<s>
Azure	B-Operating_System
RTOS	I-Operating_System
ThreadX	B-Operating_System
is	O
a	O
highly	O
deterministic	O
,	O
embedded	B-Application
real-time	B-Operating_System
operating	I-Operating_System
system	I-Operating_System
(	O
RTOS	B-Operating_System
)	O
programmed	O
mostly	O
in	O
the	O
language	O
C	B-Language
.	O
</s>
<s>
ThreadX	B-Operating_System
was	O
originally	O
developed	O
and	O
marketed	O
by	O
Express	B-Operating_System
Logic	I-Operating_System
of	O
San	O
Diego	O
,	O
California	O
,	O
United	O
States	O
.	O
</s>
<s>
The	O
author	O
of	O
ThreadX	B-Operating_System
(	O
and	O
the	O
original	O
author	O
of	O
the	O
Nucleus	B-Operating_System
RTOS	I-Operating_System
in	O
1990	O
)	O
is	O
William	O
Lamie	O
,	O
who	O
was	O
also	O
President	O
and	O
CEO	O
of	O
Express	B-Operating_System
Logic	I-Operating_System
.	O
</s>
<s>
Express	B-Operating_System
Logic	I-Operating_System
was	O
purchased	O
for	O
an	O
undisclosed	O
sum	O
by	O
Microsoft	O
on	O
April	O
18	O
,	O
2019	O
.	O
</s>
<s>
The	O
name	O
ThreadX	B-Operating_System
is	O
derived	O
from	O
the	O
threads	B-Protocol
that	O
are	O
used	O
as	O
the	O
executable	O
elements	O
,	O
and	O
the	O
letter	O
X	O
represents	O
context	B-Operating_System
switching	I-Operating_System
,	O
i.e.	O
,	O
it	O
switches	O
threads	B-Protocol
.	O
</s>
<s>
ThreadX	B-Operating_System
provides	O
priority-based	O
,	O
preemptive	O
scheduling	O
,	O
fast	O
interrupt	B-Application
response	O
,	O
memory	B-General_Concept
management	I-General_Concept
,	O
interthread	O
communication	O
,	O
mutual	B-Operating_System
exclusion	I-Operating_System
,	O
event	O
notification	O
,	O
and	O
thread	B-Protocol
synchronization	O
features	O
.	O
</s>
<s>
Major	O
distinguishing	O
technology	O
characteristics	O
of	O
ThreadX	B-Operating_System
include	O
preemption-threshold	O
,	O
priority	B-Operating_System
inheritance	I-Operating_System
,	O
efficient	O
timer	O
management	O
,	O
fast	O
software	O
timers	O
,	O
picokernel	O
design	O
,	O
event-chaining	O
,	O
and	O
small	O
size	O
:	O
minimal	O
size	O
on	O
an	O
ARM	B-Architecture
architecture	I-Architecture
processor	O
is	O
about	O
2	O
KB	O
.	O
</s>
<s>
ThreadX	B-Operating_System
supports	O
multi-core	B-Architecture
processor	I-Architecture
environments	O
via	O
either	O
asymmetric	B-Operating_System
multiprocessing	I-Operating_System
(	O
AMP	O
)	O
or	O
symmetric	B-Operating_System
multiprocessing	I-Operating_System
(	O
SMP	O
)	O
.	O
</s>
<s>
Application	O
thread	B-Protocol
isolation	O
with	O
memory	B-General_Concept
management	I-General_Concept
unit	I-General_Concept
(	O
MMU	O
)	O
or	O
memory	B-General_Concept
protection	I-General_Concept
unit	I-General_Concept
(	O
MPU	O
)	O
memory	O
protection	O
is	O
available	O
with	O
ThreadX	B-Operating_System
Modules	O
.	O
</s>
<s>
ThreadX	B-Operating_System
has	O
extensive	O
safety	O
certifications	O
from	O
Technischer	O
Überwachungsverein	O
(	O
TÜV	O
,	O
English	O
:	O
Technical	O
Inspection	O
Association	O
)	O
and	O
UL	O
(	O
formerly	O
Underwriters	O
Laboratories	O
)	O
and	O
is	O
