<s>
The	O
ext2	O
or	O
second	O
extended	B-Application
file	I-Application
system	I-Application
is	O
a	O
file	B-Application
system	I-Application
for	O
the	O
Linux	B-Operating_System
kernel	I-Operating_System
.	O
</s>
<s>
It	O
was	O
initially	O
designed	O
by	O
French	O
software	O
developer	O
Rémy	O
Card	O
as	O
a	O
replacement	O
for	O
the	O
extended	B-Application
file	I-Application
system	I-Application
(	O
ext	B-Application
)	O
.	O
</s>
<s>
Having	O
been	O
designed	O
according	O
to	O
the	O
same	O
principles	O
as	O
the	O
Berkeley	B-Operating_System
Fast	I-Operating_System
File	I-Operating_System
System	I-Operating_System
from	O
BSD	B-Operating_System
,	O
it	O
was	O
the	O
first	O
commercial-grade	O
filesystem	B-Application
for	O
Linux	B-Operating_System
.	O
</s>
<s>
The	O
canonical	O
implementation	O
of	O
ext2	O
is	O
the	O
"	O
ext2fs	O
"	O
filesystem	B-Application
driver	O
in	O
the	O
Linux	B-Operating_System
kernel	I-Operating_System
.	O
</s>
<s>
Other	O
implementations	O
(	O
of	O
varying	O
quality	O
and	O
completeness	O
)	O
exist	O
in	O
GNU	B-Application
Hurd	I-Application
,	O
MINIX	B-Application
3	I-Application
,	O
some	O
BSD	B-Operating_System
kernels	B-Operating_System
,	O
in	O
MiNT	B-Application
,	O
Haiku	B-Language
and	O
as	O
third-party	O
Microsoft	B-Application
Windows	I-Application
and	O
macOS	B-Application
drivers	O
.	O
</s>
<s>
ext2	O
was	O
the	O
default	O
filesystem	B-Application
in	O
several	O
Linux	B-Application
distributions	I-Application
,	O
including	O
Debian	O
and	O
Red	O
Hat	O
Linux	B-Operating_System
,	O
until	O
supplanted	O
by	O
ext3	B-Application
,	O
which	O
is	O
almost	O
completely	O
compatible	O
with	O
ext2	O
and	O
is	O
a	O
journaling	B-Application
file	I-Application
system	I-Application
.	O
</s>
<s>
ext2	O
is	O
still	O
the	O
filesystem	B-Application
of	O
choice	O
for	O
flash-based	O
storage	O
media	O
(	O
such	O
as	O
SD	B-Device
cards	I-Device
and	O
USB	O
flash	B-Device
drives	O
)	O
because	O
its	O
lack	O
of	O
a	O
journal	O
increases	O
performance	O
and	O
minimizes	O
the	O
number	O
of	O
writes	O
,	O
and	O
flash	B-Device
devices	O
can	O
endure	O
a	O
limited	O
number	O
of	O
write	O
cycles	O
.	O
</s>
<s>
Since	O
2009	O
,	O
the	O
Linux	B-Operating_System
kernel	I-Operating_System
supports	O
a	O
journal-less	O
mode	O
of	O
ext4	B-Application
which	O
provides	O
benefits	O
not	O
found	O
with	O
ext2	O
,	O
such	O
as	O
larger	O
file	O
and	O
volume	O
sizes	O
.	O
</s>
<s>
The	O
early	O
development	O
of	O
the	O
Linux	B-Operating_System
kernel	I-Operating_System
was	O
made	O
as	O
a	O
cross-development	O
under	O
the	O
MINIX	B-Operating_System
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
The	O
MINIX	B-Application
file	I-Application
system	I-Application
was	O
used	O
as	O
Linux	B-Operating_System
's	O
first	O
file	B-Application
system	I-Application
.	O
</s>
<s>
The	O
Minix	B-Application
file	I-Application
system	I-Application
was	O
mostly	O
free	O
of	O
bugs	B-Error_Name
,	O
but	O
used	O
16-bit	O
offsets	O
internally	O
and	O
thus	O
had	O
a	O
maximum	O
size	O
limit	O
of	O
only	O
64	O
megabytes	O
,	O
and	O
there	O
was	O
also	O
a	O
filename	O
length	O
limit	O
of	O
14	O
characters	O
.	O
</s>
<s>
