<s>
Real-Time	B-Operating_System
Executive	I-Operating_System
for	I-Operating_System
Multiprocessor	I-Operating_System
Systems	I-Operating_System
(	O
RTEMS	B-Operating_System
)	O
,	O
formerly	O
Real-Time	B-Operating_System
Executive	O
for	O
Missile	O
Systems	O
,	O
and	O
then	O
Real-Time	B-Operating_System
Executive	O
for	O
Military	O
Systems	O
,	O
is	O
a	O
real-time	B-Operating_System
operating	I-Operating_System
system	I-Operating_System
(	O
RTOS	B-Operating_System
)	O
designed	O
for	O
embedded	B-Architecture
systems	I-Architecture
.	O
</s>
<s>
It	O
is	O
free	B-License
and	I-License
open-source	I-License
software	I-License
.	O
</s>
<s>
Development	O
began	O
in	O
the	O
late	O
1980s	O
with	O
early	O
versions	O
available	O
via	O
File	B-Protocol
Transfer	I-Protocol
Protocol	I-Protocol
(	O
ftp	O
)	O
as	O
early	O
as	O
1993	O
.	O
</s>
<s>
OAR	O
Corporation	O
is	O
currently	O
managing	O
the	O
RTEMS	B-Operating_System
project	O
in	O
cooperation	O
with	O
a	O
steering	O
committee	O
which	O
includes	O
user	O
representatives	O
.	O
</s>
<s>
RTEMS	B-Operating_System
is	O
designed	O
for	O
real-time	B-Operating_System
,	O
embedded	B-Architecture
systems	I-Architecture
and	O
to	O
support	O
various	O
open	O
application	O
programming	O
interface	O
(	O
API	B-General_Concept
)	O
standards	O
including	O
Portable	O
Operating	O
System	O
Interface	O
(	O
POSIX	O
)	O
and	O
µITRON	O
.	O
</s>
<s>
The	O
API	B-General_Concept
now	O
known	O
as	O
the	O
Classic	O
RTEMS	B-Operating_System
API	B-General_Concept
was	O
originally	O
based	O
on	O
the	O
Real-Time	B-Operating_System
Executive	O
Interface	O
Definition	O
(	O
RTEID	O
)	O
specification	O
.	O
</s>
<s>
RTEMS	B-Operating_System
includes	O
a	O
port	O
of	O
the	O
FreeBSD	B-Operating_System
Internet	B-Protocol
protocol	I-Protocol
suite	I-Protocol
(	O
TCP/IP	B-Protocol
stack	I-Protocol
)	O
and	O
support	O
for	O
various	O
file	B-Application
systems	I-Application
including	O
Network	B-Protocol
File	I-Protocol
System	I-Protocol
(	O
NFS	O
)	O
and	O
File	B-Application
Allocation	I-Application
Table	I-Application
(	O
FAT	O
)	O
.	O
</s>
<s>
RTEMS	B-Operating_System
provides	O
extensive	O
and	O
,	O
and	O
even	O
a	O
alongside	O
many	O
other	O
facilities	O
.	O
</s>
<s>
RTEMS	B-Operating_System
has	O
been	O
ported	O
to	O
various	O
target	O
processor	O
architectures	O
:	O
</s>
<s>
RTEMS	B-Operating_System
is	O
used	O
in	O
many	O
application	O
domains	O
.	O
</s>
<s>
The	O
Experimental	B-Application
Physics	I-Application
and	I-Application
Industrial	I-Application
Control	I-Application
System	I-Application
(	O
EPICS	B-Application
)	O
community	O
includes	O
multiple	O
people	O
who	O
are	O
active	O
RTEMS	B-Operating_System
submitters	O
.	O
</s>
<s>
RTEMS	B-Operating_System
is	O
also	O
popular	O
for	O
space	O
uses	O
since	O
it	O
supports	O
multiple	O
microprocessors	O
developed	O
for	O
use	O
in	O
space	O
including	O
SPARC	B-Architecture
ERC32	B-General_Concept
and	O
LEON	B-General_Concept
,	O
MIPS	B-Device
Mongoose-V	B-General_Concept
,	O
ColdFire	B-Device
,	O
and	O
PowerPC	B-Architecture
architectures	O
,	O
which	O
are	O
available	O
in	O
space	O
hardened	O
models	O
.	O
</s>
<s>
RTEMS	B-Operating_System
is	O
currently	O
orbiting	O
Mars	O
as	O
part	O
of	O
the	O
Electra	O
software	O
radio	O
on	O
NASA	O
's	O
Mars	O
Reconnaissance	O
Orbiter	O
,	O
and	O
the	O
ESA	O
's	O
Trace	O
Gas	O
Orbiter	O
.	O
</s>
<s>
RTEMS	B-Operating_System
is	O
distributed	O
under	O
a	O
modified	B-Application
GNU	I-Application
General	I-Application
Public	I-Application
License	I-Application
(	O
GPL	B-License
)	O
,	O
allowing	O
linking	O
RTEMS	B-Operating_System
objects	O
with	O
other	O
files	O
without	O
needing	O
the	O
full	O
executable	O
to	O
be	O
covered	O
by	O
the	O
GPL	B-License
.	O
</s>
<s>
This	O
license	O
is	O
based	O
on	O
the	O
GNAT	B-Application
Modified	I-Application
General	I-Application
Public	I-Application
License	I-Application
with	O
the	O
language	O
modified	O
to	O
not	O
be	O
specific	O
to	O
the	O
programming	O
language	O
Ada	B-Language
.	O
</s>
