<s>
Chez	B-Language
Scheme	I-Language
is	O
a	O
programming	O
language	O
,	O
a	O
dialect	O
and	O
implementation	O
of	O
the	O
language	O
Scheme	B-Language
which	O
is	O
a	O
type	O
of	O
Lisp	B-Language
.	O
</s>
<s>
It	O
uses	O
an	O
incremental	B-Application
native-code	O
compiler	O
to	O
produce	O
native	O
binary	O
files	O
for	O
the	O
x86	B-Operating_System
(	O
IA-32	B-Device
,	O
x86-64	B-Device
)	O
,	O
PowerPC	B-Architecture
,	O
and	O
SPARC	B-Architecture
processor	I-Architecture
architectures	I-Architecture
.	O
</s>
<s>
It	O
is	O
free	B-License
and	I-License
open-source	I-License
software	I-License
released	O
under	O
an	O
Apache	B-Application
License	I-Application
,	I-Application
version	I-Application
2.0	I-Application
.	O
</s>
<s>
It	O
was	O
first	O
released	O
in	O
1985	O
,	O
by	O
R	O
.	O
Kent	O
Dybvig	O
,	O
originally	O
licensed	O
as	O
proprietary	B-Application
software	I-Application
,	O
and	O
then	O
released	O
as	O
open-source	B-Application
software	I-Application
on	O
GitHub	B-Application
on	O
2016-05-13	O
with	O
version	O
9.4	O
.	O
</s>
<s>
Petite	O
Chez	B-Language
Scheme	I-Language
is	O
a	O
sibling	O
implementation	O
which	O
uses	O
a	O
threaded	O
interpreter	O
design	O
instead	O
of	O
Chez	B-Language
Scheme	I-Language
's	O
incremental	B-Application
native-code	O
compiler	O
.	O
</s>
<s>
Programs	O
written	O
for	O
Chez	B-Language
Scheme	I-Language
run	O
unchanged	O
in	O
Petite	O
Chez	B-Language
Scheme	I-Language
,	O
as	O
long	O
as	O
they	O
do	O
not	O
depend	O
on	O
using	O
the	O
compiler	B-Language
(	O
for	O
example	O
foreign	B-Application
function	I-Application
interface	I-Application
is	O
only	O
available	O
in	O
the	O
compiler	B-Language
)	O
.	O
</s>
<s>
Petite	O
Chez	B-Language
Scheme	I-Language
was	O
originally	O
freely	O
distributable	O
and	O
is	O
now	O
distributed	O
open-source	B-Application
as	O
part	O
of	O
Chez	B-Language
Scheme	I-Language
.	O
</s>
<s>
The	O
first	O
version	O
of	O
Chez	B-Language
Scheme	I-Language
was	O
developed	O
by	O
R	O
.	O
Kent	O
Dybvig	O
and	O
completed	O
in	O
1984	O
.	O
</s>
<s>
Cadence	O
Research	O
Systems	O
developed	O
Chez	B-Language
Scheme	I-Language
until	O
the	O
company	O
was	O
purchased	O
by	O
Cisco	O
Systems	O
in	O
2011	O
.	O
</s>
<s>
Cisco	O
open-sourced	O
Chez	B-Language
Scheme	I-Language
in	O
2016	O
.	O
</s>
<s>
In	O
one	O
series	O
of	O
benchmarks	O
,	O
Chez	B-Language
Scheme	I-Language
was	O
among	O
the	O
fastest	O
available	O
Scheme	B-Language
implementations	O
on	O
the	O
Sun	B-Architecture
SPARC	I-Architecture
processor	O
architecture	O
,	O
while	O
Petite	O
Chez	B-Language
Scheme	I-Language
was	O
among	O
the	O
slowest	O
implementations	O
on	O
the	O
more	O
common	O
x86	B-Operating_System
(	O
Pentium	B-General_Concept
32-bit	O
)	O
processor	O
architecture	O
.	O
</s>
<s>
Chez	B-Language
Scheme	I-Language
has	O
a	O
windowing	B-Application
system	I-Application
and	O
computer	O
graphics	O
package	O
called	O
the	O
Scheme	B-Language
Widget	B-Library
Library	I-Library
,	O
and	O
is	O
supported	O
by	O
the	O
portable	O
SLIB	B-Application
library	B-Library
..	O
</s>
<s>
However	O
the	O
widget	B-Library
library	I-Library
is	O
no	O
longer	O
maintained	O
.	O
</s>
