<s>
Lisp	B-Operating_System
machines	I-Operating_System
are	O
general-purpose	O
computers	O
designed	O
to	O
efficiently	O
run	O
Lisp	B-Language
as	O
their	O
main	O
software	O
and	O
programming	O
language	O
,	O
usually	O
via	O
hardware	O
support	O
.	O
</s>
<s>
They	O
are	O
an	O
example	O
of	O
a	O
high-level	B-Architecture
language	I-Architecture
computer	I-Architecture
architecture	I-Architecture
,	O
and	O
in	O
a	O
sense	O
,	O
they	O
were	O
the	O
first	O
commercial	O
single-user	O
workstations	B-Device
.	O
</s>
<s>
Despite	O
being	O
modest	O
in	O
number	O
(	O
perhaps	O
7,000	O
units	O
total	O
as	O
of	O
1988	O
)	O
Lisp	B-Operating_System
machines	I-Operating_System
commercially	O
pioneered	O
many	O
now-commonplace	O
technologies	O
,	O
including	O
effective	O
garbage	B-General_Concept
collection	I-General_Concept
,	O
laser	O
printing	O
,	O
windowing	B-Application
systems	I-Application
,	O
computer	B-Device
mice	I-Device
,	O
high-resolution	O
bit-mapped	O
raster	B-Algorithm
graphics	I-Algorithm
,	O
computer	O
graphic	O
rendering	O
,	O
and	O
networking	O
innovations	O
such	O
as	O
Chaosnet	B-General_Concept
.	O
</s>
<s>
Several	O
firms	O
built	O
and	O
sold	O
Lisp	B-Operating_System
machines	I-Operating_System
in	O
the	O
1980s	O
:	O
Symbolics	O
(	O
3600	O
,	O
3640	O
,	O
XL1200	O
,	O
MacIvory	O
,	O
and	O
other	O
models	O
)	O
,	O
Lisp	B-Operating_System
Machines	I-Operating_System
Incorporated	O
(	O
LMI	O
Lambda	O
)	O
,	O
Texas	O
Instruments	O
(	O
Explorer	B-Language
,	I-Language
MicroExplorer	I-Language
)	O
,	O
and	O
Xerox	O
(	O
Interlisp-D	B-Language
workstations	B-Device
)	O
.	O
</s>
<s>
The	O
operating	B-General_Concept
systems	I-General_Concept
were	O
written	O
in	O
Lisp	B-Language
Machine	I-Language
Lisp	I-Language
,	O
Interlisp	B-Language
(	O
Xerox	O
)	O
,	O
and	O
later	O
partly	O
in	O
Common	B-Language
Lisp	I-Language
.	O
</s>
<s>
Artificial	B-Application
intelligence	I-Application
(	O
AI	B-Application
)	O
computer	O
programs	O
of	O
the	O
1960s	O
and	O
1970s	O
intrinsically	O
required	O
what	O
was	O
then	O
considered	O
a	O
huge	O
amount	O
of	O
computer	O
power	O
,	O
as	O
measured	O
in	O
processor	O
time	O
and	O
memory	O
space	O
.	O
</s>
<s>
The	O
power	O
requirements	O
of	O
AI	B-Application
research	I-Application
were	O
exacerbated	O
by	O
the	O
Lisp	B-Language
symbolic	O
programming	O
language	O
,	O
when	O
commercial	O
hardware	O
was	O
designed	O
and	O
optimized	O
for	O
assembly	B-Language
-	O
and	O
Fortran-like	O
programming	O
languages	O
.	O
</s>
<s>
As	O
integrated	O
circuit	O
technology	O
shrank	O
the	O
size	O
and	O
cost	O
of	O
computers	O
in	O
the	O
1960s	O
and	O
early	O
1970s	O
,	O
and	O
the	O
memory	O
needs	O
of	O
AI	B-Application
programs	O
began	O
to	O
exceed	O
the	O
address	B-General_Concept
space	I-General_Concept
of	O
the	O
most	O
common	O
research	O
computer	O
,	O
the	O
Digital	O
Equipment	O
Corporation	O
(	O
DEC	O
)	O
PDP-10	B-Device
,	O
researchers	O
considered	O
a	O
new	O
approach	O
:	O
a	O
computer	O
designed	O
specifically	O
to	O
develop	O
and	O
run	O
large	O
artificial	B-Application
intelligence	I-Application
programs	I-Application