Because	O
of	O
these	O
limitations	O
,	O
work	O
began	O
on	O
a	O
replacement	O
native	O
file	B-Application
system	I-Application
for	O
Linux	B-Operating_System
.	O
</s>
<s>
To	O
ease	O
the	O
addition	O
of	O
new	O
file	B-Application
systems	I-Application
and	O
provide	O
a	O
generic	O
file	O
API	B-Application
,	O
VFS	B-Application
,	O
a	O
virtual	B-Application
file	I-Application
system	I-Application
layer	O
,	O
was	O
added	O
to	O
the	O
Linux	B-Operating_System
kernel	I-Operating_System
.	O
</s>
<s>
The	O
extended	B-Application
file	I-Application
system	I-Application
(	O
ext	B-Application
)	O
,	O
was	O
released	O
in	O
April	O
1992	O
as	O
the	O
first	O
file	B-Application
system	I-Application
using	O
the	O
VFS	B-Application
API	B-Application
and	O
was	O
included	O
in	O
Linux	B-Operating_System
version	O
0.96c	O
.	O
</s>
<s>
The	O
ext	B-Application
file	B-Application
system	I-Application
solved	O
the	O
two	O
major	O
problems	O
in	O
the	O
Minix	B-Application
file	I-Application
system	I-Application
(	O
maximum	O
partition	O
size	O
and	O
filename	O
length	O
limitation	O
to	O
14	O
characters	O
)	O
,	O
and	O
allowed	O
2	O
gigabytes	O
of	O
data	O
and	O
filenames	O
of	O
up	O
to	O
255	O
characters	O
.	O
</s>
<s>
But	O
it	O
still	O
had	O
problems	O
:	O
there	O
was	O
no	O
support	O
of	O
separate	O
timestamps	O
for	O
file	B-Application
access	I-Application
,	O
inode	B-Application
modification	O
,	O
and	O
data	O
modification	O
.	O
</s>
<s>
As	O
a	O
solution	O
for	O
these	O
problems	O
,	O
two	O
new	O
filesystems	B-Application
were	O
developed	O
in	O
January	O
1993	O
for	O
Linux	B-Operating_System
kernel	I-Operating_System
0.99	O
:	O
xiafs	B-Application
and	O
the	O
second	O
extended	B-Application
file	I-Application
system	I-Application
(	O
ext2	O
)	O
,	O
which	O
was	O
an	O
overhaul	O
of	O
the	O
extended	B-Application
file	I-Application
system	I-Application
incorporating	O
many	O
ideas	O
from	O
the	O
Berkeley	B-Operating_System
Fast	I-Operating_System
File	I-Operating_System
System	I-Operating_System
.	O
</s>
<s>
Since	O
then	O
,	O
ext2	O
has	O
been	O
a	O
testbed	O
for	O
many	O
of	O
the	O
new	O
extensions	O
to	O
the	O
VFS	B-Application
API	B-Application
.	O
</s>
<s>
Features	O
such	O
as	O
the	O
withdrawn	O
POSIX	O
draft	O
ACL	O
proposal	O
and	O
the	O
withdrawn	O
extended	B-Application
attribute	I-Application
proposal	O
were	O
generally	O
implemented	O
first	O
on	O
ext2	O
because	O
it	O
was	O
relatively	O
simple	O
to	O
extend	O
and	O
its	O
internals	O
were	O
well	O
understood	O
.	O
</s>
<s>
On	O
Linux	B-Operating_System
kernels	I-Operating_System
prior	O
to	O
2.6.17	O
,	O
restrictions	O
in	O
the	O
block	B-General_Concept
driver	O
mean	O
that	O
ext2	O
filesystems	B-Application
have	O
a	O
maximum	O
file	O
size	O
of	O
2TiB	O
.	O
</s>
<s>
ext2	O
is	O
still	O
recommended	O
over	O
journaling	B-Application
file	I-Application
systems	I-Application
on	O
bootable	O
USB	O
flash	B-Device
drives	O
and	O
other	O
solid-state	B-Device
drives	I-Device
.	O
</s>
<s>
ext2	O
performs	O
fewer	O
writes	O
than	O
ext3	B-Application
because	O
there	O
is	O
no	O
journaling	O
.	O
</s>
<s>
As	O
the	O
major	O
aging	O
factor	O
of	O
a	O
flash	B-Device
