<s>
U3	B-Application
was	O
a	O
joint	O
venture	O
between	O
SanDisk	O
and	O
M-Systems	O
,	O
producing	O
a	O
proprietary	B-Application
method	O
of	O
launching	O
Windows	B-Application
software	O
from	O
special	O
USB	O
flash	O
drives	O
.	O
</s>
<s>
Flash	O
drives	O
adhering	O
to	O
the	O
U3	B-Application
specification	O
are	O
termed	O
"	O
U3	B-Application
smart	I-Application
drives	I-Application
"	O
.	O
</s>
<s>
U3	B-Application
smart	I-Application
drives	I-Application
come	O
preinstalled	O
with	O
the	O
U3	B-Application
Launchpad	I-Application
.	O
</s>
<s>
Applications	O
that	O
comply	O
with	O
U3	B-Application
specifications	O
are	O
allowed	O
to	O
write	O
files	B-Operating_System
or	O
registry	B-Protocol
information	O
to	O
the	O
host	O
computer	B-General_Concept
,	O
but	O
they	O
must	O
remove	O
this	O
information	O
when	O
the	O
flash	O
drive	O
is	O
ejected	O
.	O
</s>
<s>
Microsoft	O
and	O
SanDisk	O
created	O
a	O
successor	O
called	O
StartKey	B-Device
.	O
</s>
<s>
SanDisk	O
began	O
phasing	O
out	O
support	O
for	O
U3	B-Application
Technology	O
in	O
late	O
2009	O
.	O
</s>
<s>
A	O
U3	B-Application
flash	O
drive	O
presents	O
itself	O
to	O
the	O
host	O
system	O
as	O
a	O
USB	O
hub	O
with	O
a	O
CD	O
drive	O
and	O
standard	O
USB	B-Architecture
mass	I-Architecture
storage	I-Architecture
device	I-Architecture
attached	O
.	O
</s>
<s>
This	O
configuration	O
causes	O
Windows	B-Application
disk	O
management	O
to	O
show	O
two	O
drives	O
:	O
</s>
<s>
A	O
read-only	O
ISO	B-Application
9660	I-Application
volume	O
on	O
an	O
emulated	O
CD-ROM	O
drive	O
with	O
an	O
autorun	O
configuration	O
to	O
execute	O
the	O
U3	B-Application
LaunchPad	I-Application
,	O
and	O
;	O
</s>
<s>
A	O
standard	O
flash	O
drive	O
(	O
FAT	B-Application
formatted	O
)	O
that	O
includes	O
a	O
hidden	O
"	O
SYSTEM	O
"	O
folder	O
with	O
installed	O
applications	O
.	O
</s>
<s>
U3	B-Application
compliant	O
applications	O
can	O
be	O
(	O
optionally	O
)	O
preloaded	O
by	O
manufacturers	O
.	O
</s>
<s>
The	O
U3	B-Application
Launchpad	I-Application
(	O
LaunchU3.exe	O
)	O
is	O
a	O
Windows	B-Application
program	O
manager	O
that	O
is	O
preinstalled	O
on	O
every	O
U3	B-Application
smart	I-Application
drive	I-Application
.	O
</s>
<s>
The	O
U3	B-Application
Launchpad	I-Application
automatically	O
starts	O
at	O
insertion	O
of	O
a	O
U3	B-Application
enabled	O
device	O
.	O
</s>
<s>
To	O
be	O
fully	O
U3	B-Application
compliant	O
,	O
an	O
application	O
has	O
to	O
be	O
programmed	O
to	O
clean	O
up	O
its	O
own	O
data	O
from	O
the	O
local	O
machine	O
.	O
</s>
<s>
It	O
must	O
also	O
be	O
packaged	O
in	O
U3	B-Application
's	O
special	O
program	O
format	O
.	O
</s>
<s>
U3	B-Application
applications	O
will	O
only	O
run	O
from	O
a	O
U3	B-Application
device	O
.	O
</s>
<s>
U3	B-Application
programs	O
can	O
be	O
downloaded	O
from	O
the	O
U3	B-Application
website	O
and	O
other	O
places	O
.	O
</s>
<s>
Applications	O
include	O
Opera	B-Application
and	O
Skype	B-Application
and	O
do	O
not	O
need	O
to	O
be	O
installed	O
on	O
the	O
computer	B-General_Concept
.	O
</s>
<s>
The	O
U3	B-Application
application	B-Application
programming	I-Application
interfaces	I-Application
(	O
APIs	B-Application
)	O
allow	O
U3	B-Application
programs	O
lower-level	O
access	O
to	O
USB	O
flash	O
drive	O
,	O
and	O