,	O
and	O
tailored	O
to	O
the	O
semantics	O
of	O
the	O
Lisp	B-Language
language	I-Language
.	O
</s>
<s>
To	O
keep	O
the	O
operating	B-General_Concept
system	I-General_Concept
(	O
relatively	O
)	O
simple	O
,	O
these	O
machines	O
would	O
not	O
be	O
shared	O
,	O
but	O
would	O
be	O
dedicated	O
to	O
single	O
users	O
.	O
</s>
<s>
In	O
1973	O
,	O
Richard	O
Greenblatt	O
and	O
Thomas	O
Knight	O
,	O
programmers	O
at	O
Massachusetts	O
Institute	O
of	O
Technology	O
(	O
MIT	O
)	O
Artificial	B-Application
Intelligence	I-Application
Laboratory	O
(	O
AI	B-Application
Lab	O
)	O
,	O
began	O
what	O
would	O
become	O
the	O
MIT	O
Lisp	B-Operating_System
Machine	I-Operating_System
Project	O
when	O
they	O
first	O
began	O
building	O
a	O
computer	O
hardwired	O
to	O
run	O
certain	O
basic	O
Lisp	B-Language
operations	O
,	O
rather	O
than	O
run	O
them	O
in	O
software	O
,	O
in	O
a	O
24-bit	O
tagged	B-Architecture
architecture	I-Architecture
.	O
</s>
<s>
The	O
machine	O
also	O
did	O
incremental	O
(	O
or	O
Arena	O
)	O
garbage	B-General_Concept
collection	I-General_Concept
.	O
</s>
<s>
More	O
specifically	O
,	O
since	O
Lisp	B-Language
variables	O
are	O
typed	O
at	O
runtime	O
rather	O
than	O
compile	O
time	O
,	O
a	O
simple	O
addition	O
of	O
two	O
variables	O
could	O
take	O
five	O
times	O
as	O
long	O
on	O
conventional	O
hardware	O
,	O
due	O
to	O
test	O
and	O
branch	O
instructions	O
.	O
</s>
<s>
Lisp	B-Operating_System
Machines	I-Operating_System
ran	O
the	O
tests	O
in	O
parallel	O
with	O
the	O
more	O
conventional	O
single	O
instruction	O
additions	O
.	O
</s>
<s>
This	O
simultaneous	O
checking	O
approach	O
was	O
used	O
as	O
well	O
in	O
testing	O
the	O
bounds	O
of	O
arrays	O
when	O
referenced	O
,	O
and	O
other	O
memory	O
management	O
necessities	O
(	O
not	O
merely	O
garbage	B-General_Concept
collection	I-General_Concept
or	O
arrays	O
)	O
.	O
</s>
<s>
Type	O
checking	O
was	O
further	O
improved	O
and	O
automated	O
when	O
the	O
conventional	O
byte	O
word	O
of	O
32-bits	O
was	O
lengthened	O
to	O
36-bits	O
for	O
Symbolics	O
3600-model	O
Lisp	B-Operating_System
machines	I-Operating_System
and	O
eventually	O
to	O
40-bits	O
or	O
more	O
(	O
usually	O
,	O
the	O
excess	O
bits	O
not	O
accounted	O
for	O
by	O
the	O
following	O
were	O
used	O
for	O
error-correcting	B-Error_Name
codes	I-Error_Name
)	O
.	O
</s>
<s>
The	O
first	O
group	O
of	O
extra	O
bits	O
were	O
used	O
to	O
hold	O
type	O
data	O
,	O
making	O
the	O
machine	O
a	O
tagged	B-Architecture
architecture	I-Architecture
,	O
and	O
the	O
remaining	O
bits	O
were	O
used	O
to	O
implement	O
CDR	B-Language
coding	I-Language
(	O
wherein	O
the	O
usual	O
linked	O
list	O
elements	O
are	O
compressed	O
to	O
occupy	O
roughly	O
half	O
the	O
space	O
)	O
,	O
aiding	O
garbage	B-General_Concept
collection	I-General_Concept
by	O
reportedly	O
an	O
order	O
of	O
magnitude	O
.	O
</s>
<s>
A	O
further	O
improvement	O
was	O
two	O
microcode	O
instructions	O
which	O
specifically	O
supported	O
Lisp	B-Language
functions	O
,	O
reducing	O
the	O
cost	O
of	O
calling	O
a	O
function	O
to	O
as	O
little	O
as	O
20	O
clock	O
cycles	O
,	O
in	O
some	O
Symbolics	O
implementations	O
