<s>
Small	B-Device
form	I-Device
factor	I-Device
(	O
abbreviated	O
:	O
SFF	O
or	O
SFX	O
)	O
is	O
a	O
term	O
used	O
for	O
desktop	B-Device
computers	I-Device
and	O
for	O
some	O
of	O
its	O
components	O
,	O
gabinet	B-Application
and	O
motherboard	B-Device
,	O
to	O
indicate	O
that	O
they	O
are	O
designed	O
in	O
accordance	O
with	O
one	O
of	O
several	O
standardized	O
computer	O
form	O
factors	O
intended	O
to	O
minimize	O
the	O
volume	O
and	O
footprint	O
of	O
a	O
desktop	B-Device
computer	I-Device
compared	O
to	O
the	O
standard	O
ATX	B-Language
form	O
factor	O
(	O
industrial	O
designer	O
pattern	O
)	O
.	O
</s>
<s>
Their	O
smaller	O
and	O
often	O
lighter	O
construction	O
has	O
made	O
them	O
popular	O
as	O
home	O
theater	O
PCs	O
and	O
as	O
gaming	B-Device
computers	I-Device
for	O
attending	O
LAN	O
parties	O
.	O
</s>
<s>
Small	B-Device
form	I-Device
factors	I-Device
do	O
not	O
include	O
computing	O
devices	O
that	O
have	O
traditionally	O
been	O
small	O
,	O
such	O
as	O
embedded	B-Architecture
or	O
mobile	O
systems	O
.	O
</s>
<s>
However	O
,	O
"	O
small	B-Device
form	I-Device
factor	I-Device
"	O
lacks	O
a	O
normative	O
definition	O
and	O
is	O
consequently	O
open	O
to	O
interpretation	O
and	O
misuse	O
.	O
</s>
<s>
According	O
to	O
marketing	O
strategy	O
,	O
one	O
manufacturer	O
may	O
decide	O
to	O
mark	O
their	O
product	O
as	O
"	O
small	B-Device
form	I-Device
factor	I-Device
"	O
while	O
other	O
manufacturers	O
are	O
using	O
different	O
marketing	O
name	O
(	O
such	O
as	O
"	O
Minitower	O
"	O
,	O
"	O
Microtower	O
"	O
or	O
"	O
Desktop	O
"	O
)	O
for	O
personal	O
computers	O
of	O
similar	O
or	O
even	O
smaller	O
footprint	O
.	O
</s>
<s>
The	O
acronym	O
SFF	O
originally	O
stood	O
for	O
"	O
Shuttle	O
Form	O
Factor	O
,	O
"	O
describing	O
shoebox-sized	O
personal	O
computers	O
with	O
two	O
expansion	B-Device
slots	I-Device
.	O
</s>
<s>
SFF	O
originally	O
referred	O
to	O
systems	O
smaller	O
than	O
the	O
Micro-ATX	B-Device
.	O
</s>
<s>
Small	B-Device
form	I-Device
factor	I-Device
computers	O
are	O
generally	O
designed	O
to	O
support	O
the	O
same	O
features	O
as	O
modern	O
desktop	B-Device
computers	I-Device
,	O
but	O
in	O
a	O
smaller	O
space	O
.	O
</s>
<s>
Most	O
accept	O
standard	O
x86	B-Operating_System
microprocessors	I-Operating_System
,	O
standard	O
DIMM	B-General_Concept
memory	O
modules	O
,	O
standard	O
8.9cm	O
(	O
3.5	O
"	O
)	O
hard	B-Device
disks	I-Device
,	O
and	O
standard	O
13.3cm	O
(	O
5.25	O
"	O
)	O
optical	O
drives	O
.	O
</s>
<s>
However	O
,	O
the	O
small	O
size	O
of	O
SFF	O
cases	O
may	O
limit	O
expansion	O
options	O
;	O
many	O
commercial	O
offerings	O
provide	O
only	O
one	O
8.9cm	O
(	O
3.5	O
"	O
)	O