Motor	O
Industry	O
Software	O
Reliability	O
Association	O
MISRA	B-Language
C	I-Language
compliant	O
.	O
</s>
<s>
ThreadX	B-Operating_System
is	O
the	O
foundation	O
of	O
Express	B-Operating_System
Logic	I-Operating_System
's	O
X-Ware	O
Internet	B-Operating_System
of	I-Operating_System
things	I-Operating_System
(	O
IoT	B-Operating_System
)	O
platform	O
,	O
which	O
also	O
includes	O
embedded	B-Application
file	B-Application
system	I-Application
support	O
(	O
FileX	O
)	O
,	O
embedded	B-Application
UI	O
support	O
(	O
GUIX	O
)	O
,	O
embedded	B-Application
Internet	B-Protocol
protocol	I-Protocol
suite	I-Protocol
(	O
TCP/IP	B-Protocol
)	O
and	O
cloud	O
connectivity	O
(	O
NetX/NetX	O
Duo	O
)	O
,	O
and	O
Universal	O
Serial	O
Bus	O
(	O
USB	B-Protocol
)	O
support	O
(	O
USBX	O
)	O
.	O
</s>
<s>
ThreadX	B-Operating_System
has	O
won	O
high	O
appraisal	O
from	O
developers	O
and	O
is	O
a	O
very	O
popular	O
RTOS	B-Operating_System
.	O
</s>
<s>
,	O
according	O
to	O
marketing	O
research	O
firm	O
VDC	O
Research	O
,	O
the	O
ThreadX	B-Operating_System
RTOS	B-Operating_System
has	O
become	O
one	O
of	O
the	O
most	O
popular	O
RTOSes	O
in	O
the	O
world	O
,	O
having	O
been	O
deployed	O
in	O
over	O
6.2	O
billion	O
devices	O
,	O
including	O
consumer	O
electronics	O
,	O
medical	O
devices	O
,	O
data	O
networking	O
applications	O
,	O
and	O
SoCs	O
.	O
</s>
<s>
ThreadX	B-Operating_System
is	O
distributed	O
using	O
a	O
marketing	O
model	O
in	O
which	O
source	O
code	O
is	O
provided	O
and	O
licenses	B-License
are	O
royalty-free	O
.	O
</s>
<s>
ThreadX	B-Operating_System
was	O
first	O
introduced	O
in	O
1997	O
.	O
</s>
<s>
ThreadX	B-Operating_System
4	O
was	O
introduced	O
in	O
2001	O
.	O
</s>
<s>
ThreadX	B-Operating_System
5	O
was	O
introduced	O
in	O
2005	O
,	O
and	O
is	O
the	O
latest	O
version	O
.	O
</s>
<s>
FileX	O
–	O
the	O
embedded	B-Application
file	B-Application
system	I-Application
for	O
ThreadX	B-Operating_System
was	O
introduced	O
in	O
1999	O
.	O
</s>
<s>
NetX	O
–	O
the	O
embedded	B-Application
TCP/IP	B-Protocol
networking	O
stack	O
for	O
ThreadX	B-Operating_System
was	O
introduced	O
in	O
2002	O
.	O
</s>
<s>
USBX	O
–	O
the	O
embedded	B-Application
USB	B-Protocol
support	O
for	O
ThreadX	B-Operating_System
was	O
introduced	O
in	O
2004	O
.	O
</s>
<s>
ThreadX	B-Operating_System
SMP	O
for	O
SMP	O
multi-core	B-Architecture
environments	O
was	O
introduced	O
in	O
2009	O
.	O
</s>
<s>
ThreadX	B-Operating_System
Modules	O
was	O
introduced	O
in	O
2011	O
.	O
</s>
<s>
ThreadX	B-Operating_System
achieved	O
safety	O
certifications	O
for	O
:	O
TÜV	O
IEC	O
61508	O
in	O
2013	O
,	O
and	O
UL	O
60730	O
in	O
2014	O
.	O
</s>
<s>
GUIX	O
–	O
the	O
embedded	B-Application
UI	O
for	O
ThreadX	B-Operating_System
was	O
introduced	O
in	O
2014	O
.	O
</s>
<s>
Express	B-Operating_System
Logic	I-Operating_System
was	O
purchased	O
for	O
an	O
undisclosed	O
sum	O
by	O
Microsoft	O
on	O
April	O
18	O
,	O
2019	O
.	O
</s>
<s>
ThreadX	B-Operating_System
implements	O
a	O
priority-based	O
,	O
preemptive	O
scheduling	O
algorithm	O