.	O
</s>
<s>
The	O
first	O
machine	O
was	O
called	O
the	O
CONS	B-Protocol
machine	O
(	O
named	O
after	O
the	O
list	O
construction	O
operator	O
cons	B-Protocol
in	O
Lisp	B-Language
)	O
.	O
</s>
<s>
It	O
was	O
subsequently	O
improved	O
into	O
a	O
version	O
called	O
CADR	B-Operating_System
(	O
a	O
pun	O
;	O
in	O
Lisp	B-Language
,	O
the	O
cadr	B-Operating_System
function	O
,	O
which	O
returns	O
the	O
second	O
item	O
of	O
a	O
list	O
,	O
is	O
pronounced	O
or	O
,	O
as	O
some	O
pronounce	O
the	O
word	O
"	O
cadre	O
"	O
)	O
which	O
was	O
based	O
on	O
essentially	O
the	O
same	O
architecture	O
.	O
</s>
<s>
About	O
25	O
of	O
what	O
were	O
essentially	O
prototype	O
CADRs	B-Operating_System
were	O
sold	O
within	O
and	O
without	O
MIT	O
for	O
~	O
$	O
50,000	O
;	O
it	O
quickly	O
became	O
the	O
favorite	O
machine	O
for	O
hacking	O
-	O
many	O
of	O
the	O
most	O
favored	O
software	O
tools	O
were	O
quickly	O
ported	O
to	O
it	O
(	O
e.g.	O
</s>
<s>
Emacs	B-Application
was	O
ported	O
from	O
ITS	B-Application
in	O
1975	O
)	O
.	O
</s>
<s>
It	O
was	O
so	O
well	O
received	O
at	O
an	O
AI	B-Application
conference	O
held	O
at	O
MIT	O
in	O
1978	O
that	O
Defense	O
Advanced	O
Research	O
Projects	O
Agency	O
(	O
DARPA	O
)	O
began	O
funding	O
its	B-Application
development	O
.	O
</s>
<s>
In	O
1979	O
,	O
Russell	O
Noftsker	O
,	O
being	O
convinced	O
that	O
Lisp	B-Operating_System
machines	I-Operating_System
had	O
a	O
bright	O
commercial	O
future	O
due	O
to	O
the	O
strength	O
of	O
the	O
Lisp	B-Language
language	I-Language
and	O
the	O
enabling	O
factor	O
of	O
hardware	O
acceleration	O
,	O
proposed	O
to	O
Greenblatt	O
that	O
they	O
commercialize	O
the	O
technology	O
.	O
</s>
<s>
In	O
a	O
counter-intuitive	O
move	O
for	O
an	O
AI	B-Application
Lab	O
hacker	O
,	O
Greenblatt	O
acquiesced	O
,	O
hoping	O
perhaps	O
that	O
he	O
could	O
recreate	O
the	O
informal	O
and	O
productive	O
atmosphere	O
of	O
the	O
Lab	O
in	O
a	O
real	O
business	O
.	O
</s>
<s>
As	O
the	O
proposed	O
firm	O
could	O
succeed	O
only	O
with	O
the	O
full	O
and	O
undivided	O
assistance	O
of	O
the	O
AI	B-Application
Lab	O
hackers	O
as	O
a	O
group	O
,	O
Noftsker	O
and	O
Greenblatt	O
decided	O
that	O
the	O
fate	O
of	O
the	O
enterprise	O
was	O
up	O
to	O
them	O
,	O
and	O
so	O
the	O
choice	O
should	O
be	O
left	O
to	O
the	O
hackers	O
.	O
</s>
<s>
The	O
hackers	O
sided	O
with	O
Noftsker	O
,	O
believing	O
that	O
a	O
commercial	O
venture	O
fund-backed	O
firm	O
had	O
a	O
better	O
chance	O
of	O
surviving	O
and	O
commercializing	O
Lisp	B-Operating_System
machines	I-Operating_System
than	O
Greenblatt	O
's	O
proposed	O
self-sustaining	O
start-up	O
.	O
</s>
<s>
A	O
consultant	O
from	O
CDC	O
,	O
who	O
was	O
trying	O
to	O
put	O
together	O
a	O
natural	O
language	O
computer	O
application	O
with	O
a	O
group	O
of	O
West-coast	O
programmers	O
,	O
came	O
to	O
Greenblatt	O
,	O
seeking	O
a	O
Lisp	B-Operating_System
machine	I-Operating_System
for	O
his	O
group	O
to	O
work	O
with	O
,	O
about	O
eight	O
months	O
after	O
the	O
disastrous	O
conference	O
with	O
Noftsker	O
.	O
</s>
<s>
Greenblatt	O
had	O
decided	O
to	O
start	O
his	O
own	O
rival	O
Lisp	B-Operating_System
