<s>
An	O
embedded	B-Operating_System
operating	I-Operating_System
system	I-Operating_System
is	O
an	O
operating	B-General_Concept
system	I-General_Concept
for	O
embedded	B-Architecture
computer	I-Architecture
systems	I-Architecture
.	O
</s>
<s>
Embedded	B-Operating_System
operating	I-Operating_System
systems	I-Operating_System
are	O
computer	O
systems	O
designed	O
to	O
increase	O
functionality	O
and	O
reliability	O
for	O
achieving	O
a	O
specific	O
task	O
.	O
</s>
<s>
Resource	O
efficiency	O
comes	O
at	O
the	O
cost	O
of	O
losing	O
some	O
functionality	O
or	O
granularity	O
that	O
larger	O
computer	B-General_Concept
operating	I-General_Concept
systems	I-General_Concept
provide	O
,	O
including	O
functions	O
that	O
may	O
not	O
be	O
used	O
by	O
the	O
specialized	O
applications	O
run	O
.	O
</s>
<s>
Depending	O
on	O
the	O
method	O
used	O
for	O
multitasking	O
,	O
this	O
type	O
of	O
OS	O
is	O
frequently	O
considered	O
a	O
real-time	B-Operating_System
operating	I-Operating_System
system	I-Operating_System
or	O
RTOS	B-Operating_System
.	O
</s>
<s>
Embedded	B-Architecture
systems	I-Architecture
are	O
mostly	O
used	O
as	O
Real-time	B-Operating_System
operating	I-Operating_System
systems	I-Operating_System
.	O
</s>
<s>
All	O
embedded	B-Architecture
systems	I-Architecture
contain	O
a	O
processor	O
and	O
software	O
.	O
</s>
<s>
There	O
must	O
be	O
a	O
place	O
for	O
embedded	B-Application
software	I-Application
to	O
store	O
the	O
executable	B-Application
code	I-Application
and	O
temporary	O
storage	O
for	O
run-time	B-Library
data	O
manipulations	O
.	O
</s>
<s>
These	O
take	O
the	O
form	O
of	O
ROM	B-Device
and	O
RAM	B-Architecture
,	O
respectively	O
.	O
</s>
<s>
All	O
embedded	B-Architecture
systems	I-Architecture
must	O
also	O
contain	O
some	O
form	O
of	O
inputs	O
and	O
outputs	O
to	O
function	O
.	O
</s>
<s>
Within	O
the	O
exception	O
of	O
these	O
few	O
common	O
features	O
,	O
the	O
rest	O
of	O
the	O
embedded	B-Architecture
hardware	I-Architecture
is	O
usually	O
unique	O
and	O
varies	O
from	O
application	O
to	O
application	O
.	O
</s>
<s>
The	O
hardware	O
running	O
an	O
embedded	B-Operating_System
operating	I-Operating_System
system	I-Operating_System
can	O
be	O
very	O
limited	O
in	O
resources	O
;	O
therefore	O
the	O
embedded	O
design	O
of	O
these	O
operating	B-General_Concept
systems	I-General_Concept
may	O
have	O
a	O
narrow	O
scope	O
tailored	O
to	O
a	O
specific	O
application	O
to	O
achieve	O
the	O
desired	O
operation	O
under	O
these	O
constraints	O
.	O
</s>
<s>
The	O
embedded	B-Operating_System
operating	I-Operating_System
system	I-Operating_System
that	O
organizes	O
and	O
controls	O
the	O
hardware	O
usually	O
determines	O
the	O
rest	O
of	O
the	O
embedded	B-Architecture
hardware	I-Architecture
needed	O
.	O
</s>
<s>
To	O
take	O
better	O
advantage	O
of	O
the	O
processing	O
power	O
of	O
the	O
CPU	B-General_Concept
,	O
software	O
developers	O
may	O
write	O
critical	O
code	O
directly	O
in	O
assembly	B-Language
.	O
</s>
<s>
Often	O
,	O
embedded	B-Operating_System
operating	I-Operating_System
systems	I-Operating_System
are	O
written	O
entirely	O
in	O
more	O
portable	O
languages	O
,	O
like	O
C	B-Language
,	O
however	O
.	O
</s>
<s>
An	O
important	O
difference	O
between	O
most	O
embedded	B-Operating_System
operating	I-Operating_System
systems	I-Operating_System
and	O
desktop	B-General_Concept
operating	I-General_Concept
systems	I-General_Concept
is	O
that	O
the	O
application	O
,	O
including	O
the	O
operating	B-General_Concept
system	I-General_Concept
,	O
is	O
usually	O
statically	O
linked	O
into	O
a	O
single	O
executable	B-Application
image	O
.	O
</s>
<s>
Unlike	O
a	O
desktop	B-General_Concept