chip	I-Device
is	O
the	O
number	O
of	O
erase	O
cycles	O
,	O
and	O
as	O
erase	O
cycles	O
happen	O
frequently	O
on	O
writes	O
,	O
decreasing	O
writes	O
increases	O
the	O
life	O
span	O
of	O
the	O
solid-state	O
device	O
.	O
</s>
<s>
Another	O
good	O
practice	O
for	O
filesystems	B-Application
on	O
flash	B-Device
devices	O
is	O
the	O
use	O
of	O
the	O
noatime	O
mount	O
option	O
,	O
for	O
the	O
same	O
reason	O
.	O
</s>
<s>
The	O
space	O
in	O
ext2	O
is	O
split	O
up	O
into	O
blocks	B-General_Concept
.	O
</s>
<s>
These	O
blocks	B-General_Concept
are	O
grouped	O
into	O
block	B-General_Concept
groups	O
,	O
analogous	O
to	O
cylinder	O
groups	O
in	O
the	O
Unix	B-Operating_System
File	I-Operating_System
System	I-Operating_System
.	O
</s>
<s>
There	O
are	O
typically	O
thousands	O
of	O
blocks	B-General_Concept
on	O
a	O
large	O
file	B-Application
system	I-Application
.	O
</s>
<s>
Data	O
for	O
any	O
given	O
file	O
is	O
typically	O
contained	O
within	O
a	O
single	O
block	B-General_Concept
group	O
where	O
possible	O
.	O
</s>
<s>
Each	O
block	B-General_Concept
group	O
contains	O
a	O
copy	O
of	O
the	O
superblock	O
and	O
block	B-General_Concept
group	O
descriptor	O
table	O
,	O
and	O
all	O
block	B-General_Concept
groups	O
contain	O
a	O
block	B-General_Concept
bitmap	O
,	O
an	O
inode	B-Application
bitmap	O
,	O
an	O
inode	B-Application
table	O
,	O
and	O
finally	O
the	O
actual	O
data	O
blocks	B-General_Concept
.	O
</s>
<s>
The	O
superblock	O
contains	O
important	O
information	O
that	O
is	O
crucial	O
to	O
the	O
booting	O
of	O
the	O
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
Thus	O
backup	O
copies	O
are	O
made	O
in	O
multiple	O
block	B-General_Concept
groups	O
in	O
the	O
file	B-Application
system	I-Application
.	O
</s>
<s>
However	O
,	O
typically	O
only	O
the	O
first	O
copy	O
of	O
it	O
,	O
which	O
is	O
found	O
at	O
the	O
first	O
block	B-General_Concept
of	O
the	O
file	B-Application
system	I-Application
,	O
is	O
used	O
in	O
the	O
booting	O
.	O
</s>
<s>
The	O
group	O
descriptor	O
stores	O
the	O
location	O
of	O
the	O
block	B-General_Concept
bitmap	O
,	O
inode	B-Application
bitmap	O
,	O
and	O
the	O
start	O
of	O
the	O
inode	B-Application
table	O
for	O
every	O
block	B-General_Concept
group	O
.	O
</s>
<s>
Every	O
file	O
or	O
directory	B-Application
is	O
represented	O
by	O
an	O
inode	B-Application
.	O
</s>
<s>
The	O
term	O
"	O
inode	B-Application
"	O
comes	O
from	O
"	O
index	B-Application
node	I-Application
"	O
(	O
over	O
time	O
,	O
it	O
became	O
i-node	B-Application
and	O
then	O
inode	B-Application
)	O
.	O
</s>
<s>
The	O
inode	B-Application
includes	O
data	O
about	O
the	O
size	O
,	O
permission	O
,	O
ownership	O
,	O
and	O
location	O
on	O
disk	O
of	O
the	O
file	O
or	O
directory	B-Application
.	O
</s>
<s>
Example	O
of	O
ext2	O
inode	B-Application
structure	O
:	O
</s>
<s>
Quote	O
from	O
the	O
Linux	B-Operating_System
kernel	I-Operating_System
documentation	O
for	O
ext2	O
:	O
</s>
<s>
"	O
There	O
are	O
pointers	O
to	O
the	O
first	O
12	O
blocks	B-General_Concept
which	O
contain	O
the	O
file	O
's	O
data	O
in	O
the	O
inode	B-Application
.	O
</s>
<s>
There	O
is	O
a	O
pointer	O
to	O
an	O
indirect	O
block	B-General_Concept
(	O
which	O
contains	O
