<s>
Double	B-Application
Tools	I-Application
for	I-Application
DoubleSpace	I-Application
is	O
a	O
software	B-Application
utility	I-Application
released	O
in	O
1993	O
by	O
the	O
Menlo	O
Park-based	O
company	O
Addstor	O
,	O
Inc	O
.	O
</s>
<s>
The	O
utility	O
functioned	O
as	O
an	O
add-on	O
to	O
the	O
disk	B-General_Concept
compression	I-General_Concept
software	O
DoubleSpace	B-General_Concept
,	O
supplied	O
with	O
MS-DOS	B-Application
6.0	I-Application
,	O
adding	O
a	O
number	O
of	O
features	O
not	O
available	O
in	O
the	O
standard	O
version	O
.	O
</s>
<s>
Most	O
of	O
the	O
Double	O
Tools	O
utilities	O
worked	O
from	O
Microsoft	B-Application
Windows	I-Application
,	O
providing	O
a	O
graphical	O
view	O
and	O
control	O
panel	O
of	O
the	O
compressed	O
drives	O
on	O
the	O
computer	O
(	O
the	O
utilities	O
supplied	O
with	O
MS-DOS	B-Application
only	O
operated	O
from	O
DOS-mode	O
)	O
.	O
</s>
<s>
One	O
of	O
the	O
unique	O
features	O
of	O
its	O
time	O
was	O
the	O
capability	O
to	O
defragment	O
a	O
DoubleSpace	B-General_Concept
compressed	O
drive	O
in	O
the	O
background	O
.	O
</s>
<s>
Some	O
of	O
the	O
features	O
,	O
including	O
the	O
background	O
defragmentation	O
capability	O
,	O
required	O
the	O
user	O
to	O
let	O
Double	O
Tools	O
replace	O
the	O
standard	O
compression	O
driver	O
for	O
MS-DOS	B-Application
(	O
DBLSPACE.BIN	O
)	O
with	O
one	O
developed	O
by	O
Addstor	O
,	O
claimed	O
to	O
be	O
100%	O
compatible	O
with	O
DoubleSpace	B-General_Concept
and	O
the	O
Microsoft	O
Real-Time	O
Compression	O
Interface	O
introduced	O
in	O
MS-DOS	B-Application
6.0	I-Application
.	O
</s>
<s>
This	O
driver	O
added	O
a	O
number	O
of	O
extra	O
features	O
,	O
such	O
as	O
the	O
use	O
of	O
32-bit	O
code	O
paths	O
when	O
it	O
detected	O
an	O
Intel	B-General_Concept
80386	I-General_Concept
or	O
higher	O
CPU	B-Device
,	O
caching	O
capabilities	O
and	O
-	O
in	O
addition	O
to	O
its	O
supporting	O
the	O
use	O
of	O
the	O
Upper	B-Device
Memory	I-Device
Area	I-Device
-	O
also	O
permitted	O
the	O
use	O
of	O
Extended	B-Device
Memory	I-Device
for	O
some	O
of	O
its	O
buffers	O
(	O
reducing	O
the	O
driver	O
's	O
total	O
footprint	O
in	O
conventional	B-Device
and	O
upper	B-Device
memory	I-Device
,	O
albeit	O
at	O
the	O
cost	O
of	O
somewhat	O
reduced	O
speed	O
)	O
.	O
</s>
<s>
Although	O
this	O
capability	O
was	O
later	O
introduced	O
into	O
the	O
standard	O
version	O
of	O
DoubleSpace	B-General_Concept
found	O
in	O
MS-DOS	B-Application
6.2	O
,	O
Double	O
Tools	O
also	O
had	O
the	O
capability	O
to	O
put	O
a	O
special	O
utility	O
on	O
compressed	O
floppy	B-Device
disks	I-Device
that	O
made	O
it	O
possible	O
to	O
access	O
the	O
compressed	O
data	O
even	O
on	O
computers	O
that	O
did	O
n't	O
have	O
DoubleSpace	B-General_Concept
(	O
or	O
Double	O
Tools	O
)	O
.	O
</s>
<s>
Another	O
interesting	O
function	O
was	O
the	O
ability	O
to	O
split	O
a	O
compressed	O
volume	O
over	O
multiple	O
floppy	B-Device
disks	I-Device
,	O
being	O
able	O
to	O
see	O
the	O
entire	O
volume	O
with	O
only	O
the	O
first	O
disk	O
inserted	O
(	O
and	O
being	O
prompted	O
to	O
change	O
discs	O
as	O
necessary	O
)	O
.	O
</s>