to	O
query	O
the	O
drive	O
letter	O
.	O
</s>
<s>
The	O
U3	B-Application
APIs	B-Application
primarily	O
allow	O
developers	O
who	O
choose	O
to	O
use	O
more	O
of	O
the	O
power	O
of	O
U3	B-Application
to	O
control	O
how	O
their	O
application	O
handles	O
things	O
like	O
device	O
removal	O
and	O
saves	O
data	O
back	O
to	O
the	O
drive	O
such	O
as	O
configuration	O
or	O
documents	O
.	O
</s>
<s>
The	O
latest	O
version	O
of	O
U3	B-Application
launchpad	I-Application
supports	O
Windows	B-Application
2000	I-Application
with	O
Service	O
Pack	O
4	O
,	O
Windows	B-Application
XP	I-Application
,	O
Windows	B-Application
Vista	I-Application
,	O
Windows	B-Device
7	I-Device
and	O
Windows	B-Application
8	I-Application
.	O
</s>
<s>
Data	O
can	O
be	O
accessed	O
using	O
any	O
OS	O
capable	O
of	O
reading	O
from	O
USB	B-Architecture
mass	I-Architecture
storage	I-Architecture
devices	I-Architecture
,	O
unless	O
the	O
U3	B-Application
device	O
is	O
password-protected	O
.	O
</s>
<s>
Early	O
versions	O
of	O
the	O
U3	B-Application
launchpad	I-Application
software	O
had	O
Vista	B-Application
compatibility	O
issues	O
(	O
specifically	O
the	O
SanDisk	O
Cruzer	O
Titanium	O
series	O
with	O
device	O
numbers	O
2.17	O
,	O
2.18	O
,	O
2.19	O
and	O
2.20	O
)	O
,	O
although	O
this	O
problem	O
could	O
be	O
eliminated	O
by	O
updating	O
the	O
launcher	O
software	O
.	O
</s>
<s>
Prior	O
to	O
Sandisk	O
's	O
updated	O
launcher	O
software	O
being	O
released	O
,	O
Microsoft	O
supported	O
U3	B-Application
by	O
releasing	O
an	O
update	O
to	O
Vista	B-Application
.	O
</s>
<s>
Information	O
on	O
building	O
U3	B-Application
compliant	O
applications	O
and	O
the	O
U3	B-Application
software	I-Application
development	B-Application
kit	I-Application
were	O
available	O
to	O
registered	O
developers	O
at	O
the	O
official	O
U3	B-Application
website	O
.	O
</s>
<s>
Applications	O
that	O
do	O
not	O
require	O
installation	O
steps	O
in	O
order	O
to	O
run	O
can	O
easily	O
utilize	O
U3	B-Application
with	O
little	O
or	O
no	O
modification	O
by	O
taking	O
steps	O
to	O
either	O
not	O
modify	O
the	O
host	O
systems	O
files	B-Operating_System
or	O
registry	B-Protocol
,	O
or	O
undoing	O
all	O
changes	O
when	O
the	O
application	O
terminates	O
.	O
</s>
<s>
A	O
wizard	O
which	O
packages	O
distribution	O
files	B-Operating_System
and	O
creates	O
the	O
special	O
"	O
manifest	O
"	O
file	O
is	O
provided	O
.	O
</s>
<s>
As	O
of	O
May	O
2009	O
,	O
the	O
software	B-Application
development	I-Application
kit	I-Application
was	O
no	O
longer	O
available	O
;	O
the	O
u3.com	O
website	O
is	O
no	O
longer	O
available	O
.	O
</s>
<s>
The	O
virtual	O
CD-ROM	O
drive	O
cannot	O
be	O
removed	O
by	O
reformatting	O
because	O
it	O
is	O
presented	O
to	O
the	O
host	O
system	O
as	O
a	O
physical	O
device	O
attached	O
to	O
a	O
USB	O
hub	O
;	O
the	O
official	O
U3	B-Application
Launchpad	I-Application
Removal	O
Software	O
was	O
available	O
on	O
the	O
U3	B-Application
website	O
and	O
disabled	O
the	O
virtual	O
CD	O
drive	O
device	O
,	O
leaving	O
only	O
the	O
USB	B-Architecture
mass	I-Architecture
storage	I-Architecture
device	I-Architecture
active	O
on	O
the	O
U3	B-Application
USB	O
hub	O
controller	O
,	O
at	O
which	O
point	O
the	O
remaining	O
software	O
can	O
be	O
removed	O
by	O
a	O
subsequent	O
format	O
,	O