pointers	O
to	O
the	O
next	O
set	O
of	O
blocks	B-General_Concept
)	O
,	O
a	O
pointer	O
to	O
a	O
doubly	O
indirect	O
block	B-General_Concept
and	O
a	O
pointer	O
to	O
a	O
trebly	O
indirect	O
block.	O
"	O
</s>
<s>
Pointers	O
1	O
to	O
12	O
point	O
to	O
direct	O
blocks	B-General_Concept
,	O
pointer	O
13	O
points	O
to	O
an	O
indirect	O
block	B-General_Concept
,	O
pointer	O
14	O
points	O
to	O
a	O
doubly	O
indirect	O
block	B-General_Concept
,	O
and	O
pointer	O
15	O
points	O
to	O
a	O
triply	O
indirect	O
block	B-General_Concept
.	O
</s>
<s>
Each	O
directory	B-Application
is	O
a	O
list	O
of	O
directory	B-Application
entries	O
.	O
</s>
<s>
Each	O
directory	B-Application
entry	O
associates	O
one	O
file	O
name	O
with	O
one	O
inode	B-Application
number	I-Application
,	O
and	O
consists	O
of	O
the	O
inode	B-Application
number	I-Application
,	O
the	O
length	O
of	O
the	O
file	O
name	O
,	O
and	O
the	O
actual	O
text	O
of	O
the	O
file	O
name	O
.	O
</s>
<s>
To	O
find	O
a	O
file	O
,	O
the	O
directory	B-Application
is	O
searched	O
front-to-back	O
for	O
the	O
associated	O
filename	O
.	O
</s>
<s>
For	O
reasonable	O
directory	B-Application
sizes	O
,	O
this	O
is	O
fine	O
.	O
</s>
<s>
But	O
for	O
very	O
large	O
directories	B-Application
this	O
is	O
inefficient	O
,	O
and	O
ext3	B-Application
offers	O
a	O
second	O
way	O
of	O
storing	O
directories	B-Application
(	O
HTree	B-Library
)	O
that	O
is	O
more	O
efficient	O
than	O
just	O
a	O
list	O
of	O
filenames	O
.	O
</s>
<s>
The	O
root	O
directory	B-Application
is	O
always	O
stored	O
in	O
inode	B-Application
number	I-Application
two	O
,	O
so	O
that	O
the	O
file	B-Application
system	I-Application
code	O
can	O
find	O
it	O
at	O
mount	O
time	O
.	O
</s>
<s>
Subdirectories	B-Application
are	O
implemented	O
by	O
storing	O
the	O
name	O
of	O
the	O
subdirectory	B-Application
in	O
the	O
name	O
field	O
,	O
and	O
the	O
inode	B-Application
number	I-Application
of	O
the	O
subdirectory	B-Application
in	O
the	O
inode	B-Application
field	O
.	O
</s>
<s>
Hard	O
links	O
are	O
implemented	O
by	O
storing	O
the	O
same	O
inode	B-Application
number	I-Application
with	O
more	O
than	O
one	O
file	O
name	O
.	O
</s>
<s>
Accessing	O
the	O
file	O
by	O
either	O
name	O
results	O
in	O
the	O
same	O
inode	B-Application
number	I-Application
,	O
and	O
therefore	O
the	O
same	O
data	O
.	O
</s>
<s>
The	O
special	O
directories	B-Application
"	O
.	O
"	O
</s>
<s>
(	O
current	O
directory	B-Application
)	O
and	O
"	O
..	B-Application
"	O
(	O
parent	B-Application
directory	I-Application
)	O
are	O
implemented	O
by	O
storing	O
the	O
names	O
"	O
.	O
"	O
</s>
<s>
and	O
"	O
..	B-Application
"	O
in	O
the	O
directory	B-Application
,	O
and	O
the	O
inode	B-Application
number	I-Application
of	O
the	O
current	O
and	O
parent	B-Application
directories	I-Application
in	O
the	O
inode	B-Application
field	O
.	O
</s>
<s>
The	O
only	O
special	O
treatment	O
these	O
two	O
entries	O
receive	O
is	O
that	O
they	O
are	O
automatically	O
created	O
when	O
any	O
new	O
directory	B-Application
is	O
made	O
,	O
and	O
they	O
cannot	O
be	O
deleted	O
.	O
</s>
<s>
When	O
a	O
new	O
file	O
or	O
directory	B-Application
is	O
created	O
,	O
ext2	O
must	O
decide	O
where	O
to	O