machine	I-Operating_System
firm	O
,	O
but	O
he	O
had	O
done	O
nothing	O
.	O
</s>
<s>
The	O
consultant	O
,	O
Alexander	O
Jacobson	O
,	O
decided	O
that	O
the	O
only	O
way	O
Greenblatt	O
was	O
going	O
to	O
start	O
the	O
firm	O
and	O
build	O
the	O
Lisp	B-Operating_System
machines	I-Operating_System
that	O
Jacobson	O
desperately	O
needed	O
was	O
if	O
Jacobson	O
pushed	O
and	O
otherwise	O
helped	O
Greenblatt	O
launch	O
the	O
firm	O
.	O
</s>
<s>
The	O
newfound	O
firm	O
was	O
named	O
LISP	B-Operating_System
Machine	I-Operating_System
,	O
Inc	O
.	O
(	O
LMI	O
)	O
,	O
and	O
was	O
funded	O
by	O
CDC	O
orders	O
,	O
via	O
Jacobson	O
.	O
</s>
<s>
Symbolics	O
still	O
had	O
the	O
major	O
advantage	O
that	O
while	O
3	O
or	O
4	O
of	O
the	O
AI	B-Application
Lab	O
hackers	O
had	O
gone	O
to	O
work	O
for	O
Greenblatt	O
,	O
a	O
solid	O
14	O
other	O
hackers	O
had	O
signed	O
onto	O
Symbolics	O
.	O
</s>
<s>
Two	O
AI	B-Application
Lab	O
people	O
were	O
not	O
hired	O
by	O
either	O
:	O
Richard	O
Stallman	O
and	O
Marvin	O
Minsky	O
.	O
</s>
<s>
Stallman	O
,	O
however	O
,	O
blamed	O
Symbolics	O
for	O
the	O
decline	O
of	O
the	O
hacker	O
community	O
that	O
had	O
centered	O
around	O
the	O
AI	B-Application
lab	O
.	O
</s>
<s>
Regardless	O
,	O
after	O
a	O
series	O
of	O
internal	O
battles	O
,	O
Symbolics	O
did	O
get	O
off	O
the	O
ground	O
in	O
1980/1981	O
,	O
selling	O
the	O
CADR	B-Operating_System
as	O
the	O
LM-2	O
,	O
while	O
Lisp	B-Operating_System
Machines	I-Operating_System
,	O
Inc	O
.	O
sold	O
it	O
as	O
the	O
LMI-CADR	O
.	O
</s>
<s>
Symbolics	O
did	O
not	O
intend	O
to	O
produce	O
many	O
LM-2s	O
,	O
since	O
the	O
3600	O
family	O
of	O
Lisp	B-Operating_System
machines	I-Operating_System
was	O
supposed	O
to	O
ship	O
quickly	O
,	O
but	O
the	O
3600s	O
were	O
repeatedly	O
delayed	O
,	O
and	O
Symbolics	O
ended	O
up	O
producing	O
~	O
100	O
LM-2s	O
,	O
each	O
of	O
which	O
sold	O
for	O
$	O
70,000	O
.	O
</s>
<s>
Both	O
firms	O
developed	O
second-generation	O
products	O
based	O
on	O
the	O
CADR	B-Operating_System
:	O
the	O
Symbolics	O
3600	O
and	O
the	O
LMI-LAMBDA	O
(	O
of	O
which	O
LMI	O
managed	O
to	O
sell	O
~	O
200	O
)	O
.	O
</s>
<s>
The	O
3600	O
,	O
which	O
shipped	O
a	O
year	O
late	O
,	O
expanded	O
on	O
the	O
CADR	B-Operating_System
by	O
widening	O
the	O
machine	O
word	O
to	O
36-bits	O
,	O
expanding	O
the	O
address	B-General_Concept
space	I-General_Concept
to	O
28-bits	O
,	O
and	O
adding	O
hardware	O
to	O
accelerate	O
certain	O
common	O
functions	O
that	O
were	O
implemented	O
in	O
microcode	O
on	O
the	O
CADR	B-Operating_System
.	O
</s>
<s>
The	O
LMI-LAMBDA	O
,	O
which	O
came	O
out	O
a	O
year	O
after	O
the	O
3600	O
,	O
in	O
1983	O
,	O
was	O
compatible	O
with	O
the	O
CADR	B-Operating_System
(	O
it	O
could	O
run	O
CADR	B-Operating_System
microcode	O
)	O
,	O
but	O
hardware	O
differences	O
existed	O
.	O
</s>
<s>
Texas	O
Instruments	O
(	O
TI	O
)	O
joined	O
the	O
fray	O
when	O
it	O
licensed	O
the	O
LMI-LAMBDA	O
design	O
and	O
produced	O
its	B-Application
own	O
variant	O
,	O
the	O
TI	B-Language
Explorer	I-Language
.	O
</s>
<s>
Some	O
of	O
the	O
LMI-LAMBDAs	O
and	O
the	O
TI	B-Language
