<s>
The	O
Xerox	B-Device
Alto	I-Device
is	O
a	O
computer	O
designed	O
from	O
its	O
inception	O
to	O
support	O
an	O
operating	B-General_Concept
system	I-General_Concept
based	O
on	O
a	O
graphical	B-Application
user	I-Application
interface	I-Application
(	O
GUI	B-Application
)	O
,	O
later	O
using	O
the	O
desktop	B-Application
metaphor	I-Application
.	O
</s>
<s>
The	O
first	O
machines	O
were	O
introduced	O
on	O
1	O
March	O
1973	O
,	O
a	O
decade	O
before	O
mass-market	O
GUI	B-Application
machines	O
became	O
available	O
.	O
</s>
<s>
The	O
Alto	B-Device
is	O
contained	O
in	O
a	O
relatively	O
small	O
cabinet	O
and	O
uses	O
a	O
custom	O
central	B-General_Concept
processing	I-General_Concept
unit	I-General_Concept
(	O
CPU	O
)	O
built	O
from	O
multiple	O
SSI	O
and	O
MSI	O
integrated	O
circuits	O
.	O
</s>
<s>
Each	O
machine	O
cost	O
tens	O
of	O
thousands	O
of	O
dollars	O
despite	O
its	O
status	O
as	O
a	O
personal	B-Device
computer	I-Device
.	O
</s>
<s>
The	O
Alto	B-Device
became	O
well	O
known	O
in	O
Silicon	O
Valley	O
and	O
its	O
GUI	B-Application
was	O
increasingly	O
seen	O
as	O
the	O
future	O
of	O
computing	O
.	O
</s>
<s>
After	O
two	O
visits	O
to	O
see	O
the	O
Alto	B-Device
,	O
Apple	O
engineers	O
used	O
the	O
concepts	O
to	O
introduce	O
the	O
Apple	B-Device
Lisa	I-Device
and	O
Macintosh	B-Device
systems	O
.	O
</s>
<s>
Xerox	O
eventually	O
commercialized	O
a	O
heavily	O
modified	O
version	O
of	O
the	O
Alto	B-Device
concepts	O
as	O
the	O
Xerox	B-Operating_System
Star	I-Operating_System
,	O
first	O
introduced	O
in	O
1981	O
.	O
</s>
<s>
A	O
complete	O
office	O
system	O
including	O
several	O
workstations	B-Device
,	O
storage	O
and	O
a	O
laser	O
printer	O
cost	O
as	O
much	O
as	O
$100	O
,	O
000	O
,	O
and	O
like	O
the	O
Alto	B-Device
,	O
the	O
Star	O
had	O
little	O
direct	O
impact	O
on	O
the	O
market	O
.	O
</s>
<s>
The	O
first	O
computer	O
with	O
a	O
graphical	O
operating	B-General_Concept
system	I-General_Concept
,	O
the	O
Alto	B-Device
built	O
on	O
earlier	O
graphical	B-Application
interface	I-Application
designs	O
.	O
</s>
<s>
Of	O
further	O
influence	O
was	O
the	O
PLATO	B-Operating_System
education	I-Operating_System
system	I-Operating_System
developed	O
at	O
the	O
Computer-based	B-Operating_System
Education	I-Operating_System
Research	I-Operating_System
Laboratory	I-Operating_System
at	O
the	O
University	O
of	O
Illinois	O
.	O
</s>
<s>
The	O
Alto	B-Device
was	O
designed	O
mostly	O
by	O
Charles	O
P	O
.	O
Thacker	O
.	O
</s>
<s>
An	O
initial	O
run	O
of	O
30	O
units	O
was	O
produced	O
by	O
Xerox	O
El	O
Segundo	O
(	O
Special	O
Programs	O
Group	O
)	O
,	O
working	O
with	O
John	O
Ellenby	O
at	O
PARC	O
and	O
Doug	O
Stewart	O
and	O
Abbey	O
Silverstone	O
at	O
El	O
Segundo	O
,	O
who	O
were	O
responsible	O
for	O
re-designing	O
the	O
Alto	B-Device
's	O
electronics	O
.	O
</s>
<s>
Several	O
