<s>
Large-file	B-Application
support	I-Application
(	O
LFS	O
)	O
is	O
the	O
term	O
frequently	O
applied	O
to	O
the	O
ability	O
to	O
create	O
files	O
larger	O
than	O
either	O
2	O
or	O
4GiB	O
on	O
32-bit	O
filesystems	B-Application
.	O
</s>
<s>
Traditionally	O
,	O
many	O
operating	O
systems	O
and	O
their	O
underlying	O
file	B-Application
system	I-Application
implementations	O
used	O
32-bit	O
integers	O
to	O
represent	O
file	B-General_Concept
sizes	I-General_Concept
and	O
positions	O
.	O
</s>
<s>
Consequently	O
,	O
no	O
file	B-Operating_System
could	O
be	O
larger	O
than	O
232	O
−	O
1	O
bytes	O
(	O
4	O
GiB	O
−	O
1	O
)	O
.	O
</s>
<s>
While	O
the	O
limit	O
was	O
quite	O
acceptable	O
at	O
a	O
time	O
when	O
hard	B-Device
disks	I-Device
were	O
smaller	O
,	O
the	O
general	O
increase	O
in	O
storage	O
capacity	O
combined	O
with	O
increased	O
server	O
and	O
desktop	O
file	B-Operating_System
usage	O
,	O
especially	O
for	O
database	O
and	O
multimedia	O
files	O
,	O
led	O
to	O
intense	O
pressure	O
for	O
OS	O
vendors	O
to	O
overcome	O
the	O
limitation	O
.	O
</s>
<s>
In	O
1996	O
,	O
multiple	O
vendors	O
responded	O
by	O
forming	O
an	O
industry	O
initiative	O
known	O
as	O
the	O
Large	B-Application
File	I-Application
Summit	I-Application
to	O
support	O
large	O
files	O
on	O
POSIX	O
(	O
at	O
the	O
time	O
Windows	O
NT	O
already	O
supported	O
large	O
files	O
on	O
NTFS	B-Application
)	O
,	O
an	O
obvious	O
backronym	O
of	O
"	O
LFS	O
"	O
.	O
</s>
<s>
The	O
summit	O
was	O
tasked	O
to	O
define	O
a	O
standardized	O
way	O
to	O
switch	O
to	O
64-bit	B-Device
numbers	O
to	O
represent	O
file	B-General_Concept
sizes	I-General_Concept
.	O
</s>
<s>
The	O
change	O
to	O
64-bit	B-Device
file	B-General_Concept
sizes	I-General_Concept
frequently	O
required	O
incompatible	O
changes	O
to	O
file	B-Application
system	I-Application
layout	O
,	O
which	O
meant	O
that	O
large-file	B-Application
support	I-Application
sometimes	O
necessitated	O
a	O
file	B-Application
system	I-Application
change	O
.	O
</s>
<s>
For	O
example	O
,	O
the	O
FAT32	B-Application
file	B-Application
system	I-Application
does	O
not	O
support	O
files	O
larger	O
than	O
4GiB−1	O
(	O
with	O
older	O
applications	O
even	O
only	O
2GiB−1	O
)	O
;	O
the	O
variant	O
FAT32+	B-Application
does	O
support	O
larger	O
files	O
(	O
up	O
to	O
256GiB−1	O
)	O
,	O
but	O
(	O
so	O
far	O
)	O
is	O
only	O
supported	O
in	O
some	O
versions	O
of	O
DR-DOS	B-Application
,	O
so	O
users	O
of	O
Microsoft	B-Application
Windows	I-Application
have	O
to	O
use	O
NTFS	B-Application
or	O
exFAT	B-Application
instead	O
.	O
</s>
<s>
To	O
support	O
binary	O
compatibility	O
with	O
old	O
applications	O
,	O
operating	O
system	O
interfaces	O
had	O
to	O
retain	O
their	O
use	O
of	O
32-bit	O
file	B-General_Concept
sizes	I-General_Concept
and	O
new	O
interfaces	O
had	O
to	O
be	O
designed	O
specifically	O
for	O
large-file	B-Application
support	I-Application
.	O
</s>
<s>
To	O
support	O
writing	O
portable	O
code	O
that	O
makes	O
use	O
of	O
LFS	O
where	O
possible	O
,	O
C	B-Language
standard	I-Language
library	I-Language
authors	O
devised	O
mechanisms	O
that	O
,	O
depending	O
on	O
preprocessor	B-Language
constants	O
,	O
transparently	O
redefined	O
the	O
functions	O
to	O
the	O
64-bit	B-Device
large-file	O
aware	O
ones	O
.	O
</s>
<s>
Many	O
old	O
interfaces	O
,	O
especially	O
C-based	O
ones	O
,	O
explicitly	O
specified	O
argument	O
types	O
in	O
a	O
way	O
that	O
did	O
not	O
allow	O
straightforward	O
or	O
transparent	O
transition	O
to	O
64-bit	B-Device
types	O
.	O
</s>
<s>
For	O
example	O
,	O
the	O
C	B-Language
functions	I-Language
fseek	O
and	O
ftell	O
operate	O
on	O
file	B-Operating_System
positions	O
of	O
type	O
long	O
int	O
,	O
which	O
is	O
typically	O
32	O
bits	O
wide	O
on	O
32-bit	O
platforms	O
,	O
and	O
cannot	O
be	O
made	O
larger	O
without	O
sacrificing	O
backward	O
compatibility	O
.	O
</s>
<s>
On	O
