<s>
In	O
the	O
maintenance	O
of	O
file	B-Application
systems	I-Application
,	O
defragmentation	B-Application
is	O
a	O
process	O
that	O
reduces	O
the	O
degree	O
of	O
fragmentation	B-Application
.	O
</s>
<s>
It	O
does	O
this	O
by	O
physically	O
organizing	O
the	O
contents	O
of	O
the	O
mass	B-Device
storage	I-Device
device	I-Device
used	O
to	O
store	O
files	O
into	O
the	O
smallest	O
number	O
of	O
contiguous	B-Architecture
regions	O
(	O
fragments	O
,	O
extents	O
)	O
.	O
</s>
<s>
It	O
also	O
attempts	O
to	O
create	O
larger	O
regions	O
of	O
free	O
space	O
using	O
compaction	B-General_Concept
to	O
impede	O
the	O
return	O
of	O
fragmentation	B-Application
.	O
</s>
<s>
Some	O
defragmentation	B-Application
utilities	O
try	O
to	O
keep	O
smaller	O
files	O
within	O
a	O
single	O
directory	O
together	O
,	O
as	O
they	O
are	O
often	O
accessed	O
in	O
sequence	O
.	O
</s>
<s>
Defragmentation	B-Application
is	O
advantageous	O
and	O
relevant	O
to	O
file	B-Application
systems	I-Application
on	O
electromechanical	O
disk	B-Device
drives	I-Device
(	O
hard	B-Device
disk	I-Device
drives	I-Device
,	O
floppy	B-Device
disk	I-Device
drives	I-Device
and	O
optical	O
disk	B-Device
media	O
)	O
.	O
</s>
<s>
The	O
movement	O
of	O
the	O
hard	B-Device
drive	I-Device
's	O
read/write	B-Device
heads	I-Device
over	O
different	O
areas	O
of	O
the	O
disk	B-Device
when	O
accessing	O
fragmented	O
files	O
is	O
slower	O
,	O
compared	O
to	O
accessing	O
the	O
entire	O
contents	O
of	O
a	O
non-fragmented	O
file	B-Operating_System
sequentially	O
without	O
moving	O
the	O
read/write	B-Device
heads	I-Device
to	O
seek	O
other	O
fragments	O
.	O
</s>
<s>
Fragmentation	B-Application
occurs	O
when	O
the	O
file	B-Application
system	I-Application
cannot	O
or	O
will	O
not	O
allocate	O
enough	O
contiguous	B-Architecture
space	O
to	O
store	O
a	O
complete	O
file	B-Operating_System
as	O
a	O
unit	O
,	O
but	O
instead	O
puts	O
parts	O
of	O
it	O
in	O
gaps	O
between	O
existing	O
files	O
(	O
usually	O
those	O
gaps	O
exist	O
because	O
they	O
formerly	O
held	O
a	O
file	B-Operating_System
that	O
the	O
file	B-Application
system	I-Application
has	O
subsequently	O
deleted	O
or	O
because	O
the	O
file	B-Application
system	I-Application
allocated	O
excess	O
space	O
for	O
the	O
file	B-Operating_System
in	O
the	O
first	O
place	O
)	O
.	O
</s>
<s>
Files	O
that	O
are	O
often	O
appended	O
to	O
(	O
as	O
with	O
log	O
files	O
)	O
as	O
well	O
as	O
the	O
frequent	O
adding	O
and	O
deleting	O
of	O
files	O
(	O
as	O
with	O
emails	O
and	O
web	O
browser	O
cache	O
)	O
,	O
larger	O
files	O
(	O
as	O
with	O
videos	O
)	O
and	O
greater	O
numbers	O
of	O
files	O
contribute	O
to	O
fragmentation	B-Application
and	O
consequent	O
performance	O
loss	O
.	O
</s>
<s>
Defragmentation	B-Application
attempts	O
to	O
alleviate	O
these	O
problems	O
.	O
</s>
<s>
An	O
otherwise	O
