<s>
Digigraphics	B-Algorithm
was	O
one	O
of	O
the	O
first	O
graphical	O
computer	B-Application
aided	I-Application
design	I-Application
systems	O
to	O
go	O
on	O
sale	O
.	O
</s>
<s>
Originally	O
developed	O
at	O
Itek	O
on	O
the	O
PDP-1	B-Device
as	O
EDM	O
(	O
Electronic	O
Drafting	O
Machine	O
)	O
,	O
the	O
efforts	O
were	O
purchased	O
by	O
Control	O
Data	O
Corporation	O
and	O
ported	O
to	O
their	O
machines	O
,	O
along	O
with	O
a	O
new	O
graphics	B-General_Concept
terminal	I-General_Concept
to	O
support	O
it	O
.	O
</s>
<s>
MIT	O
's	O
Lincoln	O
Laboratory	O
developed	O
the	O
first	O
high-speed	O
computer	O
in	O
the	O
form	O
of	O
Whirlwind	B-Device
,	O
as	O
part	O
of	O
the	O
US	O
Air	O
Force	O
's	O
SAGE	B-Device
project	I-Device
.	O
</s>
<s>
SAGE	B-Device
not	O
only	O
required	O
high-speed	O
computers	O
,	O
but	O
also	O
graphical	O
displays	O
and	O
light	B-Device
pens	I-Device
to	O
operate	O
them	O
in	O
real-time	O
.	O
</s>
<s>
The	O
ideas	O
developed	O
during	O
the	O
SAGE	B-Device
program	O
"	O
leaked	O
out	O
"	O
into	O
the	O
industry	O
as	O
SAGE	B-Device
wound	O
down	O
and	O
its	O
many	O
members	O
moved	O
on	O
to	O
other	O
projects	O
.	O
</s>
<s>
Ken	O
Olsen	O
formed	O
Digital	O
Equipment	O
Corporation	O
(	O
DEC	O
)	O
and	O
took	O
many	O
of	O
the	O
early	O
SAGE	B-Device
programmers	O
with	O
them	O
,	O
Jack	O
Gilmore	O
and	O
Charles	O
Adams	O
started	O
Charles	O
W	O
.	O
Adams	O
Associates	O
,	O
one	O
of	O
the	O
first	O
programming	O
companies	O
,	O
and	O
Norm	O
Taylor	O
went	O
to	O
work	O
at	O
Itek	O
,	O
who	O
was	O
attempting	O
to	O
build	O
a	O
computerized	O
machine	O
for	O
retrieving	O
photographs	O
from	O
a	O
large	O
library	O
.	O
</s>
<s>
Taylor	O
convinced	O
Itek	O
's	O
management	O
to	O
fund	O
development	O
,	O
finally	O
receiving	O
the	O
go-ahead	O
in	O
August	O
1960	O
,	O
retaining	O
Adams	O
Associates	O
to	O
write	O
the	O
software	O
The	O
natural	O
choice	O
for	O
the	O
host	O
computer	O
was	O
DEC	O
's	O
newly	O
released	O
PDP-1	B-Device
.	O
</s>
<s>
The	O
PDP-1	B-Device
had	O
many	O
of	O
the	O
same	O
features	O
as	O
the	O
earlier	O
Lincoln	O
Lab	O
machines	O
,	O
including	O
an	O
optional	O
vector	B-General_Concept
display	I-General_Concept
and	O
light	B-Device
pen	I-Device
support	O
.	O
</s>
<s>
The	O
PDP-1	B-Device
was	O
based	O
on	O
an	O
18-bit	O
word	O
(	O
1/2	O
the	O
common	O
mainframe	O
36-bits	O
)	O
,	O
had	O
a	O
4,000	O
-word	O
core	B-General_Concept
memory	I-General_Concept
,	O
and	O
ran	O
at	O
about	O
0.1	O
MIPS	O
.	O
</s>
<s>
Itek	O
's	O
PDP-1	B-Device
was	O
the	O
second	O
one	O
to	O
be	O
delivered	O
to	O
a	O
customer	O
,	O
the	O
first	O
being	O
