<s>
Run-to-completion	B-Algorithm
scheduling	O
or	O
nonpreemptive	O
scheduling	O
is	O
a	O
scheduling	O
model	O
in	O
which	O
each	O
task	O
runs	O
until	O
it	O
either	O
finishes	O
,	O
or	O
explicitly	O
yields	O
control	O
back	O
to	O
the	O
scheduler	O
.	O
</s>
<s>
Run	B-Algorithm
to	I-Algorithm
completion	I-Algorithm
systems	O
typically	O
have	O
an	O
event	B-Operating_System
queue	I-Operating_System
which	O
is	O
serviced	O
either	O
in	O
strict	O
order	O
of	O
admission	O
by	O
an	O
event	B-General_Concept
loop	I-General_Concept
,	O
or	O
by	O
an	O
admission	O
scheduler	O
which	O
is	O
capable	O
of	O
scheduling	O
events	O
out	O
of	O
order	O
,	O
based	O
on	O
other	O
constraints	O
such	O
as	O
deadlines	O
.	O
</s>
<s>
Some	O
preemptive	O
multitasking	O
scheduling	O
systems	O
behave	O
as	O
run-to-completion	B-Algorithm
schedulers	O
in	O
regard	O
to	O
scheduling	O
tasks	O
at	O
one	O
particular	O
process	O
priority	O
level	O
,	O
at	O
the	O
same	O
time	O
as	O
those	O
processes	O
still	O
preempt	O
other	O
lower	O
priority	O
tasks	O
and	O
are	O
themselves	O
preempted	O
by	O
higher	O
priority	O
tasks	O
.	O
</s>
