<s>
PerfectDisk	B-Application
is	O
a	O
defragmentation	B-Application
software	I-Application
product	O
for	O
Windows	O
developed	O
by	O
Raxco	O
.	O
</s>
<s>
The	O
application	O
keeps	O
track	O
of	O
file	O
usage	O
to	O
lessen	O
defragmentation	B-Application
time	O
and	O
offers	O
two	O
modes	O
of	O
basic	O
defragging	B-Application
:	O
"	O
quick	O
"	O
and	O
"	O
SmartPlacement	O
"	O
.	O
</s>
<s>
PerfectDisk	B-Application
was	O
released	O
in	O
1990	O
for	O
the	O
VMS	B-Operating_System
operating	I-Operating_System
system	I-Operating_System
.	O
</s>
<s>
A	O
version	O
for	O
Windows	B-Device
NT	I-Device
followed	O
later	O
in	O
1997	O
.	O
</s>
<s>
PerfectDisk	B-Application
contains	O
scheduler	O
supporting	O
also	O
client	O
PCs	O
in	O
the	O
network	O
.	O
</s>
<s>
The	O
standard	O
Windows	O
"	O
Disk	B-Application
Defragmenter	I-Application
"	O
is	O
based	O
on	O
a	O
subset	O
of	O
a	O
competing	O
,	O
now-discontinued	O
product	O
named	O
Diskeeper	B-Application
.	O
</s>
<s>
For	O
those	O
seeking	O
additional	O
features	O
,	O
PerfectDisk	B-Application
and	O
the	O
full-feature	O
Diskeeper	B-Application
are	O
among	O
their	O
options	O
;	O
these	O
are	O
intended	O
for	O
high-end	O
users	O
,	O
and	O
feature	O
optimizing	O
the	O
placement	O
of	O
"	O
system	O
files	O
and	O
free	O
space.	O
"	O
</s>