to	O
MIT	O
's	O
Project	O
MAC	O
.	O
</s>
<s>
A	O
new	O
25inch	O
tube	O
was	O
used	O
,	O
larger	O
than	O
the	O
PDP-1	B-Device
'	O
s	O
standard	O
16inch	O
Type	O
30	O
,	O
but	O
packaged	O
in	O
a	O
similar	O
hexagonal	O
case	O
.	O
</s>
<s>
Input	O
was	O
via	O
a	O
combination	O
of	O
light	B-Device
pen	I-Device
for	O
pointing	O
,	O
and	O
the	O
PDP-1	B-Device
'	O
s	O
front	O
panel	O
switches	O
for	O
commands	O
.	O
</s>
<s>
Normally	O
the	O
PDP-1	B-Device
display	O
was	O
driven	O
in	O
software	O
,	O
so	O
as	O
the	O
complexity	O
of	O
the	O
drawings	O
increased	O
,	O
performance	O
decreased	O
.	O
</s>
<s>
Itek	O
addressed	O
this	O
problem	O
by	O
developing	O
a	O
"	O
display	O
processor	O
"	O
that	O
would	O
offload	O
the	O
task	O
of	O
refreshing	O
the	O
screen	O
so	O
the	O
computer	O
could	O
be	O
used	O
solely	O
for	O
processing.Vector	O
information	O
was	O
stored	O
on	O
the	O
outer	O
tracks	O
of	O
a	O
36inch	O
hard	B-Device
disk	I-Device
supplied	O
by	O
Telex	O
.	O
</s>
<s>
By	O
simply	O
pressing	O
buttons	O
and	O
sketching	O
with	O
the	O
light	B-Device
pen	I-Device
,	O
the	O
engineer	O
may	O
enter	O
into	O
a	O
running	O
dialogue	O
with	O
an	O
EDM	O
,	O
recall	O
any	O
of	O
his	O
earlier	O
drawings	O
to	O
the	O
screen	O
in	O
a	O
millisecond	O
and	O
alter	O
its	O
lines	O
and	O
curves	O
at	O
will	O
.	O
</s>
<s>
The	O
US	O
Air	O
Force	O
purchased	O
one	O
system	O
for	O
use	O
at	O
the	O
Lincoln	O
Labs	O
on	O
the	O
PDP-1	B-Device
that	O
drove	O
their	O
Experimental	O
Dynamic	O
Processor	O
,	O
or	O
DX-1	O
.	O
</s>
<s>
This	O
version	O
used	O
a	O
magnetic	B-General_Concept
drum	I-General_Concept
in	O
place	O
of	O
the	O
disk	O
,	O
its	O
increased	O
performance	O
allowing	O
more	O
data	O
to	O
be	O
stored	O
before	O
performance	O
became	O
an	O
issue	O
.	O
</s>
<s>
EDM	O
was	O
not	O
the	O
only	O
CAD	B-Application
system	O
being	O
developed	O
at	O
the	O
time	O
.	O
</s>
<s>
In	O
spite	O
of	O
starting	O
at	O
about	O
the	O
same	O
time	O
,	O
Digigraphics	B-Algorithm
beat	O
their	O
DAC-1	B-Algorithm
to	O
market	O
by	O
the	O
better	O
part	O
of	O
a	O
year	O
.	O
</s>
<s>
Versions	O
of	O
the	O
basic	O
system	O
were	O
later	O
ported	O
to	O
other	O
CDC	O
computers	O
,	O
including	O
the	O
6000	B-Device
family	I-Device
,	O
which	O
could	O
support	O
several	O
274	O
's	O
on	O
a	O
single	O
machine	O
.	O
</s>
<s>
Over	O
the	O
next	O
few	O
years	O
CDC	O
sold	O
a	O
small	O
number	O
of	O
the	O
Digigraphics	B-Algorithm
systems	O
,	O
first	O
to	O
aerospace	O
companies	O
including	O
Lockheed	O
and	O
Martin	O
Marietta	O
,	O
and	O
later	O
to	O
the	O
US	O
Navy	O
,	O
for	O
use	O
in	O
submarine	O
design	O
.	O
</s>
