>
Depending	O
on	O
the	O
model	O
of	O
DECstation	B-Device
,	O
some	O
systems	O
were	O
capable	O
of	O
performing	O
video	B-Application
conferencing	I-Application
,	O
high-quality	O
audio	O
output	O
and	O
video	O
input	O
.	O
</s>
<s>
These	O
were	O
achieved	O
through	O
the	O
use	O
of	O
TURBOchannel	B-Device
option	O
modules	O
and	O
external	O
peripherals	O
.	O
</s>
<s>
Video	O
input	O
was	O
achieved	O
by	O
using	O
the	O
DECvideo	O
(	O
also	O
known	O
as	O
the	O
PIP	O
(	O
Picture-in-Picture	O
)	O
live-video-in	O
)	O
option	O
,	O
a	O
daughterboard	O
that	O
plugs	O
into	O
the	O
TX	O
framebuffer	B-Algorithm
to	O
provide	O
NTSC	O
,	O
PAL	B-Language
and	O
SECAM	O
input	O
.	O
</s>
<s>
When	O
this	O
option	O
was	O
used	O
in	O
conjunction	O
with	O
a	O
video	O
camera	O
,	O
a	O
microphone	O
and	O
the	O
required	O
software	O
,	O
the	O
DECstation	B-Device
can	O
be	O
used	O
for	O
video	B-Application
conferencing	I-Application
.	O
</s>
<s>
Audio	O
capabilities	O
were	O
provided	O
by	O
the	O
DECaudio	O
TURBOchannel	B-Device
option	O
module	O
,	O
which	O
contained	O
two	O
AMD	O
79C30A	O
DSC	O
(	O
Digital	O
Subscriber	O
Controller	O
)	O
devices	O
and	O
a	O
Motorola	B-Architecture
56001	O
DSP	B-Architecture
.	O
</s>
<s>
The	O
two	O
AMD	O
79C30A	O
DSCs	O
were	O
used	O
for	O
voice-quality	O
audio	O
input	O
and	O
output	O
,	O
while	O
the	O
Motorola	B-Architecture
56001	O
was	O
used	O
for	O
high-quality	O
audio	O
.	O
</s>
<s>
The	O
DSP	B-Architecture
was	O
initially	O
not	O
used	O
,	O
due	O
to	O
the	O
firmware	B-Application
being	O
incomplete	O
,	O
although	O
the	O
capability	O
was	O
provided	O
later	O
in	O
an	O
update	O
.	O
</s>
<s>
Confusingly	O
,	O
simultaneous	O
with	O
the	O
launch	O
of	O
the	O
DECstation	B-Device
workstation	B-Device
line	O
,	O
Digital	O
also	O
announced	O
a	O
range	O
of	O
DECstation-branded	O
PC	O
compatibles	O
with	O
Intel	B-Operating_System
x86	I-Operating_System
processors	O
that	O
ran	O
MS-DOS	B-Application
.	O
</s>
<s>
These	O
were	O
identified	O
by	O
three-digit	O
model	O
numbers	O
;	O
the	O
DECstation	B-Device
2xx	O
,	O
3xx	O
and	O
4xx	O
series	O
using	O
the	O
Intel	B-General_Concept
80286	I-General_Concept
,	O
80386	B-General_Concept
and	O
80486	B-General_Concept
processors	O
respectively	O
.	O
</s>
<s>
At	O
the	O
time	O
of	O
introduction	O
,	O
Digital	O
offered	O
a	O
trade-in	O
program	O
for	O
owners	O
of	O
its	O
earlier	O
x86	B-Operating_System
,	O
but	O
PC	O
incompatible	O
,	O
computer	O
,	O
the	O
Rainbow	B-Device
100	I-Device
.	O
</s>
<s>
Systems	O
based	O
on	O
the	O
80286	B-General_Concept
are	O
:	O
</s>
<s>
Systems	O
based	O
on	O
the	O
80386	B-General_Concept
are	O
:	O
</s>
<s>
Systems	O
based	O
on	O
the	O
80486	B-General_Concept
are	O
:	O
</s>
