<s>
Mount	B-Device
Rainier	I-Device
(	O
MRW	O
)	O
is	O
a	O
format	O
for	O
writable	O
optical	B-Device
discs	I-Device
which	O
provides	O
the	O
packet	B-Device
writing	I-Device
and	O
defect	O
management	O
.	O
</s>
<s>
Its	O
goal	O
is	O
the	O
replacement	O
of	O
the	O
floppy	B-Device
disk	I-Device
.	O
</s>
<s>
It	O
is	O
named	O
after	O
Mount	B-Device
Rainier	I-Device
,	O
a	O
volcano	O
near	O
Seattle	O
,	O
Washington	O
,	O
United	O
States	O
.	O
</s>
<s>
Mount	B-Device
Rainier	I-Device
can	O
be	O
used	O
only	O
with	O
drives	O
that	O
explicitly	O
support	O
it	O
(	O
a	O
part	O
of	O
SCSI/MMC	O
and	O
can	O
work	O
over	O
ATAPI	O
)	O
,	O
but	O
works	O
with	O
standard	O
CD-R	O
,	O
CD-RW	O
,	O
DVD+	O
/	O
-R	O
and	O
DVD+	O
/	O
-RW	O
media	O
.	O
</s>
<s>
The	O
physical	O
format	O
of	O
MRW	O
on	O
the	O
disk	O
is	O
managed	O
by	O
the	O
drive	O
's	O
firmware	B-Application
,	O
which	O
remaps	O
physical	O
drive	O
blocks	O
into	O
a	O
virtual	O
,	O
defect-free	O
space	O
.	O
</s>
<s>
Thus	O
,	O
the	O
host	O
computer	O
does	O
not	O
see	O
the	O
physical	O
format	O
of	O
the	O
disk	O
,	O
only	O
a	O
sequence	O
of	O
data	O
blocks	O
capable	O
of	O
holding	O
any	O
filesystem	B-Application
.	O
</s>
<s>
The	O
time	O
needed	O
for	O
the	O
disk	B-Application
formatting	I-Application
is	O
shortened	O
to	O
about	O
one	O
minute	O
by	O
the	O
background	O
formatting	O
capabilities	O
of	O
the	O
drive	O
.	O
</s>
<s>
Defective	O
sectors	O
are	O
recorded	O
at	O
a	O
table	O
in	O
the	O
lead-in	O
(	O
an	O
administrative	O
area	O
)	O
and	O
in	O
a	O
copy	O
of	O
the	O
table	O
in	O
the	O
lead-out	B-Application
.	O
</s>
<s>
From	O
the	O
host	O
computer	O
's	O
perspective	O
,	O
an	O
MRW	O
disc	O
provides	O
a	O
defect-free	O
block-accessible	O
device	O
,	O
upon	O
which	O
any	O
host	O
supported	O
filesystem	B-Application
may	O
be	O
written	O
.	O
</s>
<s>
Such	O
filesystems	B-Application
may	O
be	O
FAT32	B-Application
,	O
NTFS	B-Application
,	O
etc.	O
,	O
but	O
the	O
preferred	O
format	O
is	O
usually	O
UDF	O
1.02	O
,	O
as	O
this	O
file	O
format	O
is	O
widely	O
supported	O
.	O
</s>
<s>
An	O
MRW-formatted	O
CD-RW	O
with	O
a	O
UDF	O
filesystem	B-Application
gives	O
approximately	O
500	O
MB	O
free	O
space	O
.	O
</s>
<s>
It	O
is	O
even	O
possible	O
to	O
read	O
(	O
but	O
not	O
write	O
)	O
MRW	O
disks	O
without	O
an	O
MRW-compatible	O
drive	O
;	O
A	O
"	O
remapper	O
"	O
device	B-Application
driver	I-Application
is	O
needed	O
,	O
an	O
example	O
of	O
which	O
is	O
EasyWrite	B-Device
Reader	O
for	O
Windows	O
.	O
</s>
<s>
This	O
is	O
achieved	O
by	O
the	O
use	O
of	O
specialized	O
packet	B-Device
writing	I-Device
software	I-Device
,	O
or	O
operating	O
systems	O
that	O
support	O
UDF	O
versions	O
1.5	O
and	O
above	O
.	O
</s>
<s>
Mount	B-Device
Rainier	I-Device
is	O
implemented	O
natively	O
in	O
Windows	B-Application
Vista	I-Application
and	O
Windows	B-Device
7	I-Device
.	O
</s>
<s>
Linux	B-Operating_System
has	O
built-in	O
MRW	O
support	O
since	O
kernel	B-Operating_System
version	O
2.6.2	O
(	O
2004	O
)	O
.	O
</s>
<s>
Amiga	B-Application
OS4	I-Application
supports	O
this	O
natively	O
since	O
the	O
first	O
beta	O
appeared	O
in	O
2004	O
.	O
</s>
<s>
Support	O
for	O
reading	O
this	O
format	O
was	O
also	O
added	O
to	O
Mac	B-Operating_System
OS	I-Operating_System
X	I-Operating_System
.	O
</s>
<s>
Operating	O
systems	O
that	O
do	O
n't	O
support	O
MRW	O
natively	O
(	O
notably	O
Windows	B-Application
XP	I-Application
and	O
prior	O
versions	O
)	O
need	O
third-party	O
software	O
to	O
read	O
and	O
write	O
MRW-formatted	O
discs	O
,	O
and	O
these	O
tend	O
to	O
be	O
the	O
same	O
packet	B-Device
writing	I-Device
utilities	O
which	O
allow	O
native	O
UDF	O
filesystems	B-Application
to	O
be	O
written	O
to	O
optical	B-Device
media	I-Device
.	O
</s>
<s>
Some	O
optical	B-Device
disc	I-Device
software	O
,	O
such	O
as	O
IsoBuster	B-Application
,	O
can	O
support	O
Mount	B-Device
Rainier	I-Device
on	O
non-MR	O
drives	O
.	O
</s>
<s>
The	O
EasyWrite	B-Device
logo	O
is	O
the	O
marketing	O
symbol	O
created	O
by	O
Philips	O
for	O
CD	O
drives	O
that	O
are	O
Mount	B-Device
Rainier	I-Device
compatible	O
.	O
</s>
<s>
CD-MRW	B-Device
stands	O
for	O
Compact	O
disc	O
–	O
Mount	B-Device
Rainier	I-Device
Read/Write	O
.	O
</s>
