<s>
Cross-platform	B-General_Concept
virtualization	I-General_Concept
is	O
a	O
form	O
of	O
computer	B-General_Concept
virtualization	I-General_Concept
that	O
allows	O
software	O
compiled	O
for	O
a	O
specific	O
instruction	B-General_Concept
set	I-General_Concept
and	O
operating	B-General_Concept
system	I-General_Concept
to	O
run	O
unmodified	O
on	O
computers	O
with	O
different	O
CPUs	O
and/or	O
operating	B-General_Concept
systems	I-General_Concept
,	O
through	O
a	O
combination	O
of	O
dynamic	O
binary	O
translation	O
and	O
operating	B-General_Concept
system	I-General_Concept
call	O
mapping	O
.	O
</s>
<s>
Since	O
the	O
software	O
runs	O
on	O
a	O
virtualized	B-General_Concept
equivalent	O
of	O
the	O
original	O
computer	O
,	O
it	O
does	O
not	O
require	O
recompilation	O
or	O
porting	O
,	O
thus	O
saving	O
time	O
and	O
development	O
resources	O
.	O
</s>
<s>
For	O
this	O
reason	O
,	O
cross-platform	B-General_Concept
virtualization	I-General_Concept
may	O
be	O
used	O
as	O
a	O
temporary	O
solution	O
until	O
resources	O
are	O
available	O
to	O
port	O
the	O
software	O
.	O
</s>
<s>
Alternatively	O
,	O
cross-platform	B-General_Concept
virtualization	I-General_Concept
may	O
be	O
used	O
to	O
support	O
legacy	O
code	O
,	O
which	O
running	O
on	O
a	O
newer	O
and	O
faster	O
machine	O
still	O
maintains	O
adequate	O
performance	O
even	O
with	O
virtualization	B-General_Concept
overhead	O
.	O
</s>
<s>
By	O
creating	O
an	O
abstraction	B-Architecture
layer	I-Architecture
capable	O
of	O
running	O
software	O
compiled	O
for	O
a	O
different	O
computer	O
system	O
,	O
cross-platform	B-General_Concept
virtualization	I-General_Concept
characterizes	O
the	O
Popek	B-Architecture
and	I-Architecture
Goldberg	I-Architecture
virtualization	I-Architecture
requirements	I-Architecture
outlined	O
by	O
Gerald	O
J	O
.	O
Popek	O
and	O
Robert	O
P	O
.	O
Goldberg	O
in	O
their	O
1974	O
article	O
"	O
Formal	O
Requirements	O
for	O
Virtualizable	O
Third	O
Generation	O
Architectures	O
"	O
.	O
</s>
<s>
Cross-platform	B-General_Concept
virtualization	I-General_Concept
is	O
distinct	O
from	O
simple	O
emulation	B-Application
and	O
binary	O
translation	O
-	O
which	O
involve	O
the	O
direct	O
translation	O
of	O
one	O
instruction	B-General_Concept
set	I-General_Concept
to	O
another	O
-	O
since	O
the	O
inclusion	O
of	O
operating	B-General_Concept
system	I-General_Concept
call	O
mapping	O
provides	O
a	O
more	O
complete	O
virtualized	B-General_Concept
environment	O
.	O
</s>
<s>
Cross-platform	B-General_Concept
virtualization	I-General_Concept
is	O
also	O
complementary	O
to	O
server	B-General_Concept
virtualization	I-General_Concept
and	O
desktop	B-Protocol
virtualization	I-Protocol
solutions	O
,	O
since	O
these	O
are	O
typically	O
constrained	O
to	O
a	O
single	O
instruction	B-General_Concept
set	I-General_Concept
,	O
such	O
as	O
x86	B-Operating_System
or	O
Power	B-Architecture
ISA	I-Architecture
.	O
</s>
<s>
Modern	O
variants	O
of	O
cross-platform	B-Operating_System
virtualisation	B-General_Concept
may	O
employ	O
hardware	O
acceleration	O
techniques	O
to	O
offset	O
some	O
of	O
the	O
cost	O
incurred	O
in	O
the	O
guest-to-host	O
system	O
translation	O
.	O
</s>