blank	O
disk	B-Device
has	O
five	O
files	O
,	O
A	O
through	O
E	O
,	O
each	O
using	O
10	O
blocks	O
of	O
space	O
(	O
for	O
this	O
section	O
,	O
a	O
block	O
is	O
an	O
allocation	O
unit	O
of	O
the	O
filesystem	B-Application
;	O
the	O
block	B-Application
size	I-Application
is	O
set	O
when	O
the	O
disk	B-Device
is	O
formatted	O
and	O
can	O
be	O
any	O
size	O
supported	O
by	O
the	O
filesystem	B-Application
)	O
.	O
</s>
<s>
On	O
a	O
blank	O
disk	B-Device
,	O
all	O
of	O
these	O
files	O
would	O
be	O
allocated	O
one	O
after	O
the	O
other	O
(	O
see	O
example	O
1	O
in	O
the	O
image	O
)	O
.	O
</s>
<s>
If	O
file	B-Operating_System
B	O
were	O
to	O
be	O
deleted	O
,	O
there	O
would	O
be	O
two	O
options	O
:	O
mark	O
the	O
space	O
for	O
file	B-Operating_System
B	O
as	O
empty	O
to	O
be	O
used	O
again	O
later	O
,	O
or	O
move	O
all	O
the	O
files	O
after	O
B	O
so	O
that	O
the	O
empty	O
space	O
is	O
at	O
the	O
end	O
.	O
</s>
<s>
When	O
a	O
new	O
file	B-Operating_System
,	O
F	O
,	O
is	O
allocated	O
requiring	O
6	O
blocks	O
of	O
space	O
,	O
it	O
could	O
be	O
placed	O
into	O
the	O
first	O
6	O
blocks	O
of	O
the	O
space	O
that	O
formerly	O
held	O
file	B-Operating_System
B	O
,	O
and	O
the	O
4	O
blocks	O
following	O
it	O
will	O
remain	O
available	O
(	O
see	O
example	O
3	O
in	O
the	O
image	O
)	O
.	O
</s>
<s>
If	O
another	O
new	O
file	B-Operating_System
,	O
G	O
,	O
is	O
added	O
and	O
needs	O
only	O
4	O
blocks	O
,	O
it	O
could	O
then	O
occupy	O
the	O
space	O
after	O
F	O
and	O
before	O
C	O
(	O
example	O
4	O
in	O
the	O
image	O
)	O
.	O
</s>
<s>
However	O
,	O
if	O
file	B-Operating_System
F	O
then	O
needs	O
to	O
be	O
expanded	O
,	O
there	O
are	O
three	O
options	O
,	O
since	O
the	O
space	O
immediately	O
following	O
it	O
is	O
no	O
longer	O
available	O
:	O
</s>
<s>
Move	O
the	O
file	B-Operating_System
F	O
to	O
where	O
it	O
can	O
be	O
created	O
as	O
one	O
contiguous	B-Architecture
file	B-Operating_System
of	O
the	O
new	O
,	O
larger	O
size	O
.	O
</s>
<s>
This	O
would	O
not	O
be	O
possible	O
if	O
the	O
file	B-Operating_System
is	O
larger	O
than	O
the	O
largest	O
contiguous	B-Architecture
space	O
available	O
.	O
</s>
<s>
The	O
file	B-Operating_System
could	O
also	O
be	O
so	O
large	O
that	O
the	O
operation	O
would	O
take	O
an	O
undesirably	O
long	O
period	O
of	O
time	O
.	O
</s>
<s>
Move	O
all	O
the	O
files	O
after	O
F	O
until	O
one	O
opens	O
enough	O
space	O
to	O
make	O
it	O
contiguous	B-Architecture
again	O
.	O
</s>
<s>
Repeat	O
this	O
hundreds	O
of	O
times	O
and	O
the	O
filesystem	B-Application
will	O
have	O
a	O
number	O
of	O
small	O
free	O
segments	O
scattered	O
in	O
many	O
places	O
,	O
and	O
some	O
files	O
will	O
have	O
multiple	O
extents	O
.	O
</s>
<s>
When	O
a	O
file	B-Operating_System
has	O
many	O
extents	O
like	O
this	O
,	O
access	O
time	O
for	O
that	O
file	B-Operating_System
may	O
become	O
excessively	O