drive	B-Device
bay	I-Device
and	O
one	O
or	O
two	O
13.3cm	O
(	O
5.25	O
"	O
)	O
external	O
bays	O
.	O
</s>
<s>
Standard	O
CPU	B-Device
heatsinks	O
do	O
not	O
always	O
fit	O
inside	O
an	O
SFF	O
computer	O
,	O
so	O
some	O
manufacturers	O
provide	O
custom	O
cooling	B-General_Concept
systems	O
.	O
</s>
<s>
Though	O
limited	O
to	O
one	O
or	O
two	O
expansion	B-Device
cards	I-Device
,	O
a	O
few	O
have	O
the	O
space	O
for	O
-length	O
cards	O
such	O
as	O
the	O
GeForce	O
GTX-295	O
.	O
</s>
<s>
Most	O
SFF	O
computers	O
use	O
highly	O
integrated	O
motherboards	B-Device
containing	O
many	O
on-board	O
peripherals	O
,	O
reducing	O
the	O
need	O
for	O
expansion	B-Device
cards	I-Device
.	O
</s>
<s>
As	O
of	O
2020	O
many	O
SFF	O
PC	O
cases	O
do	O
not	O
include	O
any	O
expansion	O
bays	O
larger	O
than	O
2.5	O
inches	O
(	O
large	O
enough	O
to	O
accommodate	O
SATA	O
SSDs	O
)	O
,	O
due	O
to	O
the	O
declining	O
popularity	O
of	O
optical	O
disc	O
drives	O
and	O
3.5	O
inch	O
hard	B-Device
drives	I-Device
in	O
the	O
consumer	O
space	O
.	O
</s>
<s>
Even	O
if	O
labeled	O
"	O
SFF	O
,	O
"	O
cube-style	O
cases	O
that	O
support	O
full-sized	O
(	O
PS2	O
form	O
factor	O
)	O
power	O
supplies	O
actually	O
have	O
a	O
microATX	B-Device
form	O
factor	O
.	O
</s>
<s>
Some	O
SFF	O
computers	O
even	O
include	O
compact	O
components	O
designed	O
for	O
mobile	O
computers	O
,	O
such	O
as	O
notebook	O
optical	O
drives	O
,	O
notebook	O
memory	O
modules	O
,	O
notebook	O
processors	O
,	O
and	O
external	O
AC	O
adapters	O
,	O
rather	O
than	O
the	O
internal	O
power	O
supply	O
units	O
found	O
in	O
full-size	O
desktop	B-Device
computers	I-Device
.	O
</s>
<s>
Crowdfunding	O
and	O
availability	O
of	O
rapid	O
prototyping	O
tools	O
has	O
enabled	O
the	O
production	O
of	O
several	O
mini-ITX	B-Architecture
cases	O
focusing	O
on	O
efficiently	O
organizing	O
commercial	O
computer	O
components	O
into	O
small	O
volumes	O
including	O
the	O
Ghost	O
S1	O
,	O
DAN	O
A4-SFX	O
,	O
and	O
Thor	O
Zone	O
MJOLNIR	O
.	O
</s>
<s>
Smaller	O
models	O
are	O
typically	O
sold	O
as	O
barebones	B-Device
units	O
,	O
including	O
a	O
case	O
,	O
motherboard	B-Device
,	O
and	O
power	O
supply	O
designed	O
to	O
fit	O
together	O
.	O
</s>
<s>
The	O
motherboard	B-Device
lies	O
flat	O
against	O
the	O
base	O
of	O
the	O
case	O
.	O
</s>
<s>
Upgrade	O
options	O
may	O
be	O
limited	O
by	O
the	O
non-standard	O
motherboards	B-Device
,	O
cramped	O
interior	O
space	O
,	O
and	O
power	O
and	O
airflow	O
concerns	O
.	O
</s>
<s>
The	O
Power	B-Device
Mac	I-Device
G4	I-Device
Cube	I-Device
,	O
released	O
in	O
2000	O
,	O
and	O
the	O
Shuttle	O
XPC	O
are	O
good	O
examples	O
of	O
this	O
design	O
.	O
</s>
