<s>
In	O
computing	O
and	O
parallel	B-Operating_System
processing	I-Operating_System
,	O
memory	B-General_Concept
semantics	I-General_Concept
refers	O
to	O
the	O
process	O
logic	O
used	O
to	O
control	O
access	O
to	O
shared	B-Operating_System
memory	I-Operating_System
locations	O
,	O
or	O
at	O
a	O
higher	O
level	O
to	O
shared	O
variables	O
in	O
the	O
presence	O
of	O
multiple	O
threads	O
or	O
processors	O
.	O
</s>
<s>
Memory	B-General_Concept
semantics	I-General_Concept
may	O
also	O
be	O
defined	O
for	O
transactional	B-Operating_System
memory	I-Operating_System
,	O
where	O
issues	O
related	O
to	O
the	O
interaction	O
of	O
transactions	O
and	O
locks	B-Operating_System
,	O
and	O
user-level	O
actions	O
need	O
to	O
be	O
defined	O
and	O
specified	O
.	O
</s>