long	O
because	O
of	O
all	O
the	O
random	O
seeking	O
the	O
disk	B-Device
will	O
have	O
to	O
do	O
when	O
reading	O
it	O
.	O
</s>
<s>
Additionally	O
,	O
the	O
concept	O
of	O
“	O
fragmentation	B-Application
”	O
is	O
not	O
only	O
limited	O
to	O
individual	O
files	O
that	O
have	O
multiple	O
extents	O
on	O
the	O
disk	B-Device
.	O
</s>
<s>
For	O
instance	O
,	O
a	O
group	O
of	O
files	O
normally	O
read	O
in	O
a	O
particular	O
sequence	O
(	O
like	O
files	O
accessed	O
by	O
a	O
program	O
when	O
it	O
is	O
loading	O
,	O
which	O
can	O
include	O
certain	O
DLLs	O
,	O
various	O
resource	O
files	O
,	O
the	O
audio/visual	O
media	O
files	O
in	O
a	O
game	O
)	O
can	O
be	O
considered	O
fragmented	O
if	O
they	O
are	O
not	O
in	O
sequential	O
load-order	O
on	O
the	O
disk	B-Device
,	O
even	O
if	O
these	O
individual	O
files	O
are	O
not	O
fragmented	O
;	O
the	O
read/write	B-Device
heads	I-Device
will	O
have	O
to	O
seek	O
these	O
(	O
non-fragmented	O
)	O
files	O
randomly	O
to	O
access	O
them	O
in	O
sequence	O
.	O
</s>
<s>
Updates	O
are	O
a	O
common	O
cause	O
of	O
this	O
,	O
because	O
in	O
order	O
to	O
update	O
a	O
file	B-Operating_System
,	O
most	O
updaters	O
usually	O
delete	O
the	O
old	O
file	B-Operating_System
first	O
,	O
and	O
then	O
write	O
a	O
new	O
,	O
updated	O
one	O
in	O
its	O
place	O
.	O
</s>
<s>
However	O
,	O
most	O
filesystems	B-Application
do	O
not	O
write	O
the	O
new	O
file	B-Operating_System
in	O
the	O
same	O
physical	O
place	O
on	O
the	O
disk	B-Device
.	O
</s>
<s>
Defragmentation	B-Application
is	O
the	O
operation	O
of	O
moving	O
file	B-Operating_System
extents	O
(	O
physical	O
allocation	O
blocks	O
)	O
so	O
they	O
eventually	O
merge	O
,	O
preferably	O
into	O
one	O
.	O
</s>
<s>
Doing	O
so	O
usually	O
requires	O
at	O
least	O
two	O
copy	O
operations	O
:	O
one	O
to	O
move	O
the	O
blocks	O
into	O
some	O
free	O
scratch	O
space	O
on	O
the	O
disk	B-Device
so	O
more	O
movement	O
can	O
happen	O
,	O
and	O
another	O
to	O
finally	O
move	O
the	O
blocks	O
into	O
their	O
intended	O
place	O
.	O
</s>
<s>
In	O
such	O
a	O
paradigm	O
,	O
no	O
data	O
is	O
ever	O
removed	O
from	O
the	O
disk	B-Device
,	O
so	O
that	O
the	O
operation	O
can	O
be	O
safely	O
stopped	O
even	O
in	O
the	O
event	O
of	O
a	O
power	O
loss	O
.	O
</s>
<s>
To	O
defragment	B-Application
a	O
disk	B-Device
,	O
defragmentation	B-Application
software	I-Application
(	O
also	O
known	O
as	O
a	O
"	O
defragmenter	B-Application
"	O
)	O
can	O
only	O
move	O
files	O
around	O
within	O
the	O
free	O
space	O
available	O
.	O
</s>
<s>
This	O
is	O
an	O
intensive	O
operation	O
and	O
cannot	O
be	O
performed	O
on	O
a	O
filesystem	B-Application
with	O
little	O
or	O
no	O
free	O
space	O
.	O
</s>
<s>
During	O
defragmentation	B-Application
,	O
system	O
performance	O
will	O
be	O
degraded	O
,	O
and	O
it	O
is	O
best	O
to	O
leave	O
the	O
computer	O
alone	O