store	O
the	O
data	O
.	O
</s>
<s>
ext2	O
attempts	O
to	O
allocate	O
each	O
new	O
directory	B-Application
in	O
the	O
group	O
containing	O
its	O
parent	B-Application
directory	I-Application
,	O
on	O
the	O
theory	O
that	O
accesses	O
to	O
parent	O
and	O
children	O
directories	B-Application
are	O
likely	O
to	O
be	O
closely	O
related	O
.	O
</s>
<s>
ext2	O
also	O
attempts	O
to	O
place	O
files	B-Operating_System
in	O
the	O
same	O
group	O
as	O
their	O
directory	B-Application
entries	O
,	O
because	O
directory	B-Application
accesses	O
often	O
lead	O
to	O
file	O
accesses	O
.	O
</s>
<s>
However	O
,	O
if	O
the	O
group	O
is	O
full	O
,	O
then	O
the	O
new	O
file	O
or	O
new	O
directory	B-Application
is	O
placed	O
in	O
some	O
other	O
non-full	O
group	O
.	O
</s>
<s>
The	O
data	O
blocks	B-General_Concept
needed	O
to	O
store	O
directories	B-Application
and	O
files	B-Operating_System
can	O
be	O
found	O
by	O
looking	O
in	O
the	O
data	O
allocation	O
bitmap	O
.	O
</s>
<s>
Any	O
needed	O
space	O
in	O
the	O
inode	B-Application
table	O
can	O
be	O
found	O
by	O
looking	O
in	O
the	O
inode	B-Application
allocation	O
bitmap	O
.	O
</s>
<s>
+	O
Theoretical	O
ext2	O
limits	O
under	O
Linux	B-Operating_System
Block	B-General_Concept
size	I-General_Concept
:	O
1	O
KiB	O
2	O
KiB	O
4	O
KiB	O
8	O
KiB	O
max	O
.	O
</s>
<s>
The	O
reason	O
for	O
some	O
limits	O
of	O
ext2	O
are	O
the	O
file	O
format	O
of	O
the	O
data	O
and	O
the	O
operating	B-General_Concept
system	I-General_Concept
's	O
kernel	B-Operating_System
.	O
</s>
<s>
Mostly	O
these	O
factors	O
will	O
be	O
determined	O
once	O
when	O
the	O
file	B-Application
system	I-Application
is	O
built	O
.	O
</s>
<s>
They	O
depend	O
on	O
the	O
block	B-General_Concept
size	I-General_Concept
and	O
the	O
ratio	O
of	O
the	O
number	O
of	O
blocks	B-General_Concept
and	O
inodes	B-Application
.	O
</s>
<s>
In	O
Linux	B-Operating_System
the	O
block	B-General_Concept
size	I-General_Concept
is	O
limited	O
by	O
the	O
architecture	O
page	B-General_Concept
size	I-General_Concept
.	O
</s>
<s>
There	O
are	O
also	O
some	O
userspace	O
programs	O
that	O
cannot	O
handle	O
files	B-Operating_System
larger	O
than	O
2	O
GiB	O
.	O
</s>
<s>
If	O
b	O
is	O
the	O
block	B-General_Concept
size	I-General_Concept
,	O
the	O
maximal	O
file	O
size	O
is	O
limited	O
to	O
min( 	O
( ( 	O
b/4	O
)	O
3	O
+	O
(	O
b/4	O
)	O
2	O
+	O
b/4	O
+	O
12	O
)	O
×	O
b	O
,	O
(	O
232	O
−	O
1	O
)	O
×	O
512	O
)	O
due	O
to	O
the	O
i_block	O
structure	O
(	O
an	O
array	O
of	O
direct/indirect	O
EXT2_N_BLOCKS	O
)	O
and	O
i_blocks	O
(	O
32-bit	O
integer	O
value	O
)	O
representing	O
the	O
number	O
of	O
512-byte	O
"	O
blocks	B-General_Concept
"	O
in	O
the	O
file	O
.	O
</s>
<s>
The	O
maximal	O
number	O
of	O
sublevel-directories	O
is	O
31998	O
,	O
due	O
to	O
the	O
link-count	O
limit	O
.	O
</s>
<s>
Directory	B-Application
indexing	O
is	O
not	O
available	O
in	O
ext2	O
,	O
so	O
there	O
are	O
performance	O
issues	O
for	O
directories	B-Application
with	O
a	O
large	O
number	O
of	O
files	B-Operating_System
(	O
>10	O
,	O
000	O
)	O
.	O
</s>
<s>
The	O
theoretical	O
limit	O
on	O
the	O
number	O
of	O
files	B-Operating_System
in	O
a	O
directory	B-Application
is	O
1.3	O
×	O
1020	O
,	O
although	O
