<s>
Microsoft	B-Application
Drive	I-Application
Optimizer	I-Application
(	O
formerly	O
Disk	B-Application
Defragmenter	I-Application
)	O
is	O
a	O
utility	B-Application
in	O
Microsoft	B-Application
Windows	I-Application
designed	O
to	O
increase	O
data	O
access	O
speed	O
by	O
rearranging	O
files	B-Operating_System
stored	O
on	O
a	O
disk	B-Device
to	O
occupy	O
contiguous	B-Architecture
storage	O
locations	O
,	O
a	O
technique	O
called	O
defragmentation	B-Application
.	O
</s>
<s>
Defragmenting	B-Application
a	O
disk	B-Device
minimizes	O
head	O
travel	O
,	O
which	O
reduces	O
the	O
time	O
it	O
takes	O
to	O
read	O
files	B-Operating_System
from	O
and	O
write	O
files	B-Operating_System
to	O
the	O
disk	B-Device
.	O
</s>
<s>
As	O
a	O
result	O
of	O
the	O
decreased	O
read	O
and	O
write	O
times	O
,	O
Microsoft	B-Application
Drive	I-Application
Optimizer	I-Application
decreases	O
system	O
startup	O
times	O
for	O
systems	O
starting	O
from	O
magnetic	O
storage	O
devices	O
such	O
as	O
a	O
hard	B-Device
drive	I-Device
.	O
</s>
<s>
However	O
,	O
defragmentation	B-Application
is	O
not	O
helpful	O
on	O
storage	O
devices	O
such	O
as	O
solid	B-Device
state	I-Device
drives	I-Device
,	O
USB	O
drives	O
or	O
SD	B-Device
cards	I-Device
that	O
use	O
flash	B-Device
memory	I-Device
to	O
increase	O
speeds	O
,	O
as	O
these	O
drives	O
do	O
not	O
use	O
a	O
head	O
.	O
</s>
<s>
Defragmentation	B-Application
may	O
decrease	O
lifespan	O
for	O
certain	O
technologies	O
,	O
e.g.	O
</s>
<s>
solid	B-Device
state	I-Device
drives	I-Device
.	O
</s>
<s>
Microsoft	B-Application
Drive	I-Application
Optimizer	I-Application
was	O
first	O
officially	O
shipped	O
with	O
Windows	B-Application
XP	I-Application
.	O
</s>
<s>
From	O
Windows	O
8	O
,	O
the	O
program	O
was	O
renamed	O
to	O
Microsoft	B-Application
Drive	I-Application
Optimizer	I-Application
,	O
with	O
some	O
references	O
changed	O
to	O
say	O
Defragment	B-Application
and	O
Optimize	O
Drives	O
or	O
simply	O
Optimize	O
Drives	O
.	O
</s>
<s>
As	O
early	O
as	O
the	O
end	O
of	O
1982	O
,	O
the	O
IBM	B-Operating_System
PC	I-Operating_System
DOS	I-Operating_System
operating	O
system	O
that	O
shipped	O
with	O
early	O
IBM	B-Device
Personal	I-Device
Computers	I-Device
included	O
a	O
Disk	B-Device
Volume	O
Organization	O
Optimizer	O
to	O
defragment	B-Application
the	O
5¼-inch	O
floppy	B-Device
disks	I-Device
that	O
those	O
machines	O
used	O
.	O
</s>
<s>
At	O
this	O
time	O
,	O
Microsoft	O
's	O
MS-DOS	B-Application
did	O
not	O
defragment	B-Application
hard	B-Device
disks	I-Device
.	O
</s>
<s>
Several	O
third	O
party	O
software	O
developers	O
marketed	O
defragmenters	B-Application
to	O
fill	O
this	O
gap	O
.	O
</s>
<s>
MS-DOS	B-Application
6.0	O
introduced	O
Microsoft	O
Defrag	B-Application
.	O
</s>
<s>
Windows	B-Device
NT	I-Device
,	O
however	O
,	O
did	O
not	O
offer	O
a	O
Defrag	B-Application
utility	B-Application
,	O
and	O
Symantec	O
was	O
suggested	O
by	O
others	O
as	O
a	O
possible	O
alternative	O
for	O
the	O
utility	B-Application