during	O
the	O
process	O
so	O
that	O
the	O
defragmenter	B-Application
does	O
not	O
get	O
confused	O
by	O
unexpected	O
changes	O
to	O
the	O
filesystem	B-Application
.	O
</s>
<s>
The	O
reorganization	O
involved	O
in	O
defragmentation	B-Application
does	O
not	O
change	O
logical	O
location	O
of	O
the	O
files	O
(	O
defined	O
as	O
their	O
location	O
within	O
the	O
directory	O
structure	O
)	O
.	O
</s>
<s>
Besides	O
defragmenting	B-Application
program	O
files	O
,	O
the	O
defragmenting	B-Application
tool	O
can	O
also	O
reduce	O
the	O
time	O
it	O
takes	O
to	O
load	O
programs	O
and	O
open	O
files	O
.	O
</s>
<s>
For	O
example	O
,	O
the	O
Windows	O
9x	O
defragmenter	B-Application
included	O
the	O
Intel	O
Application	O
Launch	O
Accelerator	O
which	O
optimized	O
programs	O
on	O
the	O
disk	B-Device
by	O
placing	O
the	O
defragmented	O
program	O
files	O
and	O
their	O
dependencies	O
next	O
to	O
each	O
other	O
,	O
in	O
the	O
order	O
in	O
which	O
the	O
program	O
loads	O
them	O
,	O
to	O
load	O
these	O
programs	O
faster	O
.	O
</s>
<s>
In	O
Windows	O
,	O
a	O
good	O
defragmenter	B-Application
will	O
read	O
the	O
Prefetch	O
files	O
to	O
identify	O
as	O
many	O
of	O
these	O
file	B-Operating_System
groups	O
as	O
possible	O
and	O
place	O
the	O
files	O
within	O
them	O
in	O
access	O
sequence	O
.	O
</s>
<s>
At	O
the	O
beginning	O
of	O
the	O
hard	B-Device
drive	I-Device
,	O
the	O
outer	O
tracks	O
have	O
a	O
higher	O
data	O
transfer	O
rate	O
than	O
the	O
inner	O
tracks	O
.	O
</s>
<s>
Third	O
party	O
defragmenters	B-Application
,	O
such	O
as	O
MyDefrag	O
,	O
will	O
move	O
frequently	O
accessed	O
files	O
onto	O
the	O
outer	O
tracks	O
and	O
defragment	B-Application
these	O
files	O
.	O
</s>
<s>
Improvements	O
in	O
modern	O
hard	B-Device
drives	I-Device
such	O
as	O
RAM	B-Architecture
cache	O
,	O
faster	O
platter	O
rotation	O
speed	O
,	O
command	O
queuing	O
(	O
SCSI/ATA	O
TCQ	O
or	O
SATA	O
NCQ	O
)	O
,	O
and	O
greater	O
data	O
density	O
reduce	O
the	O
negative	O
impact	O
of	O
fragmentation	B-Application
on	O
system	O
performance	O
to	O
some	O
degree	O
,	O
though	O
increases	O
in	O
commonly	O
used	O
data	O
quantities	O
offset	O
those	O
benefits	O
.	O
</s>
<s>
However	O
,	O
modern	O
systems	O
profit	O
enormously	O
from	O
the	O
huge	O
disk	B-Device
capacities	O
currently	O
available	O
,	O
since	O
partially	O
filled	O
disks	B-Device
fragment	O
much	O
less	O
than	O
full	O
disks	B-Device
,	O
and	O
on	O
a	O
high-capacity	O
HDD	O
,	O
the	O
same	O
partition	B-Application
occupies	O
a	O
smaller	O
range	O
of	O
cylinders	O
,	O
resulting	O
in	O
faster	O
seeks	O
.	O
</s>
<s>
Defragmentation	B-Application
is	O
just	O
that	O
:	O
ensuring	O
that	O
there	O
is	O
at	O
most	O
one	O
seek	O
per	O
file	B-Operating_System
,	O
counting	O
only	O
the	O
seeks	O
to	O
non-adjacent	O
tracks	O
.	O
</s>
<s>
A	O
common	O
strategy	O