<s>
Shuttle	O
has	O
adapted	O
several	O
of	O
its	O
XPC	O
models	O
(	O
some	O
5-series	O
and	O
most	O
later	O
)	O
to	O
alternately	O
accept	O
mini-ITX	B-Architecture
motherboards	B-Device
.	O
</s>
<s>
The	O
base	O
of	O
the	O
XPC	O
is	O
provided	O
with	O
mounting	O
points	O
which	O
accommodate	O
both	O
"	O
Shuttle	O
form	O
factor	O
"	O
(	O
ShFF	O
)	O
and	O
mini-ITX	B-Architecture
motherboards	B-Device
.	O
</s>
<s>
In	O
order	O
to	O
accommodate	O
mini-ITX	B-Architecture
motherboards	B-Device
,	O
two	O
of	O
the	O
ShFF	O
mounting	O
points	O
are	O
simply	O
relocated	O
(	O
the	O
remaining	O
mini-ITX	B-Architecture
mounting	O
points	O
are	O
in	O
common	O
with	O
the	O
remaining	O
ShFF	O
mounting	O
points	O
)	O
.	O
</s>
<s>
A	O
"	O
standard	O
"	O
ShFF	O
motherboard	B-Device
is	O
20.6cm	O
(	O
81/8	O
″	O
)	O
wide	O
by	O
27.3cm	O
(	O
103/4	O
″	O
)	O
deep	O
,	O
with	O
the	O
I/O	O
shield	O
and	O
the	O
two	O
PCI	O
slots	O
being	O
located	O
in	O
common	O
with	O
mini-ITX	B-Architecture
motherboards	B-Device
.	O
</s>
<s>
Most	O
ShFF	O
systems	O
utilize	O
Shuttle	O
's	O
proprietary	O
heat	O
pipe	O
(	O
liquid	O
cooling	B-General_Concept
)	O
system	O
,	O
"	O
Integrated	O
Cooling	B-General_Concept
Engine	O
"	O
(	O
ICE	O
)	O
,	O
for	O
the	O
processor	O
,	O
although	O
several	O
also	O
feature	O
heat	O
pipe	O
cooling	B-General_Concept
for	O
the	O
voltage	O
regulator	O
and/or	O
the	O
chip	O
set	O
(	O
Northbridge	B-Device
)	O
.	O
</s>
<s>
When	O
an	O
ShFF	O
system	O
is	O
upgraded	O
to	O
a	O
mini-ITX	B-Architecture
motherboard	B-Device
,	O
an	O
Intel	O
or	O
compatible	O
processor	O
fan	O
must	O
replace	O
the	O
ICE	O
cooler	O
.	O
</s>
<s>
The	O
ShFF	O
's	O
ICE	O
computer	B-Application
fan	I-Application
is	O
so	O
designed	O
that	O
it	O
may	O
be	O
repurposed	O
as	O
a	O
case	B-Application
fan	I-Application
when	O
the	O
case	O
is	O
upgraded	O
to	O
mini-ITX	B-Architecture
use	O
.	O
</s>
<s>
When	O
so	O
upgraded	O
,	O
the	O
repurposed	O
fan	O
would	O
be	O
connected	O
to	O
the	O
motherboard	B-Device
's	O
case	B-Application
fan	I-Application
connector	O
(	O
3-pin	O
)	O
while	O
the	O
new	O
CPU	B-Application
fan	I-Application
would	O
be	O
connected	O
to	O
the	O
motherboard	B-Device
's	O
CPU	B-Application
fan	I-Application
connector	O
(	O
4-pin	O
)	O
.	O
</s>
<s>
These	O
layers	O
can	O
be	O
for	O
add-on	B-Device
cards	I-Device
,	O
optical	O
drives	O
,	O
and	O
hard	B-Device
drives	I-Device
,	O
using	O
either	O
internal	O
power	O
supplies	O
or	O
external	O
AC	O
adapter	O
power	O
sources	O
.	O
</s>
<s>
After	O
the	O
S120	O
,	O
AOpen	O
made	O
more	O
small	B-Device
form	I-Device
factor	I-Device
cases	O
for	O
systems	O
with	O
Micro	B-Device
