<s>
River	B-Language
Trail	I-Language
(	O
also	O
known	O
as	O
Parallel	B-Language
JavaScript	I-Language
)	O
is	O
an	O
open-source	B-Application
software	I-Application
engine	O
designed	O
by	O
Intel	O
for	O
executing	O
JavaScript	B-Language
code	O
using	O
parallel	B-Operating_System
computing	I-Operating_System
on	O
multi-core	B-Architecture
processors	I-Architecture
.	O
</s>
<s>
River	B-Language
Trail	I-Language
was	O
announced	O
at	O
the	O
Intel	O
Developer	O
Forum	O
in	O
September	O
2011	O
,	O
and	O
demonstrated	O
using	O
a	O
Firefox	B-Application
extension	O
developed	O
by	O
Intel	O
.	O
</s>
<s>
Brendan	O
Eich	O
,	O
the	O
original	O
author	O
of	O
JavaScript	B-Language
,	O
promised	O
that	O
he	O
would	O
promote	O
River	B-Language
Trail	I-Language
within	O
Ecma	O
International	O
,	O
saying	O
"	O
The	O
demo	O
shows	O
a	O
15x	O
speedup	O
over	O
serial	O
JavaScript	B-Language
.	O
</s>
<s>
–	O
all	O
written	O
in	O
memory-safe	O
,	O
clean	O
,	O
functional	O
JavaScript	B-Language
,	O
without	O
threads	O
and	O
their	O
data	O
races	O
and	O
deadlocks.	O
"	O
</s>
<s>
Because	O
River	B-Language
Trail	I-Language
leverages	O
Intel	O
's	O
OpenCL	B-Application
SDK	O
it	O
can	O
exploit	O
multiple	O
CPU	B-Architecture
cores	I-Architecture
as	O
well	O
as	O
data	B-Operating_System
parallel	I-Operating_System
instructions	O
(	O
ex	O
.	O
</s>
<s>
AVX	B-General_Concept
,	O
SSE	B-General_Concept
)	O
and	O
the	O
speedup	O
can	O
be	O
greater	O
than	O
the	O
CPU	B-Architecture
core	I-Architecture
count	O
would	O
imply	O
.	O
</s>
<s>
A	O
native	O
implementation	O
of	O
River	B-Language
Trail	I-Language
in	O
Firefox	B-Application
's	O
SpiderMonkey	B-Language
JavaScript	B-Language
engine	I-Language
was	O
announced	O
in	O
September	O
2012	O
and	O
was	O
added	O
to	O
nightly	O
Firefox	B-Application
builds	O
in	O
April	O
2013	O
.	O
</s>
<s>
By	O
January	O
2015	O
,	O
the	O
code	O
had	O
been	O
removed	O
from	O
Firefox	B-Application
.	O
</s>
<s>
To	O
use	O
the	O
engine	O
scripts	O
uses	O
a	O
special	O
API	B-General_Concept
,	O
based	O
on	O
three	O
pillars	O
:	O
a	O
type	O
called	O
ParallelArray	O
,	O
several	O
methods	O
of	O
Prototype	B-Application
of	O
ParallelArray	O
,	O
and	O
elementary	O
functions	O
.	O
</s>