to	O
optimize	O
defragmentation	B-Application
and	O
to	O
reduce	O
the	O
impact	O
of	O
fragmentation	B-Application
is	O
to	O
partition	B-Application
the	O
hard	O
disk(s )	O
in	O
a	O
way	O
that	O
separates	O
partitions	B-Application
of	O
the	O
file	B-Application
system	I-Application
that	O
experience	O
many	O
more	O
reads	O
than	O
writes	O
from	O
the	O
more	O
volatile	O
zones	O
where	O
files	O
are	O
created	O
and	O
deleted	O
frequently	O
.	O
</s>
<s>
If	O
files	O
from	O
user	O
profiles	O
are	O
held	O
on	O
a	O
dedicated	O
partition	B-Application
(	O
as	O
is	O
commonly	O
done	O
on	O
UNIX	B-Application
recommended	O
files	B-Application
systems	I-Application
,	O
where	O
it	O
is	O
typically	O
stored	O
in	O
the	O
/var	O
partition	B-Application
)	O
,	O
the	O
defragmenter	B-Application
runs	O
better	O
since	O
it	O
does	O
not	O
need	O
to	O
deal	O
with	O
all	O
the	O
static	O
files	O
from	O
other	O
directories	O
.	O
</s>
<s>
(	O
Alternatively	O
,	O
a	O
defragmenter	B-Application
can	O
be	O
told	O
to	O
simply	O
exclude	O
certain	O
file	B-Operating_System
paths	O
.	O
)	O
</s>
<s>
For	O
partitions	B-Application
with	O
relatively	O
little	O
write	O
activity	O
,	O
defragmentation	B-Application
time	O
greatly	O
improves	O
after	O
the	O
first	O
defragmentation	B-Application
,	O
since	O
the	O
defragmenter	B-Application
will	O
need	O
to	O
defragment	B-Application
only	O
a	O
small	O
number	O
of	O
new	O
files	O
in	O
the	O
future	O
.	O
</s>
<s>
The	O
presence	O
of	O
immovable	O
system	O
files	O
,	O
especially	O
a	O
swap	B-Architecture
file	I-Architecture
,	O
can	O
impede	O
defragmentation	B-Application
.	O
</s>
<s>
For	O
example	O
,	O
ntfsresize	B-Application
moves	O
these	O
files	O
to	O
resize	O
an	O
NTFS	B-Application
partition	B-Application
.	O
</s>
<s>
The	O
tool	O
PageDefrag	B-Application
could	O
defragment	B-Application
Windows	O
system	O
files	O
such	O
as	O
the	O
swap	B-Architecture
file	I-Architecture
and	O
the	O
files	O
that	O
store	O
the	O
Windows	B-Protocol
registry	I-Protocol
by	O
running	O
at	O
boot	O
time	O
before	O
the	O
GUI	O
is	O
loaded	O
.	O
</s>
<s>
Since	O
Windows	B-Application
Vista	I-Application
,	O
the	O
feature	O
is	O
not	O
fully	O
supported	O
and	O
has	O
not	O
been	O
updated	O
.	O
</s>
<s>
In	O
NTFS	B-Application
,	O
as	O
files	O
are	O
added	O
to	O
the	O
disk	B-Device
,	O
the	O
Master	O
File	B-Operating_System
Table	O
(	O
MFT	O
)	O
must	O
grow	O
to	O
store	O
the	O
information	O
for	O
the	O
new	O
files	O
.	O
</s>
<s>
Every	O
time	O
the	O
MFT	O
cannot	O
be	O
extended	O
due	O
to	O
some	O
file	B-Operating_System
being	O
in	O
the	O
way	O
,	O
the	O
MFT	O
will	O
gain	O
a	O
fragment	O
.	O
</s>
<s>
In	O
early	O
versions	O
of	O
Windows	O
,	O
it	O
could	O
not	O
be	O
safely	O
defragmented	O
while	O
the	O
partition	B-Application
was	O
mounted	O
,	O
and	O
so	O
Microsoft	O