ATX	I-Device
and	O
Mini-ITX	B-Architecture
.	O
</s>
<s>
Until	O
2005	O
,	O
SFF	O
cases	O
were	O
usually	O
sold	O
as	O
barebones	B-Device
units	O
(	O
case	O
,	O
power	O
supply	O
,	O
and	O
motherboard	B-Device
)	O
to	O
system	O
integrators	O
and	O
home-based	O
builders	O
.	O
</s>
<s>
In	O
2005	O
,	O
Apple	O
Inc	O
.	O
introduced	O
its	O
Mac	B-Device
Mini	I-Device
(	O
volume	O
of	O
1.4	O
L	O
,	O
excluding	O
external	O
power	O
brick	O
)	O
.	O
</s>
<s>
Later	O
in	O
the	O
same	O
year	O
,	O
the	O
first	O
AOpen	O
mini	B-Protocol
PC	I-Protocol
MP915	O
(	O
renamed	O
to	O
XC	O
mini	O
in	O
2007	O
since	O
"	O
mini	B-Protocol
PC	I-Protocol
"	O
could	O
not	O
be	O
registered	O
as	O
a	O
trademark	O
)	O
,	O
was	O
announced	O
.	O
</s>
<s>
The	O
size	O
of	O
the	O
XC	O
mini	O
series	O
PC	O
—	O
16.5(W )	O
×	O
5.0(H )	O
×	O
16.5(D )	O
cm	O
—	O
makes	O
it	O
one	O
of	O
the	O
smallest	O
desktop	B-Device
PC	I-Device
systems	O
(	O
1.3L	O
volume	O
)	O
.	O
</s>
<s>
It	O
was	O
criticized	O
for	O
looking	O
like	O
the	O
Apple	B-Device
Mac	I-Device
Mini	I-Device
but	O
Apple	O
has	O
not	O
taken	O
action	O
on	O
this	O
subject	O
.	O
</s>
<s>
In	O
February	O
2007	O
,	O
AOpen	O
redesigned	O
the	O
case	O
of	O
the	O
mini	B-Protocol
PC	I-Protocol
MP945	O
series	O
.	O
</s>
<s>
These	O
are	O
often	O
described	O
as	O
bookshelf	O
units	O
since	O
they	O
resemble	O
a	O
miniature	O
tower	B-General_Concept
case	I-General_Concept
small	O
enough	O
to	O
fit	O
on	O
a	O
bookshelf	O
.	O
</s>
<s>
The	O
HP	O
Slimline	O
uses	O
a	O
non-standard	O
motherboard	B-Device
that	O
is	O
very	O
similar	O
in	O
size	O
to	O
Mini-ITX	B-Architecture
.	O
</s>
<s>
In	O
addition	O
to	O
its	O
industrial	O
use	O
,	O
the	O
extremely	O
small	O
Mini-ITX	B-Architecture
motherboard	B-Device
form	O
factor	O
has	O
also	O
been	O
incorporated	O
into	O
SFF	O
computers	O
.	O
</s>
<s>
These	O
are	O
often	O
extremely	O
compact	O
,	O
incorporating	O
low-power	O
components	O
such	O
as	O
the	O
VIA	B-Device
C3	I-Device
processors	O
.	O
</s>
<s>
At	O
17.8	O
x	O
25.4	O
x	O
5.1cm	O
(	O
7	O
×	O
10	O
×	O
2	O
"	O
)	O
the	O
Travla	O
C134	O
is	O
somewhat	O
larger	O
than	O
the	O
Mac	B-Device
mini	I-Device
which	O
is	O
16.5	O
x	O
16.5	O
x	O
5.1cm	O
(	O
6.5	O
×	O
6.5	O
×	O
2	O
"	O
)	O
and	O
barely	O
bigger	O
than	O
a	O
standard	O
13.3cm	O
(	O
5.25	O
"	O
)	O
optical	O
drive	O
.	O
</s>
<s>
These	O
include	O
the	O
Zonbu	B-Application
,	O
fit-PC	B-Application
,	O
Linutop	B-Application
,	O
and	O
A9home	B-Device
.	O
</s>
<s>
With	O
the	O
release	O
of	O
Intel	B-Device
Atom	I-Device
CPU	I-Device
,	O
AOpen	O
also	O
made	O
Nettop	B-Protocol
systems	O
:	O
the	O
uBox	O
series	O
with	O
model	O
LE200	O