.	O
</s>
<s>
Initial	O
releases	O
of	O
Windows	B-Device
NT	I-Device
lacked	O
a	O
defragmentation	B-Application
tool	O
.	O
</s>
<s>
Versions	O
through	O
Windows	B-Device
NT	I-Device
3.51	I-Device
did	O
not	O
have	O
an	O
application	B-Application
programming	I-Application
interface	I-Application
for	O
moving	O
data	B-Application
clusters	I-Application
on	O
hard	B-Device
disks	I-Device
.	O
</s>
<s>
Executive	O
Software	O
,	O
later	O
renamed	O
Diskeeper	B-Application
Corporation	O
,	O
released	O
Diskeeper	B-Application
defragmentation	B-Application
software	I-Application
for	O
Windows	B-Device
NT	I-Device
3.51	I-Device
,	O
which	O
shipped	O
with	O
a	O
customized	O
version	O
of	O
the	O
NT	O
kernel	O
and	O
file	O
system	O
drivers	O
that	O
could	O
move	O
clusters	O
.	O
</s>
<s>
Microsoft	O
included	O
file	O
system	O
control	O
(	O
FSCTL	O
)	O
commands	O
to	O
move	O
clusters	O
in	O
the	O
Windows	B-Device
NT	I-Device
4.0	I-Device
kernel	O
,	O
which	O
worked	O
for	O
both	O
NTFS	B-Application
and	O
FAT	B-Application
partitions	I-Application
.	O
</s>
<s>
However	O
,	O
Windows	B-Device
NT	I-Device
4.0	I-Device
did	O
not	O
provide	O
a	O
graphical	O
or	O
command-line	O
user	O
interface	O
.	O
</s>
<s>
Disk	B-Application
Defragmenter	I-Application
was	O
first	O
shipped	O
as	O
part	O
of	O
Windows	B-Application
95	I-Application
,	O
Windows	B-Device
98	I-Device
,	O
and	O
Windows	B-Device
Me	I-Device
,	O
and	O
was	O
licensed	O
from	O
Symantec	O
Corporation	O
.	O
</s>
<s>
In	O
the	O
version	O
included	O
with	O
Windows	B-Application
95	I-Application
and	O
98	O
,	O
if	O
the	O
contents	O
of	O
the	O
drive	O
changed	O
during	O
defragmentation	B-Application
,	O
the	O
program	O
paused	O
,	O
rescanned	O
the	O
entire	O
drive	O
,	O
and	O
then	O
resumed	O
the	O
process	O
from	O
where	O
it	O
had	O
left	O
off	O
.	O
</s>
<s>
In	O
Windows	B-Device
Me	I-Device
,	O
this	O
limitation	O
was	O
lifted	O
.	O
</s>
<s>
The	O
Disk	B-Application
Defragmenter	I-Application
in	O
Windows	B-Application
2000	I-Application
was	O
a	O
stripped-down	O
version	O
of	O
Diskeeper	B-Application
,	O
licensed	O
from	O
Diskeeper	B-Application
Corporation	O
.	O
</s>
<s>
Moving	O
infrequently	O
used	O
files	B-Operating_System
further	O
from	O
the	O
directory	O
area	O
.	O
</s>
<s>
Making	O
files	B-Operating_System
contiguous	B-Architecture
so	O
that	O
they	O
can	O
be	O
read	O
without	O
unnecessary	O
seeking	O
.	O
</s>
<s>
In	O
Windows	B-Application
2000	I-Application
and	O
later	O
operating	O
systems	O
,	O
Microsoft	B-Application
Drive	I-Application
Optimizer	I-Application
has	O
the	O
following	O
limitations	O
:	O
</s>
<s>
It	O
does	O
not	O
defragment	B-Application
files	B-Operating_System
residing	O
in	O
the	O
Recycle	O
Bin	O
or	O
files	B-Operating_System
that	O
are	O
in	O
use	O
.	O
</s>
<s>
Prior	O
to	O
the	O
Windows	B-Application
Vista	I-Application
release	O
,	O
only	O
one	O
volume	O
could	O
be	O
analyzed	O
or	O
defragmented	O
at	O
a	O
time	O
and	O
only	O
one	O
instance	O
could	O
