<s>
A	O
software	B-Application
appliance	I-Application
is	O
a	O
software	B-Application
application	I-Application
combined	O
with	O
just	B-Operating_System
enough	I-Operating_System
operating	I-Operating_System
system	I-Operating_System
(	O
JeOS	B-Operating_System
)	O
to	O
run	O
optimally	O
on	O
industry-standard	O
hardware	O
(	O
typically	O
a	O
server	O
)	O
or	O
in	O
a	O
virtual	B-Architecture
machine	I-Architecture
.	O
</s>
<s>
It	O
is	O
a	O
software	B-Application
distribution	I-Application
or	O
firmware	O
that	O
implements	O
a	O
computer	B-Architecture
appliance	I-Architecture
.	O
</s>
<s>
Virtual	B-Application
appliances	I-Application
are	O
a	O
subset	O
of	O
software	B-Application
appliances	I-Application
.	O
</s>
<s>
A	O
virtual	B-Application
appliance	I-Application
is	O
a	O
virtual	B-Architecture
machine	I-Architecture
image	O
designed	O
to	O
run	O
on	O
a	O
specific	O
virtualization	B-General_Concept
platform	I-General_Concept
,	O
while	O
a	O
software	B-Application
appliance	I-Application
is	O
often	O
packaged	O
in	O
more	O
generally	O
applicable	O
image	O
format	O
(	O
e.g.	O
,	O
Live	O
CD	O
)	O
that	O
supports	O
installations	O
to	O
physical	O
machines	O
and	O
multiple	O
types	O
of	O
virtual	B-Architecture
machines	I-Architecture
.	O
</s>
<s>
Installing	O
a	O
software	B-Application
appliance	I-Application
to	O
a	O
virtual	B-Architecture
machine	I-Architecture
and	O
packaging	O
that	O
into	O
an	O
image	O
,	O
creates	O
a	O
virtual	B-Application
appliance	I-Application
.	O
</s>
<s>
Software	B-Application
appliances	I-Application
have	O
several	O
benefits	O
over	O
traditional	O
software	B-Application
applications	I-Application
that	O
are	O
installed	O
on	O
top	O
of	O
an	O
operating	B-General_Concept
system	I-General_Concept
:	O
</s>
<s>
Simplified	O
deployment	O
:	O
A	O
software	B-Application
appliance	I-Application
encapsulates	O
an	O
application	O
's	O
dependencies	O
in	O
a	O
pre-integrated	O
,	O
self-contained	O
unit	O
.	O
</s>
<s>
This	O
can	O
dramatically	O
simplify	O
software	O
deployment	O
by	O
freeing	O
users	O
from	O
having	O
to	O
worry	O
about	O
resolving	O
potentially	B-Protocol
complex	I-Protocol
OS	O
compatibility	O
issues	O
,	O
library	O
dependencies	O
or	O
undesirable	O
interactions	O
with	O
other	O
applications	O
.	O
</s>
<s>
This	O
is	O
known	O
as	O
a	O
"	O
toaster.	O
"	O
</s>
<s>
Improved	O
isolation	O
:	O
software	B-Application
appliances	I-Application
are	O
typically	O
used	O
to	O
run	O
applications	O
in	O
isolation	O
from	O
one	O
another	O
.	O
</s>
<s>
Improved	O
performance	O
:	O
A	O
software	B-Application
appliance	I-Application
does	O
not	O
embed	O
any	O
unused	O
operating	B-General_Concept
system	I-General_Concept
services	O
,	O
applications	O
or	O
any	O
form	O
of	O
bloatware	O
hence	O
it	O
does	O
not	O
have	O
to	O
share	O
the	O
hardware	O
resources	O
(	O
CPU	O
,	O
memory	O
,	O
storage	O
space	O
,	O
...	O
)	O
usually	O
consumed	O
by	O
these	O
on	O