with	O
a	O
proprietary	B-Application
feature	O
called	O
preemption-threshold	O
.	O
</s>
<s>
The	O
latter	O
has	O
been	O
shown	O
to	O
provide	O
greater	O
granularity	O
within	O
critical	O
sections	O
,	O
reduce	O
context	B-Operating_System
switches	I-Operating_System
,	O
and	O
has	O
been	O
the	O
subject	O
of	O
academic	O
research	O
on	O
guaranteeing	O
scheduling	O
.	O
</s>
<s>
ThreadX	B-Operating_System
provides	O
a	O
unique	O
construct	O
called	O
event	O
chaining	O
,	O
where	O
the	O
application	O
can	O
register	O
a	O
callback	O
function	O
on	O
all	O
application	B-Application
programming	I-Application
interfaces	I-Application
(	O
APIs	B-Application
)	O
that	O
can	O
signal	O
an	O
external	O
event	O
.	O
</s>
<s>
This	O
helps	O
applications	O
chain	O
together	O
various	O
public	O
objects	O
in	O
ThreadX	B-Operating_System
such	O
that	O
one	O
thread	B-Protocol
can	O
effectively	O
block	O
on	O
multiple	O
objects	O
.	O
</s>
<s>
ThreadX	B-Operating_System
also	O
provides	O
counting	B-Operating_System
semaphores	I-Operating_System
,	O
mutexes	B-Operating_System
with	O
optional	O
priority	B-Operating_System
inheritance	I-Operating_System
,	O
event	B-Operating_System
flags	I-Operating_System
,	O
message	B-Operating_System
queues	I-Operating_System
,	O
software	O
timers	O
,	O
fixed	O
sized	O
block	O
memory	O
,	O
and	O
variable	O
sized	O
block	O
memory	O
.	O
</s>
<s>
All	O
APIs	B-Application
in	O
ThreadX	B-Operating_System
that	O
block	O
on	O
resources	O
also	O
have	O
an	O
optional	O
timeout	O
.	O
</s>
<s>
ThreadX	B-Operating_System
offers	O
multi-core	B-Architecture
processor	I-Architecture
support	O
via	O
either	O
AMP	O
or	O
SMP	O
.	O
</s>
<s>
Application	O
code	O
isolation	O
is	O
available	O
through	O
ThreadX	B-Operating_System
Modules	O
component	O
.	O
</s>
<s>
ThreadX	B-Operating_System
RTOS	B-Operating_System
components	O
include	O
:	O
</s>
<s>
FileX	O
is	O
the	O
embedded	B-Application
file	B-Application
system	I-Application
for	O
ThreadX	B-Operating_System
.	O
</s>
<s>
FileX	O
supports	O
FAT12	B-Application
,	O
16	B-Application
,	O
32	B-Application
,	O
and	O
exFAT	B-Application
formats	O
.	O
</s>
<s>
FileX	O
also	O
offers	O
fault	O
tolerance	O
and	O
supports	O
direct	O
NOR	O
and	O
NAND	O
flash	B-Device
memory	I-Device
media	O
through	O
a	O
flash	O
wear	O
leveling	O
product	O
called	O
LevelX	O
.	O
</s>
<s>
GUIX	O
is	O
the	O
embedded	B-Application
graphical	B-Application
user	I-Application
interface	I-Application
(	O
GUI	B-Application
)	O
for	O
ThreadX	B-Operating_System
.	O
</s>
<s>
GUIX	O
provides	O
a	O
2D	O
runtime	B-Device
system	I-Device
(	O
environment	O
)	O
for	O
embedded	B-Application
applications	O
running	O
ThreadX	B-Operating_System
.	O
</s>
<s>
GUIX	O
supports	O
multiple	O
display	B-Device
devices	I-Device
with	O
a	O
variety	O
of	O
screen	O
resolutions	O
and	O
color	O
depths	O
.	O
</s>
<s>
A	O
Windows	O
WYSIWYG	B-Application
host	O
tool	O
called	O
GUIX	O
Studio	O
automatically	O
generates	O
C	B-Language
code	O
for	O
GUIX	O
to	O
execute	O
at	O
runtime	O
