<s>
In	O
computer	B-General_Concept
science	I-General_Concept
,	O
a	O
double-sided	B-Architecture
disk	I-Architecture
is	O
a	O
disk	B-Device
of	O
which	O
both	O
sides	O
are	O
used	O
to	O
store	O
data	O
.	O
</s>
<s>
Early	O
floppy	B-Device
disks	I-Device
only	O
used	O
one	O
surface	O
for	O
recording	O
.	O
</s>
<s>
The	O
term	O
single-sided	B-Architecture
disk	I-Architecture
was	O
not	O
common	O
until	O
the	O
introduction	O
of	O
the	O
double-sided	B-Architecture
disk	I-Architecture
,	O
which	O
offered	O
double	O
the	O
capacity	O
in	O
the	O
same	O
physical	O
size	O
.	O
</s>
<s>
Initially	O
,	O
double-sided	B-Architecture
disks	I-Architecture
had	O
to	O
be	O
removed	O
and	O
flipped	O
over	O
to	O
access	O
data	O
on	O
the	O
other	O
side	O
,	O
but	O
eventually	O
devices	O
were	O
made	O
that	O
could	O
read	O
both	O
sides	O
without	O
the	O
need	O
to	O
eject	O
the	O
disk	B-Device
.	O
</s>
<s>
Manufacturers	O
sold	O
both	O
single-sided	O
and	O
double-sided	B-Architecture
disks	I-Architecture
with	O
the	O
double-sided	B-Architecture
disks	I-Architecture
being	O
typically	O
50%	O
more	O
expensive	O
than	O
single-sided	B-Architecture
disks	I-Architecture
.	O
</s>
<s>
While	O
the	O
magnetic-coated	O
medium	O
was	O
coated	O
on	O
both	O
sides	O
,	O
the	O
single-sided	O
floppies	B-Device
had	O
a	O
read-write	O
notch	O
on	O
only	O
one	O
side	O
,	O
thus	O
allowing	O
only	O
one	O
side	O
of	O
the	O
disk	B-Device
to	O
be	O
used	O
.	O
</s>
<s>
When	O
users	O
discovered	O
this	O
,	O
they	O
began	O
buying	O
the	O
less-expensive	O
single-sided	B-Architecture
disks	I-Architecture
and	O
"	O
notching	O
"	O
them	O
using	O
scissors	O
,	O
a	O
hole	O
punch	O
,	O
or	O
a	O
specially-designed	O
"	O
notcher	O
"	O
to	O
allow	O
them	O
to	O
write	O
to	O
the	O
reverse	O
side	O
of	O
the	O
disk	B-Device
.	O
</s>
<s>
It	O
is	O
more	O
convenient	O
(	O
and	O
cheaper	O
)	O
for	O
movies	O
to	O
be	O
released	O
on	O
single-sided	B-Architecture
discs	I-Architecture
,	O
with	O
the	O
film	O
and	O
extras	O
on	O
the	O
same	O
side	O
,	O
and	O
widescreen	O
and	O
letterbox	O
versions	O
packaged	O
separately	O
.	O
</s>
<s>
Indeed	O
,	O
a	O
few	O
DVD	O
titles	O
that	O
were	O
initially	O
issued	O
as	O
double-sided	B-Architecture
discs	I-Architecture
were	O
later	O
reissued	O
as	O
two	O
single-sided	B-Architecture
disc	I-Architecture
sets	O
.	O
</s>