Explorer	I-Language
were	O
dual	O
systems	O
with	O
both	O
a	O
Lisp	B-Language
and	O
a	O
Unix	B-Application
processor	O
.	O
</s>
<s>
TI	O
also	O
developed	O
a	O
32-bit	O
microprocessor	B-Architecture
version	O
of	O
its	B-Application
Lisp	B-Language
CPU	O
for	O
the	O
TI	B-Language
Explorer	I-Language
.	O
</s>
<s>
This	O
Lisp	B-Language
chip	O
also	O
was	O
used	O
for	O
the	O
MicroExplorer	O
–	O
a	O
NuBus	B-Device
board	O
for	O
the	O
Apple	B-Device
Macintosh	I-Device
II	I-Device
(	O
NuBus	B-Device
was	O
initially	O
developed	O
at	O
MIT	O
for	O
use	O
in	O
Lisp	B-Operating_System
machines	I-Operating_System
)	O
.	O
</s>
<s>
Symbolics	O
continued	O
to	O
develop	O
the	O
3600	O
family	O
and	O
its	B-Application
operating	B-General_Concept
system	I-General_Concept
,	O
Genera	B-Application
,	O
and	O
produced	O
the	O
Ivory	O
,	O
a	O
VLSI	O
implementation	O
of	O
the	O
Symbolics	O
architecture	O
.	O
</s>
<s>
Starting	O
in	O
1987	O
,	O
several	O
machines	O
based	O
on	O
the	O
Ivory	O
processor	O
were	O
developed	O
:	O
boards	O
for	O
Suns	O
and	O
Macs	O
,	O
stand-alone	O
workstations	B-Device
and	O
even	O
embedded	O
systems	O
(	O
I-Machine	O
Custom	O
LSI	O
,	O
32	O
bit	O
address	O
,	O
Symbolics	O
XL-400	O
,	O
UX-400	O
,	O
MacIvory	O
II	O
;	O
in	O
1989	O
available	O
platforms	O
were	O
Symbolics	O
XL-1200	O
,	O
MacIvory	O
III	O
,	O
UX-1200	O
,	O
Zora	O
,	O
NXP1000	O
"	O
pizza	O
box	O
"	O
)	O
.	O
</s>
<s>
Texas	O
Instruments	O
shrank	O
the	O
Explorer	O
into	O
silicon	O
as	O
the	O
MicroExplorer	O
which	O
was	O
offered	O
as	O
a	O
card	O
for	O
the	O
Apple	O
Mac	B-Device
II	I-Device
.	O
</s>
<s>
LMI	O
abandoned	O
the	O
CADR	B-Operating_System
architecture	O
and	O
developed	O
its	B-Application
own	O
K-Machine	O
,	O
but	O
LMI	O
went	O
bankrupt	O
before	O
the	O
machine	O
could	O
be	O
brought	O
to	O
market	O
.	O
</s>
<s>
Before	O
its	B-Application
demise	O
,	O
LMI	O
was	O
working	O
on	O
a	O
distributed	O
system	O
for	O
the	O
LAMBDA	O
using	O
Moby	O
space	O
.	O
</s>
<s>
These	O
machines	O
had	O
hardware	O
support	O
for	O
various	O
primitive	O
Lisp	B-Language
operations	O
(	O
data	O
type	O
testing	O
,	O
CDR	B-Language
coding	I-Language
)	O
and	O
also	O
hardware	O
support	O
for	O
incremental	O
garbage	B-General_Concept
collection	I-General_Concept
.	O
</s>
<s>
They	O
ran	O
large	O
Lisp	B-Language
programs	O
very	O
efficiently	O
.	O
</s>
<s>
The	O
Symbolics	O
machine	O
was	O
competitive	O
against	O
many	O
commercial	O
super	O
minicomputers	B-Architecture
,	O
but	O
was	O
never	O
adapted	O
for	O
conventional	O
purposes	O
.	O
</s>
<s>
The	O
Symbolics	O
Lisp	B-Operating_System
Machines	I-Operating_System
were	O
also	O
sold	O
to	O
some	O
non-AI	O
markets	O
like	O
computer	O
graphics	O
,	O
modeling	O
,	O
and	O
animation	O
.	O
</s>
<s>
The	O
MIT-derived	O
Lisp	B-Operating_System
machines	I-Operating_System
ran	O
a	O
Lisp	B-Language
dialect	O
named	O
Lisp	B-Language
Machine	I-Language
Lisp	I-Language
,	O
descended	O
from	O
MIT	O
's	O
Maclisp	B-Language
.	O
</s>
<s>
The	O
operating	B-General_Concept
systems	I-General_Concept
were	O
written	O
from	O
the	O
ground	O
up	O
in	O
Lisp	B-Language