performed	O
by	O
the	O
removal	O
software	O
itself	O
.	O
</s>
<s>
Numerous	O
criticisms	O
have	O
been	O
made	O
of	O
the	O
U3	B-Application
platform	I-Application
.	O
</s>
<s>
Malware-like	O
integration	O
behaviour	O
Software	O
comes	O
preinstalled	O
on	O
USB	O
disk	O
and	O
,	O
when	O
using	O
stock	O
Windows	B-Application
settings	O
,	O
roots	O
itself	O
in	O
the	O
system	O
similar	O
to	O
malware	O
.	O
</s>
<s>
U3	B-Application
removal	O
is	O
possible	O
,	O
but	O
requires	O
complete	O
data	O
backup	O
.	O
</s>
<s>
Questioned	O
use	O
There	O
are	O
already	O
portable	O
versions	O
of	O
many	O
Windows	B-Application
software	O
available	O
,	O
some	B-Application
of	I-Application
which	I-Application
do	O
not	O
require	O
any	O
proprietary	B-Application
solution	O
to	O
work	O
.	O
</s>
<s>
Removed	O
user	O
data	O
,	O
but	O
not	O
all	O
of	O
it	O
Recent	O
files	B-Operating_System
and	O
programs	O
had	O
it	O
listed	O
.	O
</s>
<s>
Freezing	O
with	O
certain	O
CD	O
writing	O
software	O
There	O
is	O
a	O
possibility	O
of	O
slowing	O
down	O
or	O
freezing	O
Windows	B-Application
XP	I-Application
Pro	O
if	O
certain	O
Windows	B-Application
drivers	O
that	O
are	O
associated	O
with	O
high-volume	O
data	O
transfers	O
to	O
CD	O
writers	O
using	O
certain	O
CD/DVD	O
burning	O
software	O
installed	O
.	O
</s>
<s>
Proprietary	O
format/closed	O
platform	O
The	O
U3	B-Application
platform	I-Application
is	O
a	O
"	O
closed	O
"	O
platform	O
/	O
proprietary	B-Application
format	I-Application
.	O
</s>
<s>
SanDisk	O
,	O
the	O
rightsholders	O
for	O
U3	B-Application
,	O
ask	O
for	O
a	O
5%	O
royalty	O
from	O
USB	O
flash	O
drive	O
manufacturers	O
who	O
wish	O
to	O
implement	O
the	O
platform	O
on	O
their	O
products	O
.	O
</s>
<s>
Two	O
drive	O
letters	O
As	O
a	O
work-around	O
to	O
the	O
lack	O
of	O
Auto-Play	O
for	O
Flash	O
drives	O
on	O
older	O
versions	O
of	O
Windows	B-Application
,	O
the	O
U3	B-Application
software	I-Application
creates	O
two	O
drive	O
letters	O
(	O
one	O
which	O
presents	O
itself	O
as	O
a	O
CD	O
to	O
allow	O
Windows	B-Application
 '	O
auto-play	O
to	O
start	O
the	O
launcher	O
,	O
and	O
another	O
for	O
storing	O
user	O
data	O
)	O
.	O
</s>
<s>
Although	O
this	O
is	O
the	O
only	O
way	O
to	O
implement	O
auto-start	O
functionality	O
on	O
pre-Windows	O
XP	O
systems	O
,	O
it	O
could	O
be	O
considered	O
a	O
kludge	B-Architecture
,	O
and	O
the	O
extra	O
drive	O
letter	O
created	O
can	O
be	O
an	O
annoyance	O
.	O
</s>
<s>
However	O
,	O
it	O
is	O
possible	O
to	O
prevent	O
Windows	B-Application
from	O
allocating	O
a	O
drive	O
letter	O
for	O
the	O
"	O
CD	O
drive	O
"	O
via	O
the	O
Windows	B-Application
"	O
Disk	O
Management	O
"	O
tool	O
—	O
as	O
long	O
as	O
the	O
user	O
has	O
the	O
appropriate	O
rights/authority	O
to	O
do	O
so	O
.	O
</s>
<s>
Incompatibility	O
with	O
certain	O
embedded	B-Architecture
systems	I-Architecture
Some	O
host	O
systems	O
—	O
such	O
as	O
photo	O
kiosks	O
,	O
consumer	O
electronics	O
,	O
and	O
other	O
embedded	B-Architecture
computing	I-Architecture
devices	O
—	O
cannot	O
correctly	O
mount	O
U3	B-Application
"	O
smart	O
drives.	O
"	O
</s>
<s>
Although	O
some	O
newer	O
photo	O
kiosks	O
are	O
U3	B-Application
aware	O
and	O
can	O
overcome	O
this	O
limitation	O
,	O
it	O
still	O
exists	O
on	O
many	O
platforms	O
.	O
</s>
