<s>
The	O
compressed	O
ROM/RAM	O
file	B-Application
system	I-Application
(	O
or	O
cramfs	B-Application
)	O
is	O
a	O
free	B-Application
(	O
GPL'ed	O
)	O
read-only	O
Linux	B-Operating_System
file	B-Application
system	I-Application
designed	O
for	O
simplicity	O
and	O
space-efficiency	O
.	O
</s>
<s>
It	O
is	O
mainly	O
used	O
in	O
embedded	B-Architecture
and	O
small-footprint	O
systems	O
.	O
</s>
<s>
Unlike	O
a	O
compressed	O
image	O
of	O
a	O
conventional	O
file	B-Application
system	I-Application
,	O
a	O
cramfs	B-Application
image	O
can	O
be	O
used	O
as	O
it	O
is	O
,	O
i.e.	O
</s>
<s>
For	O
this	O
reason	O
,	O
some	O
Linux	B-Application
distributions	I-Application
use	O
cramfs	B-Application
for	O
initrd	B-Application
images	O
(	O
Debian	O
3.1	O
in	O
particular	O
)	O
and	O
installation	O
images	O
(	O
SUSE	O
Linux	B-Operating_System
in	O
particular	O
)	O
,	O
where	O
there	O
are	O
constraints	O
on	O
memory	O
and	O
image	O
size	O
.	O
</s>
<s>
In	O
2013	O
,	O
Linux	B-Operating_System
maintainers	O
indicated	O
that	O
cramfs	B-Application
was	O
made	O
obsolete	O
by	O
squashfs	B-Application
,	O
but	O
the	O
file	B-Application
system	I-Application
got	O
rehabilitated	O
in	O
2017	O
for	O
use	O
in	O
low-memory	O
devices	O
where	O
using	O
squashfs	B-Application
may	O
not	O
be	O
viable	O
.	O
</s>
<s>
Files	O
on	O
cramfs	B-Application
file	B-Application
systems	I-Application
are	O
zlib-compressed	O
one	O
page	B-General_Concept
at	O
a	O
time	O
to	O
allow	O
random	O
read	O
access	O
.	O
</s>
<s>
The	O
metadata	O
is	O
not	O
compressed	O
,	O
but	O
is	O
expressed	O
in	O
a	O
terse	O
representation	O
that	O
is	O
more	O
space-efficient	O
than	O
conventional	O
file	B-Application
systems	I-Application
.	O
</s>
<s>
The	O
file	B-Application
system	I-Application
is	O
intentionally	O
read-only	O
to	O
simplify	O
its	O
design	O
;	O
random	O
write	O
access	O
for	O
compressed	O
files	O
is	O
difficult	O
to	O
implement	O
.	O
</s>
<s>
cramfs	B-Application
ships	O
with	O
a	O
utility	O
(	O
mkcramfs	B-Application
)	O
to	O
pack	O
files	O
into	O
new	O
cramfs	B-Application
images	O
.	O
</s>
<s>
Maximum	O
file	B-Application
system	I-Application
size	O
is	O
a	O
little	O
under	O
272MB	O
.	O
</s>
<s>
(	O
The	O
last	O
file	O
on	O
the	O
file	B-Application
system	I-Application
must	O
begin	O
before	O
the	O
256MB	O
block	O
,	O
but	O
can	O
extend	O
past	O
it	O
.	O
)	O
</s>
