<s>
Run-Time	B-Device
Abstraction	I-Device
Services	I-Device
(	O
RTAS	O
)	O
is	O
run-time	O
firmware	B-Application
that	O
provides	O
abstraction	O
to	O
the	O
operating	B-General_Concept
systems	I-General_Concept
running	O
on	O
IBM	B-Device
System	I-Device
i	I-Device
and	O
IBM	B-Device
System	I-Device
p	I-Device
computers	O
.	O
</s>
<s>
It	O
contrasts	O
with	O
Open	B-Architecture
Firmware	I-Architecture
,	O
in	O
that	O
the	O
latter	O
is	O
usually	O
used	O
only	O
during	O
boot	O
,	O
while	O
RTAS	O
is	O
used	O
during	O
run-time	O
.	O
</s>