.	O
</s>
<s>
NetX	O
Duo	O
is	O
the	O
embedded	B-Application
TCP/IP	B-Protocol
system	O
for	O
ThreadX	B-Operating_System
.	O
</s>
<s>
NetX	O
Duo	O
supports	O
both	O
IPv4	B-Protocol
and	O
IPv6	B-Protocol
networking	O
along	O
with	O
protocols	O
such	O
as	O
ARP	O
,	O
Auto	O
IP	O
,	O
DHCP	O
,	O
DNS	O
,	O
DNS-SD	O
,	O
FTP	O
,	O
HTTP	O
,	O
ICMP	O
,	O
IGMP	O
,	O
mDNS	O
,	O
POP3	O
,	O
PPP	O
,	O
PPPoE	O
,	O
RARP	O
,	O
TFTP	O
,	O
SNTP	O
,	O
SMTP	O
,	O
SNMP	O
,	O
and	O
TELNET	O
.	O
</s>
<s>
IoT	B-Operating_System
Cloud	O
protocol	O
support	O
includes	O
CoAP	O
,	O
MQTT	O
,	O
and	O
LWM2M	O
.	O
</s>
<s>
NetX	O
Duo	O
also	O
supports	O
Thread	B-Protocol
and	O
6LoWPAN	O
.	O
</s>
<s>
In	O
2017	O
,	O
ThreadX	B-Operating_System
and	O
NetX	O
Duo	O
became	O
a	O
Thread	B-Protocol
Certified	O
Product	O
.	O
</s>
<s>
USBX	O
is	O
the	O
embedded	B-Application
Universal	O
Serial	O
Bus	O
(	O
USB	B-Protocol
)	O
system	O
for	O
ThreadX	B-Operating_System
.	O
</s>
<s>
Host	O
controller	O
support	O
includes	O
EHCI	O
,	O
OHCI	O
,	O
and	O
proprietary	B-Application
USB	B-Protocol
host	O
controllers	O
.	O
</s>
<s>
ThreadX	B-Operating_System
(	O
and	O
FileX	O
and	O
NetX	O
Duo	O
)	O
have	O
been	O
precertified	O
by	O
SGS-TÜV	O
Saar	O
to	O
the	O
following	O
safety	O
standards	O
:	O
</s>
<s>
IEC	O
61508	O
SIL	O
4	O
,	O
IEC	B-Application
62304	I-Application
Class	O
C	B-Language
,	O
ISO	O
26262	O
ASIL	O
D	O
,	O
and	O
EN	O
50128	O
SW-SIL	O
4	O
.	O
</s>
<s>
ThreadX	B-Operating_System
(	O
and	O
FileX	O
and	O
NetX	O
Duo	O
)	O
have	O
been	O
precertified	O
by	O
UL	O
to	O
the	O
following	O
safety	O
standards	O
:	O
</s>
<s>
ThreadX	B-Operating_System
has	O
also	O
been	O
certified	O
to	O
DO-178	O
standards	O
by	O
various	O
military	O
and	O
aerospace	O
companies	O
.	O
</s>
<s>
It	O
is	O
supported	O
by	O
popular	O
Transport	B-Protocol
Layer	I-Protocol
Security	I-Protocol
(	O
SSL/TLS	B-Protocol
)	O
libraries	B-Library
such	O
as	O
wolfSSL	B-Protocol
.	O
</s>
<s>
As	O
of	O
2017	O
,	O
ThreadX	B-Operating_System
is	O
packaged	O
as	O
part	O
of	O
X-Ware	O
IoT	B-Operating_System
Platform	O
in	O
full	O
source	O
code	O
and	O
with	O
no	O
runtime	O
royalty	O
payment	O
.	O
</s>
<s>
Some	O
high-profile	O
products	O
using	O
ThreadX	B-Operating_System
range	O
from	O
small	O
wearable	O
devices	O
,	O
to	O
Hewlett-Packard	O
printers	O
,	O
and	O
even	O
NASA	O
’s	O
Deep	O
Impact	O
space	O
probe	O
.	O
</s>
<s>
The	O
Raspberry	B-Operating_System
Pi	I-Operating_System
line	O
of	O
single-board	B-Device
computers	I-Device
runs	O
ThreadX	B-Operating_System
as	O
a	O
binary	O
blob	O
on	O
the	O
graphics	B-Architecture
processing	I-Architecture
unit	I-Architecture
(	O
GPU	B-Architecture
)	O
.	O
</s>
<s>
This	O
controls	O
initial	O
booting	B-Operating_System
,	O
which	O
in	O
turn	O
is	O
used	O
to	O
boot	B-Operating_System
secondary	O
operating	O
systems	O
such	O
as	O
Linux	B-Application
,	O
and	O
continues	O
to	O
operate	O
in	O
a	O
more	O
privileged	O
role	O
even	O
after	O
the	O
boot	B-Operating_System
process	I-Operating_System
.	O
</s>
