<s>
Disk	B-Device
swapping	I-Device
refers	O
to	O
the	O
practice	O
of	O
inserting	O
and	O
removing	O
,	O
or	O
swapping	O
,	O
floppy	B-Device
disks	I-Device
in	O
a	O
floppy	O
disk	O
drive-based	O
computer	O
system	O
.	O
</s>
<s>
In	O
the	O
early	O
days	O
of	O
personal	B-Device
computers	I-Device
,	O
before	O
hard	B-Device
drives	I-Device
became	O
commonplace	O
,	O
most	O
fully	O
outfitted	O
computer	O
systems	O
had	O
two	O
floppy	B-Device
drives	I-Device
(	O
addressed	O
as	O
A	O
:	O
and	O
B	O
:	O
on	O
CP/M	B-Application
and	O
MS-DOSother	O
systems	O
had	O
different	O
conventions	O
)	O
.	O
</s>
<s>
Disk	B-Device
drives	I-Device
were	O
expensive	O
,	O
however	O
,	O
and	O
having	O
two	O
was	O
seen	O
as	O
a	O
luxury	O
by	O
many	O
computer	O
users	O
who	O
had	O
to	O
make	O
do	O
with	O
a	O
single	O
drive	O
.	O
</s>
<s>
The	O
purpose	O
of	O
two	O
floppy	B-Device
drives	I-Device
was	O
so	O
that	O
the	O
disk	B-Device
containing	O
the	O
application	B-Application
program	I-Application
could	O
remain	O
in	O
the	O
drive	O
while	O
the	O
data	O
disk	B-Device
containing	O
the	O
user	O
's	O
files	O
could	O
be	O
accessed	O
in	O
the	O
second	O
drive	O
.	O
</s>
<s>
In	O
order	O
to	O
use	O
a	O
function	O
of	O
the	O
program	O
not	O
loaded	O
into	O
memory	O
,	O
the	O
user	O
would	O
have	O
to	O
first	O
remove	O
the	O
data	O
disk	B-Device
,	O
then	O
insert	O
the	O
program	O
disk	B-Device
.	O
</s>
<s>
On	O
some	O
less-than-user-friendly	O
systems	O
,	O
this	O
could	O
result	O
in	O
data	B-General_Concept
loss	I-General_Concept
when	O
,	O
for	O
example	O
,	O
files	O
were	O
accidentally	O
saved	O
onto	O
the	O
program	O
disk	B-Device
.	O
</s>
<s>
Disk	B-Device
swapping	I-Device
was	O
an	O
infamous	O
feature	O
of	O
early	O
Macintosh	B-Device
128K	I-Device
systems	O
,	O
which	O
were	O
extremely	O
RAM-starved	O
.	O
</s>
