<s>
PCB	B-Language
is	O
a	O
free	B-License
and	I-License
open-source	I-License
software	I-License
suite	O
for	O
electronic	O
design	O
automation	O
(	O
EDA	O
)	O
-	O
for	O
printed	O
circuit	O
boards	O
(	O
PCB	B-Language
)	O
layout	O
.	O
</s>
<s>
It	O
uses	O
GTK+	B-Application
for	O
its	O
GUI	O
widgets	O
.	O
</s>
<s>
PCB	B-Language
was	O
first	O
written	O
by	O
Thomas	O
Nau	O
for	O
an	O
Atari	B-Device
ST	I-Device
in	O
1990	O
and	O
ported	O
to	O
UNIX	B-Operating_System
and	O
X11	B-Operating_System
in	O
1994	O
.	O
</s>
<s>
Initially	O
PCB	B-Language
was	O
not	O
intended	O
to	O
be	O
a	O
professional	O
layout	O
system	O
but	O
as	O
a	O
tool	O
for	O
individuals	O
to	O
do	O
small-scale	O
development	O
of	O
hardware	O
.	O
</s>
<s>
This	O
made	O
PCB	B-Language
easier	O
to	O
use	O
and	O
increased	O
its	O
popularity	O
.	O
</s>
<s>
Harry	O
Eaton	O
took	O
over	O
PCB	B-Language
development	O
beginning	O
with	O
Release	O
1.5	O
,	O
although	O
he	O
contributed	O
some	O
code	O
from	O
Release	O
1.4.3	O
.	O
</s>
<s>
PCB	B-Language
includes	O
a	O
topological	O
autorouter	O
named	O
Toporouter	B-Algorithm
,	O
developed	O
by	O
Anthony	O
Blake	O
in	O
a	O
Google-funded	O
open	B-Application
source	I-Application
project	O
mentored	O
by	O
DJ	B-Application
Delorie	I-Application
in	O
2008	O
.	O
</s>
<s>
This	O
router	O
has	O
meanwhile	O
been	O
adapted	O
for	O
use	O
with	O
the	O
open-source	B-Application
KiCad	B-Language
project	O
as	O
well	O
.	O
</s>
<s>
In	O
2013	O
,	O
pcb-rnd	B-Language
was	O
forked	O
from	O
PCB	B-Language
.	O
</s>
