<s>
In	O
computing	O
,	O
an	O
alien	B-Operating_System
thread	I-Operating_System
in	O
a	O
multi-processor	B-Operating_System
system	O
is	O
a	O
thread	B-Operating_System
of	O
program	O
execution	O
executed	O
by	O
one	O
processor	O
on	O
behalf	O
of	O
a	O
process	O
running	O
on	O
another	O
processor	O
.	O
</s>
<s>
Alien	B-Operating_System
threads	I-Operating_System
are	O
implemented	O
in	O
the	O
Fiasco.OC/L4	O
microkernel	O
operating	O
system	O
.	O
</s>