a	O
generic	O
OS	O
setup	O
.	O
</s>
<s>
In	O
the	O
case	O
where	O
multiple	O
software	B-Application
appliances	I-Application
share	O
and	O
run	O
simultaneously	O
on	O
the	O
same	O
hardware	O
(	O
on	O
a	O
virtualization	B-General_Concept
platform	I-General_Concept
for	O
example	O
)	O
this	O
will	O
not	O
hold	O
true	O
as	O
running	O
n	O
instances	O
of	O
a	O
software	B-Application
appliance	I-Application
(	O
OS	O
+	O
software	B-Application
application	I-Application
)	O
will	O
consume	O
more	O
hardware	O
resources	O
than	O
running	O
n	O
instances	O
of	O
a	O
software	B-Application
application	I-Application
on	O
1	O
instance	O
of	O
an	O
operating	B-General_Concept
system	I-General_Concept
due	O
to	O
the	O
overhead	O
of	O
running	O
n	O
-	O
1	O
more	O
instances	O
of	O
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
A	O
software	B-Application
appliance	I-Application
can	O
be	O
packaged	O
in	O
a	O
virtual	B-Architecture
machine	I-Architecture
format	O
as	O
a	O
virtual	B-Application
appliance	I-Application
,	O
allowing	O
it	O
to	O
be	O
run	O
within	O
a	O
virtual	B-Architecture
machine	I-Architecture
container	B-Application
.	O
</s>
<s>
A	O
virtual	B-Application
appliance	I-Application
could	O
be	O
built	O
using	O
either	O
a	O
standard	O
virtual	B-Architecture
machine	I-Architecture
format	O
such	O
as	O
Open	O
Virtualization	O
Format	O
(	O
OVF	O
)	O
,	O
or	O
a	O
format	O
specific	O
to	O
a	O
particular	O
virtual	B-Architecture
machine	I-Architecture
container	B-Application
(	O
for	O
example	O
,	O
VMware	O
,	O
VirtualBox	O
,	O
or	O
Amazon	O
EC2	O
)	O
.	O
</s>
<s>
Containers	B-Application
and	O
their	O
images	O
(	O
such	O
as	O
those	O
provided	O
by	O
Docker	B-Language
and	O
Docker	B-Language
Hub	O
)	O
can	O
be	O
seen	O
as	O
an	O
implementation	O
of	O
software	B-Application
appliances	I-Application
.	O
</s>
<s>
A	O
software	B-Application
appliance	I-Application
can	O
be	O
packaged	O
as	O
a	O
Live	O
CD	O
image	O
,	O
allowing	O
it	O
to	O
run	O
on	O
real	O
hardware	O
in	O
addition	O
to	O
most	O
types	O
of	O
virtual	B-Architecture
machines	I-Architecture
.	O
</s>
<s>
This	O
allows	O
developers	O
to	O
avoid	O
the	O
complexities	O
involved	O
in	O
supporting	O
multiple	O
incompatible	O
virtual	B-Architecture
machine	I-Architecture
image	O
formats	O
and	O
focus	O
on	O
the	O
lowest	O
common	O
denominator	O
instead	O
(	O
i.e.	O
,	O
ISO	O
images	O
are	O
supported	O
by	O
most	O
Virtual	B-Architecture
Machine	I-Architecture
platforms	O
)	O
.	O
</s>
<s>
(	O
pay-as-you-go	O
)	O
and	O
are	O
an	O
alternative	O
approach	O
to	O
software	B-Architecture
as	I-Architecture
a	I-Architecture
service	I-Architecture
.	O
</s>
<s>
In	O
some	O
cases	O
,	O
the	O
application	O
vendor	O
may	O
install	O
the	O
software	B-Application
appliance	I-Application
on	O
a	O
piece	O
of	O
hardware	O
prior	O
to	O
delivery	O
to	O
the	O
customer	O
,	O
thereby	O
creating	O
a	O
computer	B-Architecture
appliance	I-Architecture
.	O
</s>