Xerox	B-Device
Alto	I-Device
chassis	O
are	O
now	O
on	O
display	B-Device
at	O
the	O
Computer	O
History	O
Museum	O
in	O
Mountain	O
View	O
,	O
California	O
,	O
one	O
is	O
on	O
display	B-Device
at	O
the	O
Computer	O
Museum	O
of	O
America	O
in	O
Roswell	O
,	O
Georgia	O
,	O
and	O
several	O
are	O
in	O
private	O
hands	O
.	O
</s>
<s>
Running	O
systems	O
are	O
on	O
display	B-Device
at	O
the	O
System	O
Source	O
Computer	O
Museum	O
in	O
Hunt	O
Valley	O
,	O
Maryland	O
.	O
</s>
<s>
Charles	O
P	O
.	O
Thacker	O
was	O
awarded	O
the	O
2009	O
Turing	O
Award	O
of	O
the	O
Association	O
for	O
Computing	O
Machinery	O
on	O
March	O
9	O
,	O
2010	O
,	O
for	O
his	O
pioneering	O
design	O
and	O
realization	O
of	O
the	O
Alto	B-Device
.	O
</s>
<s>
The	O
2004	O
Charles	O
Stark	O
Draper	O
Prize	O
was	O
awarded	O
to	O
Thacker	O
,	O
Alan	O
C	O
.	O
Kay	O
,	O
Butler	O
Lampson	O
,	O
and	O
Robert	O
W	O
.	O
Taylor	O
for	O
their	O
work	O
on	O
Alto	B-Device
.	O
</s>
<s>
On	O
October	O
21	O
,	O
2014	O
,	O
Xerox	B-Device
Alto	I-Device
's	O
source	O
code	O
and	O
other	O
resources	O
were	O
released	O
from	O
the	O
Computer	O
History	O
Museum	O
.	O
</s>
<s>
The	O
following	O
description	O
is	O
based	O
mostly	O
on	O
the	O
August	O
1976	O
Alto	B-Device
Hardware	O
Manual	O
by	O
Xerox	O
PARC	O
.	O
</s>
<s>
Alto	B-Device
uses	O
a	O
microcoded	B-Device
design	O
,	O
but	O
unlike	O
many	O
computers	O
,	O
the	O
microcode	B-Device
engine	O
is	O
not	O
hidden	O
from	O
the	O
programmer	O
in	O
a	O
layered	O
design	O
.	O
</s>
<s>
The	O
Alto	B-Device
has	O
a	O
bit-slice	B-General_Concept
arithmetic	B-General_Concept
logic	I-General_Concept
unit	I-General_Concept
(	O
ALU	B-General_Concept
)	O
based	O
on	O
the	O
Texas	O
Instruments	O
74181	O
chip	O
,	O
a	O
ROM	O
control	O
store	O
with	O
a	O
writable	O
control	O
store	O
extension	O
and	O
has	O
128	O
(	O
expandable	O
to	O
512	O
)	O
KB	O
of	O
main	O
memory	O
organized	O
in	O
16-bit	O
words	O
.	O
</s>
<s>
Mass	O
storage	O
is	O
provided	O
by	O
a	O
hard	B-Device
disk	I-Device
drive	I-Device
that	O
uses	O
a	O
removable	O
2.5	O
MB	O
one-platter	O
cartridge	O
(	O
Diablo	O
Systems	O
,	O
a	O
company	O
Xerox	O
later	O
bought	O
)	O
similar	O
to	O
those	O
used	O
by	O
the	O
IBM	B-Device
2310	I-Device
.	O
</s>
<s>
The	O
base	O
machine	O
and	O
one	O
disk	O
drive	O
are	O
housed	O
in	O
a	O
cabinet	O
about	O
the	O
size	O
of	O
a	O
small	O
refrigerator	O
;	O
one	O
more	O
disk	O
drive	O
can	O
be	O
added	O
via	O
daisy-chaining	B-Application
.	O
</s>
<s>
Alto	B-Device
both	O
blurred	O
and	O
ignored	O
the	O
lines	O
between	O
functional	O
elements	O
.	O
</s>
<s>
Rather	O
than	O
a	O
distinct	O
central	B-General_Concept
processing	I-General_Concept
unit	I-General_Concept
with	O
a	O
well-defined	O
electrical	O
interface	O
(	O
e.g.	O
,	O
system	B-Architecture
bus	I-Architecture
)	O
to	O
storage	O
and	O