run	O
.	O
</s>
<s>
The	O
GUI	O
version	O
prior	O
to	O
Windows	B-Application
Vista	I-Application
cannot	O
be	O
scheduled	O
.	O
</s>
<s>
However	O
,	O
the	O
command	O
line	O
utility	B-Application
since	O
Windows	B-Application
XP	I-Application
and	O
later	O
can	O
be	O
scheduled	O
.	O
</s>
<s>
Unlike	O
previous	O
versions	O
,	O
the	O
GUI	O
version	O
in	O
Windows	B-Application
Vista	I-Application
does	O
not	O
display	O
a	O
map	O
of	O
disk	B-Application
fragmentation	I-Application
,	O
nor	O
does	O
it	O
display	O
progress	O
during	O
defragmentation	B-Application
.	O
</s>
<s>
In	O
addition	O
,	O
the	O
Windows	B-Application
2000	I-Application
version	O
has	O
the	O
following	O
limitations	O
which	O
were	O
removed	O
in	O
Windows	B-Application
XP	I-Application
:	O
</s>
<s>
Defragmenting	B-Application
NTFS	B-Application
volumes	O
with	O
cluster	O
sizes	O
larger	O
than	O
4	O
kilobytes	O
(	O
KB	O
)	O
is	O
not	O
possible	O
.	O
</s>
<s>
It	O
is	O
not	O
possible	O
to	O
perform	O
fine-grained	O
movement	O
of	O
uncompressed	O
NTFS	B-Application
file	O
data	O
in	O
Windows	B-Application
2000	I-Application
.	O
</s>
<s>
EFS	O
encrypted	O
files	B-Operating_System
are	O
not	O
defragmented	O
.	O
</s>
<s>
Windows	B-Application
Disk	I-Application
Defragmenter	I-Application
was	O
updated	O
to	O
alleviate	O
some	O
restrictions	O
.	O
</s>
<s>
It	O
no	O
longer	O
relies	O
on	O
the	O
Windows	B-Device
NT	I-Device
Cache	O
Manager	O
,	O
which	O
prevented	O
the	O
defragmenter	B-Application
from	O
moving	O
pieces	O
of	O
a	O
file	O
that	O
cross	O
a	O
256KB	O
boundary	O
within	O
the	O
file	O
.	O
</s>
<s>
NTFS	B-Application
metadata	O
files	B-Operating_System
can	O
also	O
be	O
defragmented	O
.	O
</s>
<s>
A	O
command-line	O
tool	O
,	O
defrag.exe	B-Application
,	O
has	O
been	O
included	O
,	O
providing	O
access	O
to	O
the	O
defragmenter	B-Application
from	O
cmd.exe	B-Device
and	O
Task	O
Scheduler	O
.	O
</s>
<s>
In	O
Windows	B-Application
XP	I-Application
,	O
if	O
the	O
Master	O
File	O
Table	O
(	O
MFT	O
)	O
is	O
spread	O
into	O
multiple	O
fragments	O
,	O
defrag.exe	B-Application
and	O
the	O
GUI	O
version	O
can	O
combine	O
the	O
MFT	O
fragments	O
during	O
defragmentation	B-Application
.	O
</s>
<s>
Windows	B-Application
XP	I-Application
and	O
later	O
has	O
introduced	O
Boot	O
Files	B-Operating_System
Defragment	B-Application
function	O
,	O
this	O
function	O
is	O
enabled	O
by	O
default	O
and	O
can	O
be	O
disabled	O
in	O
Registry	O
.	O
</s>
<s>
In	O
Windows	B-Application
Vista	I-Application
,	O
Disk	B-Application
Defragmenter	I-Application
includes	O
an	O
option	O
to	O
automatically	O
run	O
at	O
scheduled	O
times	O
using	O
Task	O
Scheduler	O
and	O
uses	O
low	O
CPU	O
priority	O
and	O
the	O
newly	O
introduced	O
low	O
priority	O
I/O	O
algorithm	O
so	O
that	O
it	O
can	O
continue	O
to	O
defrag	B-Application
using	O
reduced	O
resources	O
(	O
less	O
CPU	O
and	O
disk	B-Device
read/write	O
activity	O
)	O
when	O
the	O
computer	O
is	O
in	O
use	O
.	O
</s>
<s>
The	O
user	O