this	O
is	O
not	O
relevant	O
for	O
practical	O
situations	O
.	O
</s>
<s>
Note	O
:	O
In	O
Linux	B-Operating_System
2.4	I-Operating_System
and	O
earlier	O
,	O
block	B-General_Concept
devices	O
were	O
limited	O
to	O
2TiB	O
,	O
limiting	O
the	O
maximal	O
size	O
of	O
a	O
partition	O
,	O
regardless	O
of	O
block	B-General_Concept
size	I-General_Concept
.	O
</s>
<s>
e2compr	B-General_Concept
is	O
a	O
modification	O
to	O
the	O
ext2	O
driver	O
in	O
the	O
Linux	B-Operating_System
kernel	I-Operating_System
to	O
support	O
compression	O
and	O
decompression	O
of	O
files	B-Operating_System
by	O
the	O
file	B-Application
system	I-Application
,	O
without	O
any	O
support	O
by	O
user	O
applications	O
.	O
</s>
<s>
e2compr	B-General_Concept
is	O
a	O
small	O
patch	O
against	O
ext2	O
.	O
</s>
<s>
e2compr	B-General_Concept
compresses	O
only	O
regular	O
files	B-Operating_System
;	O
the	O
administrative	O
data	O
(	O
superblock	O
,	O
inodes	B-Application
,	O
directory	B-Application
files	B-Operating_System
,	O
etc	O
.	O
)	O
</s>
<s>
Access	O
to	O
compressed	O
blocks	B-General_Concept
is	O
provided	O
for	O
read	O
and	O
write	O
operations	O
.	O
</s>
<s>
The	O
compression	B-General_Concept
algorithm	I-General_Concept
and	O
cluster	O
size	O
is	O
specified	O
on	O
a	O
per-file	O
basis	O
.	O
</s>
<s>
Directories	B-Application
can	O
also	O
be	O
marked	O
for	O
compression	O
,	O
in	O
which	O
case	O
every	O
newly	O
created	O
file	O
in	O
the	O
directory	B-Application
will	O
be	O
automatically	O
compressed	O
with	O
the	O
same	O
cluster	O
size	O
and	O
the	O
same	O
algorithm	O
that	O
was	O
specified	O
for	O
the	O
directory	B-Application
.	O
</s>
<s>
e2compr	B-General_Concept
is	O
not	O
a	O
new	O
file	B-Application
system	I-Application
.	O
</s>
<s>
It	O
does	O
not	O
require	O
user	O
to	O
make	O
a	O
new	O
partition	O
,	O
and	O
will	O
continue	O
to	O
read	O
or	O
write	O
existing	O
ext2	O
file	B-Application
systems	I-Application
.	O
</s>
<s>
One	O
can	O
consider	O
it	O
as	O
simply	O
a	O
way	O
for	O
the	O
read	O
and	O
write	O
routines	O
to	O
access	O
files	B-Operating_System
that	O
could	O
have	O
been	O
created	O
by	O
a	O
simple	O
utility	O
similar	O
to	O
gzip	O
or	O
compress	O
.	O
</s>
<s>
Compressed	O
and	O
uncompressed	B-General_Concept
files	B-Operating_System
coexist	O
nicely	O
on	O
ext2	O
partitions	O
.	O
</s>
<s>
The	O
latest	O
e2compr-branch	O
is	O
available	O
for	O
current	O
releases	O
of	O
Linux	B-Operating_System
2.4	I-Operating_System
,	O
2.6	O
,	O
and	O
3.0	O
.	O
</s>
<s>
The	O
latest	O
patch	O
for	O
Linux	B-Operating_System
3.0	O
was	O
released	O
in	O
August	O
2011	O
and	O
provides	O
multicore	B-Operating_System
and	O
High	B-Application
memory	I-Application
support	O
.	O
</s>
<s>
There	O
are	O
also	O
branches	O
for	O
Linux	B-Operating_System
2.0	O
and	O
2.2	O
.	O
</s>
<s>
Access	O
to	O
ext2	O
partitions	O
under	O
Microsoft	B-Application
Windows	I-Application
is	O
possible	O
through	O
an	O
Installable	B-Application
File	I-Application
System	I-Application
,	O
such	O
as	O
ext2ifs	O
or	O
ext2Fsd	B-Language
.	O
</s>
<s>
Filesystem	B-Application
in	I-Application
Userspace	I-Application
can	O
be	O
used	O
on	O
macOS	B-Application
.	O
</s>