wrote	O
a	O
hardblock	O
in	O
the	O
defragmenting	B-Application
API	B-Application
.	O
</s>
<s>
However	O
,	O
since	O
Windows	B-Application
XP	I-Application
,	O
an	O
increasing	O
number	O
of	O
defragmenters	B-Application
are	O
now	O
able	O
to	O
defragment	B-Application
the	O
MFT	O
,	O
because	O
the	O
Windows	O
defragmentation	B-Application
API	B-Application
has	O
been	O
improved	O
and	O
now	O
supports	O
that	O
move	O
operation	O
.	O
</s>
<s>
Even	O
with	O
the	O
improvements	O
,	O
the	O
first	O
four	O
clusters	O
of	O
the	O
MFT	O
remain	O
unmovable	O
by	O
the	O
Windows	O
defragmentation	B-Application
API	B-Application
,	O
resulting	O
in	O
the	O
fact	O
that	O
some	O
defragmenters	B-Application
will	O
store	O
the	O
MFT	O
in	O
two	O
fragments	O
:	O
The	O
first	O
four	O
clusters	O
wherever	O
they	O
were	O
placed	O
when	O
the	O
disk	B-Device
was	O
formatted	O
,	O
and	O
then	O
the	O
rest	O
of	O
the	O
MFT	O
at	O
the	O
beginning	O
of	O
the	O
disk	B-Device
(	O
or	O
wherever	O
the	O
defragmenter	B-Application
's	O
strategy	O
deems	O
to	O
be	O
the	O
best	O
place	O
)	O
.	O
</s>
<s>
When	O
reading	O
data	O
from	O
a	O
conventional	O
electromechanical	O
hard	B-Device
disk	I-Device
drive	I-Device
,	O
the	O
disk	B-Device
controller	O
must	O
first	O
position	O
the	O
head	O
,	O
relatively	O
slowly	O
,	O
to	O
the	O
track	O
where	O
a	O
given	O
fragment	O
resides	O
,	O
and	O
then	O
wait	O
while	O
the	O
disk	B-Device
platter	O
rotates	O
until	O
the	O
fragment	O
reaches	O
the	O
head	O
.	O
</s>
<s>
A	O
solid-state	B-Device
drive	I-Device
(	O
SSD	B-Device
)	O
is	O
based	O
on	O
flash	B-Device
memory	I-Device
with	O
no	O
moving	O
parts	O
,	O
so	O
random	B-General_Concept
access	I-General_Concept
of	O
a	O
file	B-Operating_System
fragment	O
on	O
flash	B-Device
memory	I-Device
does	O
not	O
suffer	O
this	O
delay	O
,	O
making	O
defragmentation	B-Application
to	O
optimize	O
access	O
speed	O
unnecessary	O
.	O
</s>
<s>
Furthermore	O
,	O
since	O
flash	B-Device
memory	I-Device
can	O
be	O
written	O
to	O
only	O
a	O
limited	O
number	O
of	O
times	O
before	O
it	O
fails	O
,	O
defragmentation	B-Application
is	O
actually	O
detrimental	O
(	O
except	O
in	O
the	O
mitigation	O
of	O
catastrophic	O
failure	O
)	O
.	O
</s>
<s>
However	O
,	O
Windows	O
still	O
defragments	B-Application
a	O
SSD	B-Device
automatically	O
(	O
albeit	O
less	O
vigorously	O
)	O
to	O
prevent	O
the	O
file	B-Application
system	I-Application
from	O
reaching	O
its	O
maximum	O
fragmentation	B-Application
tolerance	O
.	O
</s>
<s>
Once	O
the	O
maximum	O
fragmentation	B-Application
limit	O
is	O
reached	O
,	O
subsequent	O
attempts	O
to	O
write	O
to	O
disk	B-Device
fail	O
.	O
</s>
<s>
Although	O
many	O
SMR	B-Device
hard	B-Device
disks	I-Device
will	O
accept	O
TRIM	O
command	O
,	O
SMR	B-Device
hard	B-Device
disks	I-Device
still	O
need	O
