<s>
Zephyr	B-Application
(	O
)	O
is	O
a	O
small	O
real-time	B-Operating_System
operating	I-Operating_System
system	I-Operating_System
(	O
RTOS	B-Operating_System
)	O
for	O
connected	O
,	O
resource-constrained	O
and	O
embedded	B-Architecture
devices	I-Architecture
(	O
with	O
an	O
emphasis	O
on	O
microcontrollers	B-Architecture
)	O
supporting	O
multiple	O
architectures	O
and	O
released	O
under	O
the	O
Apache	B-Application
License	I-Application
2.0	O
.	O
</s>
<s>
Zephyr	B-Application
includes	O
a	O
kernel	B-Operating_System
,	O
and	O
all	O
components	O
and	O
libraries	B-Library
,	O
device	B-Application
drivers	I-Application
,	O
protocol	B-Protocol
stacks	I-Protocol
,	O
file	B-Application
systems	I-Application
,	O
and	O
firmware	O
updates	O
,	O
needed	O
to	O
develop	O
full	O
application	B-Application
software	I-Application
.	O
</s>
<s>
Zephyr	B-Application
originated	O
from	O
Virtuoso	O
RTOS	B-Operating_System
for	O
digital	B-Architecture
signal	I-Architecture
processors	I-Architecture
(	O
DSPs	O
)	O
.	O
</s>
<s>
In	O
November	O
2015	O
,	O
Wind	O
River	O
Systems	O
renamed	O
the	O
operating	B-General_Concept
system	I-General_Concept
to	O
Rocket	O
,	O
made	O
it	O
open-source	B-License
and	O
royalty-free	O
.	O
</s>
<s>
Compared	O
to	O
Wind	O
River	O
's	O
other	O
RTOS	B-Operating_System
,	O
VxWorks	B-Operating_System
,	O
Rocket	O
had	O
a	O
much	O
smaller	O
memory	O
needs	O
,	O
especially	O
suitable	O
for	O
sensors	O
and	O
single-function	O
embedded	B-Architecture
devices	I-Architecture
.	O
</s>
<s>
Rocket	O
could	O
fit	O
into	O
as	O
little	O
as	O
4	O
KB	O
of	O
memory	O
,	O
while	O
VxWorks	B-Operating_System
needed	O
200	O
KB	O
or	O
more	O
.	O
</s>
<s>
In	O
February	O
2016	O
,	O
Rocket	O
became	O
a	O
hosted	O
collaborative	O
project	O
of	O
the	B-Operating_System
Linux	I-Operating_System
Foundation	I-Operating_System
under	O
the	O
name	O
Zephyr	B-Application
.	O
</s>
<s>
Wind	O
River	O
Systems	O
contributed	O
the	O
Rocket	O
kernel	B-Operating_System
to	O
Zephyr	B-Application
,	O
but	O
still	O
provided	O
Rocket	O
to	O
its	O
clients	O
,	O
charging	O
them	O
for	O
the	O
cloud	O
services	O
.	O
</s>
<s>
As	O
a	O
result	O
,	O
Rocket	O
became	O
"	O
essentially	O
the	O
commercial	O
version	O
of	O
Zephyr	B-Application
"	O
.	O
</s>
<s>
Since	O
then	O
,	O
early	O
members	O
and	O
supporters	O
of	O
Zephyr	B-Application
include	O
Intel	O
,	O
NXP	O
Semiconductors	O
,	O
Synopsys	O
,	O
Linaro	O
,	O
Texas	O
Instruments	O
,	O
DeviceTone	O
,	O
Nordic	O
Semiconductor	O
,	O
Oticon	O
,	O
and	O
Bose	O
.	O
</s>
<s>
,	O
Zephyr	B-Application
had	O
the	O
largest	O
number	O
of	O
contributors	O
and	O
commits	O
compared	O
to	O
other	O
RTOSes	O
(	O
including	O
Mbed	B-Operating_System
,	O
RT-Thread	B-Operating_System
,	O
NuttX	B-Operating_System
,	O
and	O
RIOT	B-Device
)	O
.	O
</s>
<s>
Zephyr	B-Application
intends	O
to	O
provide	O
all	O
components	O
needed	O
to	O
develop	O
resource-constrained	O
and	O
embedded	O
or	O
microcontroller-based	O
applications	O
.	O
</s>
<s>
Zephyr	B-Application
uses	O
Kconfig	B-Application
and	O
devicetree	B-Operating_System
as	O
its	O
configuration	O
systems	O
,	O
inherited	O
from	O
the	O
Linux	B-Operating_System
kernel	I-Operating_System
but	O
implemented	O
in	O
the	O
programming	O
language	O
Python	B-Language
for	O
portability	O
to	O
non-Unix	O
operating	O
systems	O
.	O
</s>
<s>
The	O
RTOS	B-Operating_System
build	O
system	O
is	O
based	O
on	O
CMake	B-Language
,	O
which	O
allows	O
Zephyr	B-Application
applications	O
to	O
be	O
built	O
on	O
Linux	B-Application
,	O
macOS	B-Application
,	O
and	O
Microsoft	B-Application
Windows	I-Application
.	O
</s>
<s>
Early	O
Zephyr	B-Application
kernels	B-Operating_System
used	O
a	O
dual	O
nanokernel	B-Operating_System
plus	I-Operating_System
microkernel	I-Operating_System
design	O
.	O
</s>
<s>
In	O
December	O
2016	O
,	O
with	O
Zephyr	B-Application
1.6	O
,	O
this	O
changed	O
to	O
a	O
monolithic	B-Operating_System
kernel	I-Operating_System
.	O
</s>
<s>
The	O
kernel	B-Operating_System
offers	O
several	O
features	O
that	O
distinguish	O
it	O
from	O
other	O
small	O
OSes	O
:	O
</s>
<s>
Also	O
,	O
being	O
owned	O
and	O
supported	O
by	O
a	O
community	O
means	O
the	O
world	O
's	O
open	B-License
source	I-License
developers	O
are	O
vetting	O
the	O
code	O
,	O
which	O
significantly	O
increases	O
security	O
.	O
</s>