peripherals	O
,	O
the	O
Alto	B-Device
ALU	B-General_Concept
interacts	O
directly	O
with	O
hardware	O
interfaces	O
to	O
memory	O
and	O
peripherals	O
,	O
driven	O
by	O
microinstructions	B-Device
that	O
are	O
output	O
from	O
the	O
control	O
store	O
.	O
</s>
<s>
The	O
microcode	B-Device
machine	O
supports	O
up	O
to	O
16	O
cooperative	B-Operating_System
multitasking	I-Operating_System
tasks	O
,	O
each	O
with	O
fixed	O
priority	O
.	O
</s>
<s>
The	O
emulator	O
task	O
executes	O
the	O
normal	O
instruction	O
set	O
to	O
which	O
most	O
applications	O
are	O
written	O
;	O
that	O
instruction	O
set	O
is	O
similar	O
to	O
,	O
but	O
not	O
the	O
same	O
as	O
,	O
that	O
of	O
a	O
Data	B-Device
General	I-Device
Nova	I-Device
.	O
</s>
<s>
Other	O
tasks	O
serve	O
the	O
display	B-Device
,	O
memory	O
refresh	O
,	O
disk	O
,	O
network	O
,	O
and	O
other	O
I/O	O
functions	O
.	O
</s>
<s>
As	O
an	O
example	O
,	O
the	O
bitmap	O
display	B-Device
controller	O
is	O
little	O
more	O
than	O
a	O
16-bit	O
shift	B-General_Concept
register	I-General_Concept
;	O
microcode	B-Device
moves	O
display	B-Device
refresh	O
data	O
from	O
main	O
memory	O
to	O
the	O
shift	B-General_Concept
register	I-General_Concept
,	O
which	O
serializes	O
it	O
into	O
a	O
display	B-Device
of	O
pixels	O
corresponding	O
to	O
the	O
ones	O
and	O
zeros	O
of	O
the	O
memory	O
data	O
.	O
</s>
<s>
Ethernet	O
is	O
likewise	O
supported	O
by	O
minimal	O
hardware	O
,	O
with	O
a	O
shift	B-General_Concept
register	I-General_Concept
that	O
acts	O
bidirectionally	O
to	O
serialize	O
output	O
words	O
and	O
deserialize	O
input	O
words	O
.	O
</s>
<s>
Its	O
speed	O
was	O
designed	O
to	O
be	O
3	O
Mbit/s	O
because	O
the	O
microcode	B-Device
engine	O
could	O
not	O
go	O
faster	O
and	O
continue	O
to	O
support	O
the	O
video	O
display	B-Device
,	O
disk	O
activity	O
and	O
memory	O
refresh	O
.	O
</s>
<s>
Unlike	O
most	O
minicomputers	B-Architecture
of	O
the	O
era	O
,	O
Alto	B-Device
does	O
not	O
support	O
a	O
serial	B-General_Concept
terminal	I-General_Concept
for	O
user	O
interface	O
.	O
</s>
<s>
Apart	O
from	O
an	O
Ethernet	O
connection	O
,	O
the	O
Alto	B-Device
's	O
only	O
common	O
output	O
device	O
is	O
a	O
bi-level	O
(	O
black	O
and	O
white	O
)	O
cathode-ray	B-Device
tube	I-Device
(	O
CRT	O
)	O
display	B-Device
with	O
a	O
tilt-and-swivel	O
base	O
,	O
mounted	O
in	O
portrait	O
orientation	O
rather	O
than	O
the	O
more	O
common	O
"	O
landscape	O
"	O
orientation	O
.	O
</s>
<s>
Its	O
input	O
devices	O
are	O
a	O
custom	O
detachable	O
keyboard	B-Device
,	O
a	O
three-button	O
mouse	B-Device
,	O
and	O
an	O
optional	O
5-key	O
chorded	B-Device
keyboard	I-Device
(	O
chord	B-Device
keyset	I-Device
)	O
.	O
</s>
<s>
The	O
last	O
two	O
items	O
had	O
been	O
introduced	O
by	O
SRI	O
's	O
On-Line	O
System	O
;	O
while	O
the	O
mouse	B-Device
was	O
an	O
instant	O
success	O
among	O
Alto	B-Device