defragmentation	B-Application
for	O
improved	O
performance	O
.	O
</s>
<s>
FAT	B-Application
:	O
MS-DOS	B-Application
6.x	I-Application
and	O
Windows	O
9x-systems	O
come	O
with	O
a	O
defragmentation	B-Application
utility	O
called	O
Defrag	B-Application
.	O
</s>
<s>
The	O
DOS	B-Device
version	O
is	O
a	O
limited	O
version	O
of	O
Norton	O
SpeedDisk	O
.	O
</s>
<s>
The	O
version	O
that	O
came	O
with	O
Windows	O
9x	O
was	O
licensed	O
from	O
Symantec	O
Corporation	O
,	O
and	O
the	O
version	O
that	O
came	O
with	O
Windows	B-Application
2000	I-Application
and	O
XP	B-Application
is	O
licensed	O
from	O
Condusiv	O
Technologies	O
.	O
</s>
<s>
NTFS	B-Application
was	O
introduced	O
with	O
Windows	B-Device
NT	I-Device
3.1	I-Device
,	O
but	O
the	O
NTFS	B-Application
filesystem	B-Application
driver	O
did	O
not	O
include	O
any	O
defragmentation	B-Application
capabilities	O
.	O
</s>
<s>
In	O
Windows	B-Device
NT	I-Device
4.0	I-Device
,	O
defragmenting	B-Application
APIs	B-Application
were	O
introduced	O
that	O
third-party	O
tools	O
could	O
use	O
to	O
perform	O
defragmentation	B-Application
tasks	O
;	O
however	O
,	O
no	O
defragmentation	B-Application
software	I-Application
was	O
included	O
.	O
</s>
<s>
In	O
Windows	B-Application
2000	I-Application
,	O
Windows	B-Application
XP	I-Application
and	O
Windows	B-Application
Server	I-Application
2003	I-Application
,	O
Microsoft	O
included	O
a	O
defragmentation	B-Application
tool	I-Application
based	O
on	O
Diskeeper	B-Application
that	O
made	O
use	O
of	O
the	O
defragmentation	B-Application
APIs	B-Application
and	O
was	O
a	O
snap-in	O
for	O
Computer	B-Application
Management	I-Application
.	O
</s>
<s>
In	O
Windows	B-Application
Vista	I-Application
,	O
Windows	B-Device
7	I-Device
and	O
Windows	B-Application
8	I-Application
,	O
the	O
tool	O
has	O
been	O
greatly	O
improved	O
and	O
was	O
given	O
a	O
new	O
interface	O
with	O
no	O
visual	O
diskmap	O
and	O
is	O
no	O
longer	O
part	O
of	O
Computer	B-Application
Management	I-Application
.	O
</s>
<s>
There	O
are	O
also	O
a	O
number	O
of	O
free	O
and	O
commercial	O
third-party	O
defragmentation	B-Application
products	O
available	O
for	O
Microsoft	B-Application
Windows	I-Application
.	O
</s>
<s>
BSD	B-Operating_System
UFS	B-Operating_System
and	O
particularly	O
FreeBSD	B-Operating_System
uses	O
an	O
internal	O
reallocator	O
that	O
seeks	O
to	O
reduce	O
fragmentation	B-Application
right	O
in	O
the	O
moment	O
when	O
the	O
information	O
is	O
written	O
to	O
disk	B-Device
.	O
</s>
<s>
Btrfs	B-Operating_System
has	O
online	O
and	O
automatic	O
defragmentation	B-Application
available	O
.	O
</s>
<s>
Linux	B-Application
ext2	B-Application
,	O
ext3	B-Application
,	O
and	O
ext4	B-Application
:	O
Much	O
like	O
UFS	B-Operating_System
,	O
these	O
filesystems	B-Application
employ	O
allocation	O
techniques	O
designed	O
to	O
keep	O