,	O
often	O
using	O
object-oriented	O
extensions	O
.	O
</s>
<s>
Later	O
,	O
these	O
Lisp	B-Operating_System
machines	I-Operating_System
also	O
supported	O
various	O
versions	O
of	O
Common	B-Language
Lisp	I-Language
(	O
with	O
Flavors	B-Language
,	O
New	B-Language
Flavors	I-Language
,	O
and	O
Common	B-Application
Lisp	I-Application
Object	I-Application
System	I-Application
(	O
CLOS	B-Application
)	O
)	O
.	O
</s>
<s>
Bolt	O
,	O
Beranek	O
and	O
Newman	O
(	O
BBN	O
)	O
developed	O
its	B-Application
own	O
Lisp	B-Operating_System
machine	I-Operating_System
,	O
named	O
Jericho	O
,	O
which	O
ran	O
a	O
version	O
of	O
Interlisp	B-Language
.	O
</s>
<s>
Frustrated	O
,	O
the	O
whole	O
AI	B-Application
group	O
resigned	O
,	O
and	O
were	O
hired	O
mostly	O
by	O
Xerox	O
.	O
</s>
<s>
So	O
,	O
Xerox	O
Palo	O
Alto	O
Research	O
Center	O
had	O
,	O
simultaneously	O
with	O
Greenblatt	O
's	O
own	O
development	O
at	O
MIT	O
,	O
developed	O
their	O
own	O
Lisp	B-Operating_System
machines	I-Operating_System
which	O
were	O
designed	O
to	O
run	O
InterLisp	B-Language
(	O
and	O
later	O
Common	B-Language
Lisp	I-Language
)	O
.	O
</s>
<s>
The	O
same	O
hardware	O
was	O
used	O
with	O
different	O
software	O
also	O
as	O
Smalltalk	B-Application
machines	O
and	O
as	O
the	O
Xerox	B-Operating_System
Star	I-Operating_System
office	O
system	O
.	O
</s>
<s>
These	O
included	O
the	O
Xerox	O
1100	O
,	O
Dolphin	O
(	O
1979	O
)	O
;	O
the	O
Xerox	O
1132	O
,	O
Dorado	O
;	O
the	O
Xerox	O
1108	O
,	O
Dandelion	O
(	O
1981	O
)	O
;	O
the	O
Xerox	O
1109	O
,	O
Dandetiger	O
;	O
and	O
the	O
Xerox	B-Device
1186/6085	I-Device
,	O
Daybreak	O
.	O
</s>
<s>
The	O
operating	B-General_Concept
system	I-General_Concept
of	O
the	O
Xerox	O
Lisp	B-Operating_System
machines	I-Operating_System
has	O
also	O
been	O
ported	O
to	O
a	O
virtual	O
machine	O
and	O
is	O
available	O
for	O
several	O
platforms	O
as	O
a	O
product	O
named	O
Medley	O
.	O
</s>
<s>
The	O
Xerox	O
machine	O
was	O
well	O
known	O
for	O
its	B-Application
advanced	O
development	O
environment	O
(	O
InterLisp-D	B-Language
)	O
,	O
the	O
ROOMS	O
window	O
manager	O
,	O
for	O
its	B-Application
early	O
graphical	O
user	O
interface	O
and	O
for	O
novel	O
applications	O
like	O
NoteCards	B-Application
(	O
one	O
of	O
the	O
first	O
hypertext	O
applications	O
)	O
.	O
</s>
<s>
Xerox	O
also	O
worked	O
on	O
a	O
Lisp	B-Operating_System
machine	I-Operating_System
based	O
on	O
reduced	B-Architecture
instruction	I-Architecture
set	I-Architecture
computing	I-Architecture
(	O
RISC	B-Architecture
)	O
,	O
using	O
the	O
'	O
Xerox	O
Common	B-Language
Lisp	I-Language
Processor	O
 '	O
and	O
planned	O
to	O
bring	O
it	O
to	O
market	O
by	O
1987	O
,	O
which	O
did	O
not	O
occur	O
.	O
</s>
<s>
In	O
the	O
mid-1980s	O
,	O
Integrated	O
Inference	O
Machines	O
(	O
IIM	O
)	O
built	O
prototypes	O
of	O
Lisp	B-Operating_System
machines	I-Operating_System
named	O
Inferstar	O
.	O
</s>
<s>
In	O
1984	O
–	O
85	O
a	O
UK	O
firm	O
,	O
Racal-Norsk	O
,	O
a	O
joint	O
subsidiary	O
of	O
Racal	O
and	O
Norsk	O
Data	O
,	O
attempted	O
to	O
repurpose	O
Norsk	O
Data	O
's	O
ND-500	B-Device
supermini	O
as	O
a	O
microcoded	O