users	O
,	O
the	O
chord	B-Device
keyset	I-Device
never	O
became	O
popular	O
.	O
</s>
<s>
These	O
were	O
soon	O
replaced	O
with	O
a	O
ball-type	O
mouse	B-Device
,	O
which	O
was	O
invented	O
by	O
Ronald	O
E	O
.	O
Rider	O
and	O
developed	O
by	O
Bill	O
English	O
.	O
</s>
<s>
These	O
were	O
photo-mechanical	O
mice	O
,	O
first	O
using	O
white	O
light	O
,	O
and	O
then	O
infrared	O
(	O
IR	O
)	O
,	O
to	O
count	O
the	O
rotations	O
of	O
wheels	O
inside	O
the	O
mouse	B-Device
.	O
</s>
<s>
Each	O
key	O
on	O
the	O
Alto	B-Device
keyboard	B-Device
is	O
represented	O
as	O
a	O
separate	O
bit	O
in	O
a	O
set	O
of	O
memory	O
locations	O
.	O
</s>
<s>
This	O
trait	O
can	O
be	O
used	O
to	O
alter	O
from	O
where	O
on	O
the	O
disk	O
the	O
Alto	B-Device
boots	O
.	O
</s>
<s>
The	O
keyboard	B-Device
value	O
is	O
used	O
as	O
the	O
sector	O
address	O
on	O
the	O
disk	O
to	O
boot	O
from	O
,	O
and	O
by	O
holding	O
specific	O
keys	O
down	O
while	O
pressing	O
the	O
boot	O
button	O
,	O
different	O
microcode	B-Device
and	O
operating	B-General_Concept
systems	I-General_Concept
can	O
be	O
loaded	O
.	O
</s>
<s>
Several	O
other	O
I/O	O
devices	O
were	O
developed	O
for	O
the	O
Alto	B-Device
,	O
including	O
a	O
TV	O
camera	O
,	O
the	O
Hy-Type	O
daisywheel	O
printer	O
and	O
a	O
parallel	O
port	O
,	O
although	O
these	O
were	O
quite	O
rare	O
.	O
</s>
<s>
The	O
Alto	B-Device
could	O
also	O
control	O
external	O
disk	O
drives	O
to	O
act	O
as	O
a	O
file	O
server	O
.	O
</s>
<s>
Early	O
software	O
for	O
the	O
Alto	B-Device
was	O
written	O
in	O
the	O
programming	O
language	O
BCPL	B-Language
,	O
and	O
later	O
in	O
Mesa	B-Language
,	O
which	O
was	O
not	O
widely	O
used	O
outside	O
PARC	O
but	O
influenced	O
several	O
later	O
languages	O
,	O
such	O
as	O
Modula	B-Language
.	O
</s>
<s>
The	O
Alto	B-Device
used	O
an	O
early	O
version	O
of	O
ASCII	B-Protocol
which	O
lacked	O
the	O
underscore	O
character	O
,	O
instead	O
having	O
the	O
left-arrow	O
character	O
used	O
in	O
ALGOL	B-Language
60	I-Language
and	O
many	O
derivatives	O
for	O
the	O
assignment	O
operator	O
:	O
this	O
peculiarity	O
may	O
have	O
been	O
the	O
source	O
of	O
the	O
CamelCase	O
style	O
for	O
compound	O
identifiers	O
.	O
</s>
<s>
Altos	B-Device
were	O
also	O
microcode-programmable	O
by	O
users	O
.	O
</s>
<s>
The	O
Alto	B-Device
helped	O
popularize	O
the	O
use	O
of	O
raster	B-Algorithm
graphics	I-Algorithm
model	O
for	O
all	O
output	O
,	O
including	O
text	O
and	O
graphics	O
.	O
</s>
<s>
It	O
also	O
introduced	O
the	O
concept	O
of	O
the	O
bit	B-Algorithm
block	I-Algorithm
transfer	I-Algorithm
operation	O
(	O
bit	B-Algorithm
blit	I-Algorithm
,	O
BitBLT	B-Algorithm
)	O
,	O
as	O
the	O
fundamental	O
programming	O
interface	O
to	O
the	O
display	B-Device
.	O
</s>
<s>
Despite	O
its	O
small	O
memory	O
size	O
,	O
many	O
innovative	O
programs	O
were	O
written	O
for	O