fragmentation	B-Application
under	O
control	O
at	O
all	O
times	O
.	O
</s>
<s>
As	O
a	O
result	O
,	O
defragmentation	B-Application
is	O
not	O
needed	O
in	O
the	O
vast	O
majority	O
of	O
cases	O
.	O
</s>
<s>
ext2	B-Application
uses	O
an	O
offline	O
defragmenter	B-Application
called	O
e2defrag	O
,	O
which	O
does	O
not	O
work	O
with	O
its	O
successor	O
ext3	B-Application
.	O
</s>
<s>
However	O
,	O
other	O
programs	O
,	O
or	O
filesystem-independent	O
ones	O
such	O
as	O
defragfs	O
,	O
may	O
be	O
used	O
to	O
defragment	B-Application
an	O
ext3	B-Application
filesystem	I-Application
.	O
</s>
<s>
ext4	B-Application
is	O
somewhat	O
backward	B-General_Concept
compatible	I-General_Concept
with	O
ext3	B-Application
,	O
and	O
thus	O
has	O
generally	O
the	O
same	O
amount	O
of	O
support	O
from	O
defragmentation	B-Application
programs	O
.	O
</s>
<s>
Currently	O
e4defrag	O
can	O
be	O
used	O
to	O
defragment	B-Application
an	O
ext4	B-Application
filesystem	I-Application
,	O
including	O
online	O
defragmentation	B-Application
.	O
</s>
<s>
VxFS	B-Application
has	O
the	O
fsadm	O
utility	O
that	O
includes	O
defrag	B-Application
operations	O
.	O
</s>
<s>
JFS	B-Application
has	O
the	O
defragfs	O
utility	O
on	O
IBM	O
operating	O
systems	O
.	O
</s>
<s>
HFS	B-Application
Plus	I-Application
introduced	O
in	O
1998	O
with	O
Mac	O
OS	O
8.1	O
has	O
a	O
number	O
of	O
optimizations	O
to	O
the	O
allocation	O
algorithms	O
in	O
an	O
attempt	O
to	O
defragment	B-Application
files	O
while	O
they	O
are	O
being	O
accessed	O
without	O
a	O
separate	O
defragmenter	B-Application
.	O
</s>
<s>
There	O
are	O
several	O
restrictions	O
for	O
files	O
to	O
be	O
candidates	O
for	O
'	O
on-the-fly	O
'	O
defragmentation	B-Application
(	O
including	O
a	O
maximum	O
size	O
20MB	O
)	O
.	O
</s>
<s>
On	O
traditional	O
Mac	O
OS	O
defragmentation	B-Application
can	O
be	O
done	O
by	O
Norton	O
SpeedDisk	O
and	O
TechTool	O
Pro	O
.	O
</s>
<s>
WAFL	B-Application
in	O
NetApp	O
's	O
ONTAP	O
7.2	O
operating	O
system	O
has	O
a	O
command	O
called	O
reallocate	O
that	O
is	O
designed	O
to	O
defragment	B-Application
large	O
files	O
.	O
</s>
<s>
XFS	B-Application
provides	O
an	O
online	O
defragmentation	B-Application
utility	O
called	O
xfs_fsr	O
.	O
</s>
<s>
SFS	B-Application
processes	O
the	O
defragmentation	B-Application
feature	O
in	O
almost	O
completely	O
stateless	O
way	O
(	O
apart	O
from	O
the	O
location	O
it	O
is	O
working	O
on	O
)	O
,	O
so	O
defragmentation	B-Application
can	O
be	O
stopped	O
and	O
started	O
instantly	O
.	O
</s>
<s>
ADFS	B-Device
,	O
the	O
file	B-Application
system	I-Application
used	O
by	O
RISC	B-Operating_System
OS	I-Operating_System
and	O
earlier	O
Acorn	O
Computers	O
,	O
keeps	O
file	B-Application
fragmentation	I-Application
under	O
control	O
without	O
requiring	O
manual	O
defragmentation	B-Application
.	O
</s>