interface	O
has	O
been	O
simplified	O
,	O
with	O
the	O
color	O
graph	O
,	O
progress	O
indicator	O
,	O
disk	B-Device
analysis	O
and	O
fragmentation	B-Application
information	O
being	O
removed	O
entirely	O
.	O
</s>
<s>
The	O
result	O
,	O
however	O
,	O
is	O
that	O
Disk	B-Application
Defragmenter	I-Application
does	O
not	O
require	O
a	O
certain	O
amount	O
of	O
free	O
space	O
in	O
order	O
to	O
successfully	O
defrag	B-Application
a	O
volume	O
,	O
unlike	O
performing	O
a	O
full	O
defragmentation	B-Application
which	O
requires	O
at	O
least	O
15%	O
of	O
free	O
space	O
on	O
the	O
volume	O
.	O
</s>
<s>
The	O
command	O
line	O
utility	B-Application
,	O
Defrag.exe	B-Application
,	O
offers	O
more	O
control	O
over	O
the	O
defragmentation	B-Application
process	O
,	O
such	O
as	O
performing	O
a	O
full	O
defragmentation	B-Application
by	O
consolidating	O
all	O
file	O
fragments	O
regardless	O
of	O
size	O
.	O
</s>
<s>
This	O
utility	B-Application
can	O
be	O
used	O
to	O
defragment	B-Application
specific	O
volumes	O
or	O
to	O
just	O
analyze	O
volumes	O
as	O
the	O
defragmenter	B-Application
would	O
in	O
Windows	B-Application
XP	I-Application
.	O
</s>
<s>
Disk	B-Application
Defragmenter	I-Application
is	O
maintained	O
by	O
Microsoft	O
's	O
Core	O
File	O
Services	O
.	O
</s>
<s>
The	O
Windows	B-Application
Vista	I-Application
version	I-Application
has	O
been	O
updated	O
in	O
Windows	B-Application
Vista	I-Application
SP1	O
to	O
include	O
the	O
improvements	O
made	O
in	O
Windows	B-Device
Server	I-Device
2008	I-Device
.	O
</s>
<s>
Notably	O
,	O
the	O
Windows	B-Application
Vista	I-Application
defragmenter	B-Application
is	O
much	O
more	O
effective	O
than	O
the	O
version	O
included	O
with	O
XP	B-Application
.	O
</s>
<s>
Windows	B-Device
7	I-Device
reintroduces	O
the	O
analyze	O
function	O
and	O
showing	O
percent	O
complete	O
of	O
the	O
defragmentation	B-Application
,	O
both	O
of	O
which	O
were	O
removed	O
in	O
Windows	B-Application
Vista	I-Application
.	O
</s>
<s>
It	O
can	O
also	O
defragment	B-Application
multiple	O
volumes	O
simultaneously	O
.	O
</s>
<s>
According	O
to	O
Scott	O
Hanselman	O
of	O
Microsoft	O
,	O
Windows	B-Device
7	I-Device
and	O
later	O
do	O
defragment	B-Application
a	O
solid-state	B-Device
disk	I-Device
(	O
SSD	B-Device
)	O
but	O
in	O
a	O
completely	O
different	O
way	O
.	O
</s>
<s>
There	O
is	O
less	O
incentive	O
for	O
defragmentation	B-Application
of	O
SSDs	B-Device
because	O
file	B-Application
fragmentation	I-Application
has	O
less	O
performance	O
impact	O
on	O
them	O
and	O
they	O
handle	O
a	O
finite	O
number	O
of	O
storage	O
cycles	O
before	O
their	O
lifespan	O
expires	O
.	O
</s>
<s>
However	O
,	O
file	O
systems	O
cannot	O
support	O
infinite	O
file	B-Application
fragmentation	I-Application
as	O
they	O
reach	O
their	O
metadata	O
limit	O
.	O
</s>
<s>
In	O
addition	O
,	O
Microsoft	B-Application
Drive	I-Application
Optimizer	I-Application
is	O
also	O
responsible	O
for	O
performing	O
the	O
TRIM	O
command	O
on	O
SSDs	B-Device
.	O
</s>