the	O
Alto	B-Device
,	O
including	O
:	O
</s>
<s>
the	O
first	O
WYSIWYG	B-Application
typesetting	O
document	O
preparation	O
systems	O
,	O
Bravo	B-Application
and	O
Gypsy	B-Protocol
;	O
</s>
<s>
the	O
Markup	O
bitmap	B-Application
editor	I-Application
(	O
an	O
early	O
paint	B-Application
program	I-Application
)	O
;	O
</s>
<s>
the	O
first	O
WYSIWYG	B-Application
integrated	O
circuit	O
editor	O
based	O
on	O
the	O
work	O
of	O
Lynn	O
Conway	O
,	O
Carver	O
Mead	O
,	O
and	O
the	O
Mead	O
and	O
Conway	O
revolution	O
;	O
</s>
<s>
one	O
of	O
the	O
first	O
network-based	O
multi-person	O
video	O
games	O
(	O
Alto	B-Application
Trek	I-Application
by	O
Gene	O
Ball	O
)	O
.	O
</s>
<s>
The	O
first	O
electronic	O
spreadsheet	O
program	O
,	O
VisiCalc	B-Application
,	O
did	O
not	O
appear	O
until	O
1979	O
.	O
</s>
<s>
Technically	O
,	O
the	O
Alto	B-Device
was	O
a	O
small	O
minicomputer	B-Architecture
,	O
but	O
it	O
could	O
be	O
considered	O
a	O
personal	B-Device
computer	I-Device
in	O
the	O
sense	O
that	O
it	O
was	O
used	O
by	O
one	O
person	O
sitting	O
at	O
a	O
desk	O
,	O
in	O
contrast	O
with	O
the	O
mainframe	B-Architecture
computers	I-Architecture
and	O
other	O
minicomputers	B-Architecture
of	O
the	O
era	O
.	O
</s>
<s>
It	O
was	O
arguably	O
"	O
the	O
first	O
personal	B-Device
computer	I-Device
"	O
,	O
although	O
this	O
title	O
is	O
disputed	O
by	O
others	O
.	O
</s>
<s>
More	O
significantly	O
(	O
and	O
perhaps	O
less	O
controversially	O
)	O
,	O
it	O
may	O
be	O
considered	O
to	O
be	O
one	O
of	O
the	O
first	O
workstation	B-Device
systems	O
,	O
with	O
successors	O
such	O
as	O
the	O
Apollo	B-Device
workstations	B-Device
and	O
systems	O
by	O
Symbolics	O
(	O
designed	O
to	O
natively	O
run	O
Lisp	B-Language
as	O
a	O
development	O
environment	O
.	O
)	O
</s>
<s>
In	O
1976	O
to	O
1977	O
,	O
the	O
Swiss	O
computer	O
pioneer	O
Niklaus	O
Wirth	O
spent	O
a	O
sabbatical	O
at	O
PARC	O
and	O
was	O
excited	O
by	O
the	O
Alto	B-Device
.	O
</s>
<s>
Unable	O
to	O
bring	O
back	O
one	O
of	O
the	O
Alto	B-Device
systems	O
to	O
Europe	O
,	O
Wirth	O
decided	O
to	O
build	O
a	O
new	O
system	O
from	O
scratch	O
and	O
he	O
designed	O
with	O
his	O
group	O
the	O
Lilith	B-Device
.	O
</s>
<s>
Lilith	B-Device
was	O
ready	O
to	O
use	O
around	O
1980	O
,	O
quite	O
some	O
time	O
before	O
Apple	B-Device
Lisa	I-Device
and	O
Macintosh	B-Device
were	O
released	O
.	O
</s>
<s>
Around	O
1985	O
Wirth	O
started	O
a	O
complete	O
redesign	O
of	O
the	O
Lilith	B-Device
under	O
the	O
Name	O
"	B-Application
Project	I-Application
Oberon	I-Application
"	I-Application
.	O
</s>
<s>
In	O
1978	O
,	O
Xerox	O
donated	O
50	O
Altos	B-Device
to	O
the	O
Massachusetts	O
Institute	O
of	O
Technology	O
,	O
Stanford	O
University	O
,	O
Carnegie	O
Mellon	O
University	O
,	O
and	O
the	O
University	O
of	O
Rochester	O
.	O
</s>
<s>
The	O
National	O
Bureau	O
of	O