Lisp	B-Operating_System
machine	I-Operating_System
,	O
running	O
CADR	B-Operating_System
software	O
:	O
the	O
Knowledge	O
Processing	O
System	O
(	O
KPS	O
)	O
.	O
</s>
<s>
There	O
were	O
several	O
attempts	O
by	O
Japanese	O
manufacturers	O
to	O
enter	O
the	O
Lisp	B-Operating_System
machine	I-Operating_System
market	O
:	O
the	O
Fujitsu	O
Facom-alpha	O
mainframe	O
co-processor	O
,	O
NTT	O
's	O
Elis	O
,	O
Toshiba	O
's	O
AI	B-Application
processor	O
(	O
AIP	O
)	O
and	O
NEC	O
's	O
LIME	O
.	O
</s>
<s>
In	O
France	O
,	O
two	O
Lisp	B-Operating_System
Machine	I-Operating_System
projects	O
arose	O
:	O
M3L	O
at	O
Toulouse	O
Paul	O
Sabatier	O
University	O
and	O
later	O
MAIA	O
.	O
</s>
<s>
In	O
Germany	O
Siemens	O
designed	O
the	O
RISC-based	B-Architecture
Lisp	B-Language
co-processor	O
COLIBRI	O
.	O
</s>
<s>
With	O
the	O
onset	O
of	O
the	O
AI	B-Application
winter	O
and	O
the	O
early	O
beginnings	O
of	O
the	O
microcomputer	O
revolution	O
,	O
which	O
would	O
sweep	O
away	O
the	O
minicomputer	B-Architecture
and	O
workstation	B-Device
makers	O
,	O
cheaper	O
desktop	O
PCs	O
soon	O
could	O
run	O
Lisp	B-Language
programs	O
even	O
faster	O
than	O
Lisp	B-Operating_System
machines	I-Operating_System
,	O
with	O
no	O
use	O
of	O
special	O
purpose	O
hardware	O
.	O
</s>
<s>
Their	O
high	O
profit	O
margin	O
hardware	O
business	O
eliminated	O
,	O
most	O
Lisp	B-Operating_System
machine	I-Operating_System
makers	O
had	O
gone	O
out	O
of	O
business	O
by	O
the	O
early	O
90s	O
,	O
leaving	O
only	O
software	O
based	O
firms	O
like	O
Lucid	O
Inc	O
.	O
or	O
hardware	O
makers	O
who	O
had	O
switched	O
to	O
software	O
and	O
services	O
to	O
avoid	O
the	O
crash	O
.	O
</s>
<s>
,	O
besides	O
Xerox	O
and	O
TI	O
,	O
Symbolics	O
is	O
the	O
only	O
Lisp	B-Operating_System
machine	I-Operating_System
firm	O
still	O
operating	O
,	O
selling	O
the	O
Open	B-Application
Genera	I-Application
Lisp	B-Operating_System
machine	I-Operating_System
software	O
environment	O
and	O
the	O
Macsyma	B-Language
computer	O
algebra	O
system	O
.	O
</s>
<s>
Several	O
attempts	O
to	O
write	O
open-source	O
emulators	O
for	O
various	O
Lisp	B-Operating_System
Machines	I-Operating_System
have	O
been	O
made	O
:	O
CADR	B-Operating_System
Emulation	O
,	O
Symbolics	O
L	O
Lisp	B-Operating_System
Machine	I-Operating_System
Emulation	O
,	O
the	O
E3	O
Project	O
(	O
TI	B-Language
Explorer	I-Language
II	O
Emulation	O
)	O
,	O
Meroko	O
(	O
TI	B-Language
Explorer	I-Language
I	O
)	O
,	O
and	O
Nevermore	O
(	O
TI	B-Language
Explorer	I-Language
I	O
)	O
.	O
</s>
<s>
On	O
3	O
October	O
2005	O
,	O
the	O
MIT	O
released	O
the	O
CADR	B-Operating_System
Lisp	B-Operating_System
Machine	I-Operating_System
source	O
code	O
as	O
open	O
source	O
.	O
</s>
<s>
In	O
September	O
2014	O
,	O
Alexander	O
Burger	O
,	O
developer	O
of	O
PicoLisp	B-Language
,	O
announced	O
PilMCU	O
,	O
an	O
implementation	O
of	O
PicoLisp	B-Language
in	O
hardware	O
.	O
</s>
<s>
The	O
Bitsavers	O
 '	O
PDF	O
Document	O
Archive	O
has	O
PDF	O
versions	O
of	O
the	O
extensive	O
documentation	O
for	O
the	O
Symbolics	O
Lisp	B-Operating_System
Machines	I-Operating_System
,	O
the	O
TI	B-Language
