<s>
Utility	B-Operating_System
computing	I-Operating_System
or	O
The	O
Computer	B-Operating_System
Utility	I-Operating_System
is	O
a	O
service	O
provisioning	O
model	O
in	O
which	O
a	O
service	O
provider	O
makes	O
computing	B-General_Concept
resources	I-General_Concept
and	O
infrastructure	O
management	O
available	O
to	O
the	O
customer	O
as	O
needed	O
,	O
and	O
charges	O
them	O
for	O
specific	O
usage	O
rather	O
than	O
a	O
flat	O
rate	O
.	O
</s>
<s>
Like	O
other	O
types	O
of	O
on-demand	O
computing	O
(	O
such	O
as	O
grid	B-Architecture
computing	I-Architecture
)	O
,	O
the	O
utility	O
model	O
seeks	O
to	O
maximize	O
the	O
efficient	O
use	O
of	O
resources	O
and/or	O
minimize	O
associated	O
costs	O
.	O
</s>
<s>
Utility	O
is	O
the	O
packaging	O
of	O
system	B-General_Concept
resources	I-General_Concept
,	O
such	O
as	O
computation	O
,	O
storage	O
and	O
services	O
,	O
as	O
a	O
metered	O
service	O
.	O
</s>
<s>
This	O
repackaging	O
of	O
computing	O
services	O
became	O
the	O
foundation	O
of	O
the	O
shift	O
to	O
"	O
on	B-Protocol
demand	I-Protocol
"	O
computing	O
,	O
software	B-Architecture
as	I-Architecture
a	I-Architecture
service	I-Architecture
and	O
cloud	B-Architecture
computing	I-Architecture
models	O
that	O
further	O
propagated	O
the	O
idea	O
of	O
computing	O
,	O
application	O
and	O
network	O
as	O
a	O
service	O
.	O
</s>
<s>
IBM	O
,	O
HP	O
and	O
Microsoft	O
were	O
early	O
leaders	O
in	O
the	O
new	O
field	O
of	O
utility	B-Operating_System
computing	I-Operating_System
,	O
with	O
their	O
business	O
units	O
and	O
researchers	O
working	O
on	O
the	O
architecture	O
,	O
payment	O
and	O
development	O
challenges	O
of	O
the	O
new	O
computing	O
model	O
.	O
</s>
<s>
Utility	B-Operating_System
computing	I-Operating_System
can	O
support	O
grid	B-Architecture
computing	I-Architecture
which	O
has	O
the	O
characteristic	O
of	O
very	O
large	O
computations	O
or	O
sudden	O
peaks	O
in	O
demand	O
which	O
are	O
supported	O
via	O
a	O
large	O
number	O
of	O
computers	O
.	O
</s>
<s>
"	O
Utility	B-Operating_System
computing	I-Operating_System
"	O
has	O
usually	O
envisioned	O
some	O
form	O
of	O
virtualization	B-General_Concept
so	O
that	O
the	O
amount	O
of	O
storage	O
or	O
computing	O
power	O
available	O
is	O
considerably	O
larger	O
than	O
that	O
of	O
a	O
single	O
time-sharing	B-General_Concept
computer	O
.	O
</s>
<s>
These	O
might	O
be	O
a	O
dedicated	O
computer	B-Architecture
cluster	I-Architecture
specifically	O
built	O
for	O
the	O
purpose	O
of	O
being	O
rented	O
out	O
,	O
or	O
even	O
an	O
under-utilized	O
supercomputer	B-Architecture
.	O
</s>
<s>
The	O
technique	O
of	O
running	O
a	O
single	O
calculation	O
on	O
multiple	O
computers	O
is	O
known	O
as	O
distributed	B-Architecture
computing	I-Architecture
.	O
</s>
<s>
The	O
term	O
"	O
grid	B-Architecture
computing	I-Architecture
"	O
is	O
often	O
used	O
to	O
describe	O
a	O
particular	O
form	O
of	O
distributed	B-Architecture
computing	I-Architecture
,	O
where	O
the	O
supporting	O
nodes	O
are	O
geographically	O
distributed	O
or	O
cross	O
administrative	B-Protocol
domains	I-Protocol
.	O
</s>
<s>
To	O
provide	O
utility	B-Operating_System
computing	I-Operating_System
services	O
,	O
a	O
company	O
can	O
"	O
bundle	O
"	O
the	O
resources	O
of	O
members	O
of	O
the	O
public	O
for	O
sale	O
,	O
who	O
might	O
be	O
paid	O
with	O
a	O
portion	O
of	O
the	O
revenue	O
from	O
clients	O
.	O
</s>
<s>
One	O
model	O
,	O
common	O
among	O
volunteer	B-Operating_System
computing	I-Operating_System
applications	O
,	O
is	O
for	O
a	O
central	O
server	O
to	O
dispense	O
tasks	O
to	O
participating	O
nodes	O
,	O
on	O
the	O
behest	O
of	O
approved	O
end-users	O
(	O
in	O
the	O
commercial	O
case	O
,	O
the	O
paying	O
customers	O
)	O
.	O
</s>
<s>
Another	O