Standards	O
's	O
Institute	O
for	O
Computer	O
Sciences	O
in	O
Gaithersburg	O
,	O
Maryland	O
received	O
one	O
Alto	B-Device
in	O
late	O
1978	O
along	O
with	O
Xerox	O
Interim	O
File	O
System	O
(	O
IFS	O
)	O
file	O
servers	O
and	O
Dover	O
laser	O
printers	O
.	O
</s>
<s>
These	O
machines	O
were	O
the	O
inspiration	O
for	O
the	O
ETH	O
Zuerich	O
Lilith	B-Device
and	O
Three	O
Rivers	O
Company	O
PERQ	B-Device
workstations	I-Device
,	O
and	O
the	O
Stanford	O
University	O
Network	O
(	O
SUN	O
)	O
workstation	B-Device
,	O
which	O
was	O
eventually	O
marketed	O
by	O
a	O
spin-off	O
company	O
,	O
Sun	O
Microsystems	O
.	O
</s>
<s>
The	O
Apollo/Domain	B-Device
workstation	B-Device
was	O
heavily	O
influenced	O
by	O
the	O
Alto	B-Device
.	O
</s>
<s>
Following	O
the	O
acquisition	O
of	O
an	O
Alto	B-Device
,	O
the	O
White	O
House	O
information	O
systems	O
department	O
sought	O
to	O
lead	O
federal	O
computer	O
suppliers	O
in	O
its	O
direction	O
.	O
</s>
<s>
The	O
Executive	O
Office	O
of	O
the	O
President	O
of	O
the	O
United	O
States	O
(	O
EOP	O
)	O
issued	O
a	O
request	O
for	O
proposal	O
for	O
a	O
computer	O
system	O
to	O
replace	O
the	O
aging	O
Office	O
of	O
Management	O
and	O
Budget	O
(	O
OMB	O
)	O
budget	O
system	O
,	O
using	O
Alto-like	O
workstations	B-Device
,	O
connected	O
to	O
an	O
IBM-compatible	O
mainframe	B-Architecture
.	O
</s>
<s>
The	O
request	O
was	O
eventually	O
withdrawn	O
because	O
no	O
mainframe	B-Architecture
producer	O
could	O
supply	O
such	O
a	O
configuration	O
.	O
</s>
<s>
In	O
December	O
1979	O
,	O
Apple	O
Computer	O
's	O
co-founder	O
Steve	O
Jobs	O
visited	O
Xerox	O
PARC	O
,	O
where	O
he	O
was	O
shown	O
the	O
Smalltalk-80	B-Application
object-oriented	O
programming	O
environment	O
,	O
networking	O
,	O
and	O
most	O
importantly	O
the	O
WYSIWYG	B-Application
,	O
mouse-driven	O
graphical	B-Application
user	I-Application
interface	I-Application
provided	O
by	O
the	O
Alto	B-Device
.	O
</s>
<s>
At	O
the	O
time	O
,	O
he	O
did	O
n't	O
recognize	O
the	O
significance	O
of	O
the	O
first	O
two	O
,	O
but	O
was	O
excited	O
by	O
the	O
last	O
one	O
,	O
promptly	O
integrating	O
it	O
into	O
Apple	O
's	O
products	O
;	O
first	O
into	O
the	O
Lisa	B-Device
and	O
then	O
in	O
the	O
Macintosh	B-Device
,	O
attracting	O
several	O
key	O
researchers	O
to	O
work	O
in	O
his	O
company	O
.	O
</s>
<s>
In	O
1980-1981	O
,	O
Xerox	B-Device
Altos	I-Device
were	O
used	O
by	O
engineers	O
at	O
PARC	O
and	O
at	O
the	O
Xerox	O
System	O
Development	O
Department	O
to	O
design	O
the	O
Xerox	B-Operating_System
Star	I-Operating_System
workstations	B-Device
.	O
</s>
<s>
PARC	O
built	O
their	O
own	O
emulation	O
of	O
the	O
Digital	O
Equipment	O
Corporation	O
PDP-10	B-Device
named	O
the	O
MAXC	O
.	O
</s>
<s>
After	O
the	O
Alto	B-Device
,	O
PARC	O
developed	O
more	O
powerful	O
workstations	B-Device
(	O
none	O
intended	O