Explorer	I-Language
and	O
MicroExplorer	O
Lisp	B-Operating_System
Machines	I-Operating_System
and	O
the	O
Xerox	O
Interlisp-D	B-Language
Lisp	B-Operating_System
Machines	I-Operating_System
.	O
</s>
<s>
Domains	O
using	O
the	O
Lisp	B-Operating_System
machines	I-Operating_System
were	O
mostly	O
in	O
the	O
wide	O
field	O
of	O
artificial	B-Application
intelligence	I-Application
applications	O
,	O
but	O
also	O
in	O
computer	O
graphics	O
,	O
medical	O
image	O
processing	O
,	O
and	O
many	O
others	O
.	O
</s>
<s>
Initially	O
the	O
Lisp	B-Operating_System
machines	I-Operating_System
were	O
designed	O
as	O
personal	B-Device
workstations	I-Device
for	O
software	O
development	O
in	O
Lisp	B-Language
.	O
</s>
<s>
The	O
processor	O
did	O
not	O
run	O
Lisp	B-Language
directly	O
,	O
but	O
was	O
a	O
stack	B-Application
machine	I-Application
with	O
instructions	O
optimized	O
for	O
compiled	O
Lisp	B-Language
.	O
</s>
<s>
The	O
early	O
Lisp	B-Operating_System
machines	I-Operating_System
used	O
microcode	O
to	O
provide	O
the	O
instruction	O
set	O
.	O
</s>
<s>
The	O
result	O
was	O
a	O
very	O
compact	O
compiled	O
representation	O
of	O
Lisp	B-Language
code	O
.	O
</s>
<s>
The	O
disassembled	O
machine	O
code	O
for	O
above	O
function	O
(	O
for	O
the	O
Ivory	O
microprocessor	B-Architecture
from	O
Symbolics	O
)	O
:	O
</s>
<s>
The	O
operating	B-General_Concept
system	I-General_Concept
used	O
virtual	B-Architecture
memory	I-Architecture
to	O
provide	O
a	O
large	O
address	B-General_Concept
space	I-General_Concept
.	O
</s>
<s>
Memory	O
management	O
was	O
done	O
with	O
garbage	B-General_Concept
collection	I-General_Concept
.	O
</s>
<s>
All	O
code	O
shared	O
a	O
single	O
address	B-General_Concept
space	I-General_Concept
.	O
</s>
<s>
All	O
processes	O
ran	O
in	O
the	O
one	O
address	B-General_Concept
space	I-General_Concept
.	O
</s>
<s>
All	O
operating	B-General_Concept
system	I-General_Concept
software	O
was	O
written	O
in	O
Lisp	B-Language
.	O
</s>
<s>
Xerox	O
used	O
Interlisp	B-Language
.	O
</s>
<s>
Symbolics	O
,	O
LMI	O
,	O
and	O
TI	O
used	O
Lisp	B-Language
Machine	I-Language
Lisp	I-Language
(	O
descendant	O
of	O
MacLisp	B-Language
)	O
.	O
</s>
<s>
With	O
the	O
appearance	O
of	O
Common	B-Language
Lisp	I-Language
,	O
Common	B-Language
Lisp	I-Language
was	O
supported	O
on	O
the	O
Lisp	B-Operating_System
Machines	I-Operating_System
and	O
some	O
system	O
software	O
was	O
ported	O
to	O
Common	B-Language
Lisp	I-Language
or	O
later	O
written	O
in	O
Common	B-Language
Lisp	I-Language
.	O
</s>
<s>
Some	O
later	O
Lisp	B-Operating_System
machines	I-Operating_System
(	O
like	O
the	O
TI	O
MicroExplorer	O
,	O
the	O
Symbolics	O
MacIvory	O
or	O
the	O
Symbolics	O
UX400/1200	O
)	O
were	O
no	O
longer	O
complete	O
workstations	B-Device
,	O
but	O
boards	O
designed	O
to	O
be	O
embedded	O
in	O
host	O
computers	O
:	O
Apple	B-Device
Macintosh	I-Device
II	I-Device
and	O
Sun-3	B-Device
or	O
Sun-4	B-Device
.	O
</s>
<s>
Some	O
Lisp	B-Operating_System
machines	I-Operating_System
,	O
such	O
as	O
the	O
Symbolics	O
XL1200	O
,	O
had	O
extensive	O
graphics	O
abilities	O
using	O
special	O
graphics	O
boards	O
.	O
</s>