model	O
,	O
sometimes	O
called	O
the	O
Virtual	B-Operating_System
Organization	I-Operating_System
(	O
VO	O
)	O
,	O
is	O
more	O
decentralized	O
,	O
with	O
organizations	O
buying	O
and	O
selling	O
computing	B-General_Concept
resources	I-General_Concept
as	O
needed	O
or	O
as	O
they	O
go	O
idle	O
.	O
</s>
<s>
The	O
definition	O
of	O
"	O
utility	B-Operating_System
computing	I-Operating_System
"	O
is	O
sometimes	O
extended	O
to	O
specialized	O
tasks	O
,	O
such	O
as	O
web	O
services	O
.	O
</s>
<s>
Utility	B-Operating_System
computing	I-Operating_System
merely	O
means	O
"	O
Pay	O
and	O
Use	O
"	O
,	O
with	O
regards	O
to	O
computing	O
power	O
.	O
</s>
<s>
Utility	B-Operating_System
computing	I-Operating_System
is	O
not	O
a	O
new	O
concept	O
,	O
but	O
rather	O
has	O
quite	O
a	O
long	O
history	O
.	O
</s>
<s>
IBM	O
and	O
other	O
mainframe	O
providers	O
conducted	O
this	O
kind	O
of	O
business	O
in	O
the	O
following	O
two	O
decades	O
,	O
often	O
referred	O
to	O
as	O
time-sharing	B-General_Concept
,	O
offering	O
computing	O
power	O
and	O
database	O
storage	O
to	O
banks	O
and	O
other	O
large	O
organizations	O
from	O
their	O
worldwide	O
data	O
centers	O
.	O
</s>
<s>
In	O
the	O
late	O
1990s	O
utility	B-Operating_System
computing	I-Operating_System
re-surfaced	O
.	O
</s>
<s>
In	O
1998	O
,	O
HP	O
set	O
up	O
the	O
Utility	B-Operating_System
Computing	I-Operating_System
Division	O
in	O
Mountain	O
View	O
,	O
CA	O
,	O
assigning	O
former	O
Bell	O
Labs	O
computer	O
scientists	O
to	O
begin	O
work	O
on	O
a	O
computing	O
power	O
plant	O
,	O
incorporating	O
multiple	O
utilities	O
to	O
form	O
a	O
software	O
stack	O
.	O
</s>
<s>
HP	O
introduced	O
the	O
Utility	B-Device
Data	I-Device
Center	I-Device
in	O
2001	O
.	O
</s>
<s>
Sun	O
announced	O
the	O
Sun	B-General_Concept
Cloud	I-General_Concept
service	O
to	O
consumers	O
in	O
2000	O
.	O
</s>
<s>
In	O
December	O
2005	O
,	O
Alexa	O
launched	O
Alexa	O
Web	O
Search	O
Platform	O
,	O
a	O
Web	O
search	O
building	O
tool	O
for	O
which	O
the	O
underlying	O
power	O
is	O
utility	B-Operating_System
computing	I-Operating_System
.	O
</s>
<s>
There	O
is	O
space	O
in	O
the	O
market	O
for	O
specific	O
industries	O
and	O
applications	O
as	O
well	O
as	O
other	O
niche	O
applications	O
powered	O
by	O
utility	B-Operating_System
computing	I-Operating_System
.	O
</s>
<s>
For	O
example	O
,	O
PolyServe	O
Inc	O
.	O
offers	O
a	O
clustered	B-Application
file	I-Application
system	I-Application
based	O
on	O
commodity	O
server	O
and	O
storage	O
hardware	O
that	O
creates	O
highly	O
available	O
utility	B-Operating_System
computing	I-Operating_System
environments	O
for	O
mission-critical	O
applications	O
including	O
Oracle	O
and	O
Microsoft	O
SQL	O
Server	O
databases	O
,	O
as	O
well	O
as	O
workload	O
optimized	O
solutions	O
specifically	O
tuned	O
for	O
bulk	O
storage	O
,	O
high-performance	B-Architecture
computing	I-Architecture
,	O
vertical	O
industries	O
such	O
as	O
financial	O
services	O
,	O
seismic	O
processing	O
,	O
and	O
content	O
serving	O
.	O
</s>
<s>
In	O
spring	O
2006	O
3tera	O
announced	O
its	O
AppLogic	O
service	O
and	O
later	O
that	O
summer	O
Amazon	O
launched	O
Amazon	B-General_Concept
EC2	I-General_Concept
(	O
Elastic	B-General_Concept
Compute	I-General_Concept
Cloud	I-General_Concept
)	O
.	O
</s>
<s>
Both	O
are	O
based	O
on	O
Xen	B-Operating_System
virtualization	B-General_Concept
software	O
and	O
the	O
most	O
commonly	O
used	O
operating	O
system	O
on	O
the	O
virtual	O
computers	O
is	O
Linux	O
,	O
though	O
Windows	O
and	O
Solaris	O
are	O
supported	O
.	O
</s>
<s>
Common	O
uses	O
include	O
web	O
application	O
,	O
SaaS	B-Architecture
,	O
image	O
rendering	O
and	O
processing	O
but	O
also	O
general-purpose	O
business	O
applications	O
.	O
</s>