operating	I-General_Concept
system	I-General_Concept
,	O
the	O
embedded	B-Operating_System
operating	I-Operating_System
system	I-Operating_System
does	O
not	O
load	O
and	O
execute	O
many	O
applications	O
.	O
</s>
<s>
In	O
the	O
1980s	O
,	O
while	O
the	O
embedded	B-Architecture
systems	I-Architecture
applications	O
became	O
more	O
complex	O
,	O
the	O
embedded	B-Operating_System
operating	I-Operating_System
system	I-Operating_System
with	O
a	O
real-time	O
multitasking	O
kernel	O
could	O
not	O
meet	O
the	O
requirement	O
of	O
embedded	O
development	O
.	O
</s>
<s>
It	O
began	O
to	O
develop	O
into	O
a	O
complete	O
real-time	O
multitasking	O
Operating	B-General_Concept
System	I-General_Concept
(	O
RTOS	B-Operating_System
)	O
that	O
included	O
a	O
network	O
,	O
file	O
,	O
development	O
and	O
debugging	O
environment	O
.	O
</s>
<s>
Nowadays	O
,	O
RTOS	B-Operating_System
has	O
formed	O
an	O
industry	O
in	O
the	O
world	O
.	O
</s>
<s>
Then	O
in	O
1993	O
,	O
Ready	O
System	O
and	O
the	O
famous	O
Silicon	O
Valley	O
embedded	B-Application
software	I-Application
company	O
Microtec	O
Research	O
Merger	O
developed	O
two	O
new	O
RTOS	B-Operating_System
kernels	O
VRTX32	O
and	O
VRTXsa	O
,	O
based	O
on	O
VRTXmc	B-Operating_System
.	O
</s>
<s>
Microsoft	O
,	O
also	O
released	O
its	O
own	O
embedded	O
460	O
operating	B-General_Concept
system	I-General_Concept
in	O
1996	O
.	O
</s>
<s>
The	O
embedded	B-Operating_System
operating	I-Operating_System
system	I-Operating_System
is	O
WinCE	B-Operating_System
,	O
which	O
was	O
originally	O
based	O
on	O
Windows	B-Application
95	I-Application
in	O
the	O
1.0	O
version	O
,	O
they	O
subsequently	O
released	O
other	O
versions	O
,	O
supporting	O
x86	B-Operating_System
,	O
ARM	B-Architecture
,	O
SH4	O
,	O
MIPS	B-Device
and	O
other	O
processor	O
architectures	O
.	O
</s>
<s>
WinCE	B-Operating_System
is	O
now	O
defunct	O
,	O
with	O
mainstream	O
support	O
discontinued	O
in	O
2018	O
.	O
</s>
<s>
Nowadays	O
,	O
many	O
embedded	B-Architecture
devices	I-Architecture
are	O
used	O
in	O
the	O
system	O
of	O
Internet	B-Operating_System
of	I-Operating_System
Things	I-Operating_System
and	O
hundreds	O
of	O
sensors	O
are	O
used	O
in	O
a	O
car	O
.	O
</s>
<s>
Compared	O
with	O
the	O
traditional	O
embedded	B-Architecture
system	I-Architecture
,	O
the	B-Operating_System
Internet	I-Operating_System
of	I-Operating_System
Things	I-Operating_System
system	O
requires	O
lower	O
power	O
consumption	O
,	O
more	O
safety	O
and	O
reliability	O
,	O
and	O
has	O
the	O
ability	O
of	O
ad	B-Protocol
hoc	I-Protocol
network	I-Protocol
.	O
</s>
<s>
The	O
communication	O
section	O
needs	O
to	O
meet	O
the	O
conversion	O
between	O
various	O
communication	O
protocols	O
,	O
and	O
the	O
application	O
layer	O
must	O
have	O
the	O
ability	O
of	O
cloud	B-Architecture
computing	I-Architecture
.	O
</s>
<s>
Due	O
to	O
this	O
,	O
new	O
embedded	B-Operating_System
operating	I-Operating_System
systems	I-Operating_System
have	O
emerged	O
and	O
become	O
popular	O
,	O
like	O
Embedded	B-Application
Linux	I-Application
(	O
including	O
OpenWrt	B-Application
,	O
Zeroshell	B-Protocol
,	O
Android	B-Application
,	O
LineageOS	B-Application
,	O
LEDE	B-Language
,	O
LibreCMC	B-Application
)	O
,	O
NetBSD	B-Device
,	O
ThreadX	B-Operating_System
,	O
FreeRTOS	B-Operating_System
,	O
etc	O
.	O
</s>
<s>
Many	O
Linux-based	O
projects	O
,	O
toolkits	O
,	O
frameworks	O
etc.	O
,	O
have	O
also	O
emerged	O
for	O
embedded	B-Architecture
systems	I-Architecture
.	O
</s>
<s>
Some	O
notable	O
examples	O
include	O
OpenEmbedded	B-Application
,	O
BusyBox	B-Application
,	O
uClibc	B-Language
,	O
musl	B-Language
libc	B-Language
,	O
buildroot	B-Application
,	O
etc	O
.	O
</s>