and	O
LE210	O
.	O
</s>
<s>
The	O
uBox	O
series	O
equips	O
a	O
dual	O
core	O
Intel	B-Device
Atom	I-Device
270/330	O
processor	O
,	O
single	O
channel	O
DDR-II	O
533/667	O
memory	O
,	O
Intel	O
945GC+ICH7	O
chipset	O
,	O
three	O
SATA	O
connectors	O
and	O
5.1	O
channel	O
high	O
definition	O
audio	O
output	O
.	O
</s>
<s>
Essentially	O
a	O
bookshelf-style	O
case	O
lying	O
on	O
its	O
side	O
,	O
a	O
miniature	O
HTPC	O
replicates	O
the	O
look	O
of	O
other	O
smaller-than-rack-sized	O
home	O
theatre	O
components	O
such	O
as	O
a	O
DVR	B-Application
or	O
mini	O
audio	O
receiver	O
.	O
</s>
<s>
The	O
front	O
panel	O
interface	O
is	O
emphasized	O
,	O
with	O
the	O
optical	O
disc	O
drive	O
rotated	O
relative	O
to	O
the	O
case	O
in	O
order	O
to	O
maintain	O
horizontal	O
mounting	O
,	O
and	O
more	O
motherboard	B-Device
port	O
connectors	O
(	O
such	O
as	O
for	O
USB	B-Protocol
)	O
are	O
routed	O
to	O
the	O
front	O
panel	O
,	O
they	O
normally	O
are	O
as	O
powerful	O
as	O
PC	O
desktops	O
.	O
</s>
<s>
A	O
computer-on-module	B-Application
(	O
COM	O
)	O
is	O
a	O
complete	O
computer	O
built	O
on	O
a	O
single	O
circuit	O
board	O
.	O
</s>
<s>
They	O
are	O
often	O
used	O
as	O
embedded	B-Architecture
systems	I-Architecture
due	O
to	O
their	O
small	O
physical	O
size	O
and	O
low	O
power	O
consumption	O
.	O
</s>
<s>
Gumstix	B-Application
is	O
one	O
manufacturer	O
of	O
COMs	O
.	O
</s>
<s>
Each	O
model	O
of	O
Dell	O
's	O
OptiPlex	B-Device
line	O
of	O
computers	O
typically	O
includes	O
an	O
Ultra-Small	O
Form	O
Factor	O
(	O
USFF	O
)	O
chassis	O
option	O
.	O
</s>
<s>
In	O
the	O
Core	B-Device
2	I-Device
era	O
,	O
these	O
machines	O
used	O
8.9cm	O
(	O
3.5	O
"	O
)	O
desktop	O
hard	B-Device
drives	I-Device
and	O
external	O
power	O
supplies	O
,	O
such	O
as	O
the	O
OptiPlex	B-Device
745	O
and	O
755	O
.	O
</s>
<s>
More	O
recent	O
units	O
use	O
6.4cm	O
(	O
2.5	O
"	O
)	O
laptop	B-Device
hard	I-Device
drives	I-Device
and	O
have	O
integrated	O
power	O
supplies	O
,	O
such	O
as	O
the	O
OptiPlex	B-Device
990	O
USFF	O
.	O
</s>
<s>
The	O
compact	O
size	O
comes	O
at	O
the	O
cost	O
of	O
restricted	O
expandability	O
,	O
as	O
USFF	O
models	O
have	O
no	O
PCI	O
or	O
PCIe	O
slots	O
and	O
may	O
have	O
limited	O
CPU	B-Device
and	O
memory	O
options	O
.	O
</s>
<s>
Understood	O
as	O
comprising	O
nano-ITX	B-Device
(	O
12	O
×	O
12cm	O
)	O
and	O
pico-ITX	B-Device
(	O
10	O
×	O
7.2cm	O
)	O
boards	O
,	O
the	O
format	O
was	O
championed	O
by	O
VIA	O
Technologies	O
.	O
</s>
<s>
Intel	O
now	O
describes	O
its	O
own	O
Next	B-Device
Unit	I-Device
of	I-Device
Computing	I-Device
(	O
NUC	O
)	O
products	O
(	O
10.2	O
x	O
10.2cm	O
or	O
4	O
×	O
4	O
"	O
)	O
as	O
UCFF	O
.	O
</s>