as	O
projects	O
)	O
informally	O
termed	O
"	O
the	O
D-machines	O
"	O
:	O
Dandelion	O
(	O
least	O
powerful	O
,	O
but	O
the	O
only	O
to	O
be	O
made	O
a	O
product	O
in	O
one	O
form	O
)	O
,	O
Dolphin	O
;	O
Dorado	O
(	O
most	O
powerful	O
;	O
an	O
emitter-coupled	B-General_Concept
logic	I-General_Concept
(	O
ECL	O
)	O
machine	O
)	O
;	O
and	O
hybrids	O
like	O
the	O
Dandel-Iris	O
.	O
</s>
<s>
Before	O
the	O
advent	O
of	O
personal	B-Device
computers	I-Device
such	O
as	O
the	O
Apple	B-Device
II	I-Device
in	O
1977	O
and	O
the	O
IBM	B-Device
Personal	I-Device
Computer	I-Device
(	O
IBM	B-Device
PC	I-Device
)	O
in	O
1981	O
,	O
the	O
computer	O
market	O
was	O
dominated	O
by	O
costly	O
mainframes	B-Architecture
and	O
minicomputers	B-Architecture
equipped	O
with	O
dumb	O
terminals	O
that	O
time-shared	O
the	O
processing	O
time	O
of	O
the	O
central	O
computer	O
.	O
</s>
<s>
When	O
Xerox	O
finally	O
entered	O
the	O
PC	O
market	O
with	O
the	O
Xerox	B-Device
820	I-Device
,	O
they	O
pointedly	O
rejected	O
the	O
Alto	B-Device
design	O
and	O
opted	O
instead	O
for	O
a	O
very	O
conventional	O
model	O
,	O
a	O
CP/M	B-Application
-based	O
machine	O
with	O
the	O
then-standard	O
80	O
by	O
24	O
character-only	O
monitor	O
and	O
no	O
mouse	B-Device
.	O
</s>
<s>
With	O
the	O
help	O
of	O
PARC	O
researchers	O
,	O
Xerox	O
eventually	O
developed	O
the	O
Xerox	B-Operating_System
Star	I-Operating_System
,	O
based	O
on	O
the	O
Dandelion	O
workstation	B-Device
,	O
and	O
later	O
the	O
cost	O
reduced	O
Star	O
,	O
the	O
6085	O
office	O
system	O
,	O
based	O
on	O
the	O
Daybreak	B-Device
workstation	B-Device
.	O
</s>
<s>
These	O
machines	O
,	O
based	O
on	O
the	O
'	O
Wildflower	O
 '	O
architecture	O
described	O
in	O
a	O
paper	O
by	O
Butler	O
Lampson	O
,	O
incorporated	O
most	O
of	O
the	O
Alto	B-Device
innovations	O
,	O
including	O
the	O
graphical	B-Application
user	I-Application
interface	I-Application
with	O
icons	O
,	O
windows	O
,	O
folders	O
,	O
Ethernet-based	O
local	O
networking	O
,	O
and	O
network-based	O
laser	O
printer	O
services	O
.	O
</s>
<s>
Xerox	O
only	O
realized	O
their	O
mistake	O
in	O
the	O
early	O
1980s	O
,	O
after	O
Apple	O
's	O
Macintosh	B-Device
revolutionized	O
the	O
PC	O
market	O
via	O
its	O
bitmap	O
display	B-Device
and	O
the	O
mouse-centered	O
interface	O
.	O
</s>
<s>
Both	O
of	O
these	O
were	O
copied	O
from	O
the	O
Alto	B-Device
.	O
</s>
<s>
While	O
the	O
Xerox	B-Operating_System
Star	I-Operating_System
series	O
was	O
a	O
relative	O
commercial	O
success	O
,	O
it	O
came	O
too	O
late	O
.	O
</s>
<s>
The	O
expensive	O
Xerox	O
workstations	B-Device
could	O
not	O
compete	O
against	O
the	O
cheaper	O
GUI-based	O
workstations	B-Device
that	O
arose	O
in	O
the	O
wake	O
of	O
the	O
first	O
Macintosh	B-Device
,	O
and	O
Xerox	O
eventually	O
quit	O
the	O
workstation	B-Device
market	O
for	O
good	O
.	O
</s>