Windows	O
machines	O
,	O
under	O
Visual	O
C++	O
,	O
functions	O
_fseeki64	O
and	O
_ftelli64	O
are	O
used	O
.	O
)	O
</s>
<s>
The	O
usage	O
of	O
the	O
large-file	O
API	B-Application
in	O
32-bit	O
programs	O
had	O
been	O
incomplete	O
for	O
a	O
long	O
time	O
.	O
</s>
<s>
An	O
analysis	O
did	O
show	O
in	O
2002	O
that	O
many	O
base	O
libraries	O
of	O
operating	O
systems	O
were	O
still	O
shipped	O
without	O
large-file	B-Application
support	I-Application
thereby	O
limiting	O
applications	O
using	O
them	O
.	O
</s>
<s>
The	O
much-used	O
zlib	B-Language
library	O
started	O
to	O
support	O
64-bit	B-Device
large-files	O
on	O
32-bit	O
platform	O
not	O
before	O
2006	O
.	O
</s>
<s>
The	O
problem	O
disappeared	O
slowly	O
with	O
PCs	O
and	O
workstations	O
moving	O
completely	O
to	O
64-bit	B-Device
computing	I-Device
.	O
</s>
<s>
Microsoft	B-Application
Windows	I-Application
Server	O
2008	O
has	O
been	O
the	O
last	O
server	O
version	O
to	O
be	O
shipped	O
in	O
32-bit	O
.	O
</s>
<s>
Redhat	O
Enterprise	O
Linux	B-Operating_System
7	O
was	O
published	O
in	O
2014	O
only	O
as	O
a	O
64-bit	B-Device
operating	O
system	O
.	O
</s>
<s>
Ubuntu	O
Linux	B-Operating_System
stopped	O
delivering	O
a	O
32-bit	O
variant	O
in	O
2019	O
.	O
</s>
<s>
Apple	O
stopped	O
developing	O
32-bit	O
Mac	O
OS	O
versions	O
in	O
2018	O
delivering	O
macOS	B-Device
Mojave	I-Device
only	O
as	O
a	O
64-bit	B-Device
operating	O
system	O
.	O
</s>
<s>
Windows	B-Application
11	I-Application
however	O
will	O
ship	O
only	O
as	O
a	O
64-bit	B-Device
operating	O
system	O
since	O
its	O
first	O
version	O
in	O
2021	O
.	O
</s>
<s>
Google	O
required	O
to	O
support	O
64-bit	B-Device
versions	O
of	O
applications	O
in	O
their	O
app	B-Application
store	O
by	O
August	O
2019	O
,	O
which	O
allows	O
to	O
discontinue	O
32-bit	O
support	O
for	O
Android	B-Application
later	O
.	O
</s>
<s>
The	O
shift	O
towards	O
64-bit	B-Device
started	O
in	O
2014	O
when	O
all	O
new	O
processors	O
were	O
designed	O
to	O
a	O
64-bit	B-Device
architecture	I-Device
and	O
Android	B-Application
5	I-Application
(	O
"	O
Lollipop	B-Application
"	O
)	O
was	O
published	O
in	O
that	O
year	O
providing	O
a	O
fitting	O
64-bit	B-Device
variant	O
of	O
the	O
operating	O
system	O
.	O
</s>
<s>
Apple	O
had	O
made	O
shift	O
in	O
the	O
year	O
before	O
starting	O
to	O
produce	O
the	O
64-Bit	B-Device
Apple	O
A7	O
by	O
2013	O
.	O
</s>
<s>
Google	O
started	O
to	O
deliver	O
the	O
development	O
environment	O
for	O
Linux	B-Operating_System
only	O
in	O
64-bit	B-Device
by	O
2015	O
.	O
</s>
<s>
In	O
May	O
2019	O
the	O
share	O
of	O
Android	B-Application
versions	O
below	O
5	O
had	O
fallen	O
to	O
ten	O
percent	O
.	O
</s>
<s>
As	O
app	B-Application
developers	O
concentrate	O
on	O
a	O
single	O
compilation	B-Application
variant	O
,	O
many	O
manufacturers	O
started	O
to	O
require	O
Android	B-Application
5	I-Application
as	O
the	O
minimum	O
version	O
by	O
mid	O
2019	O
,	O
for	O
example	O
Niantic	O
.	O
</s>
<s>
Except	O
for	O
embedded	B-Architecture
systems	I-Architecture
with	O
their	O
special	O
programs	O
,	O
the	O
consideration	O
of	O
varying	O
large-file	B-Application
support	I-Application
becomes	O
obsolete	O
in	O
program	O
code	O
after	O
2020	O
.	O
</s>
<s>
The	O
year	B-Application
2038	I-Application
problem	I-Application
is	O
well	O
known	O
for	O
another	O
case	O
where	O
a	O
32-bit	O
"	O
long	O
"	O
on	O
32-bit	O
platforms	O
will	O
lead	O
into	O
problems	O
.	O
</s>
<s>
Just	O
like	O
the	O
large-file	O
limitation	O
it	O
will	O
get	O
obsolete	O
when	O
systems	O
move	O
to	O
64-bit	B-Device
only	O
.	O
</s>
<s>
In	O
the	O
meantime	O
a	O
64-bit	B-Device
timestamp	O
was	O
introduced	O
.	O
</s>
<s>
In	O
the	O
Win32	O
API	B-Application
it	O
is	O
visible	O
in	O
functions	O
having	O
a	O
"	O
64	O
"	O
suffix	O
along	O
the	O
earlier	O
"	O
32	O
"	O
suffix	O
.	O
</s>
<s>
When	O
large-file	B-Application
support	I-Application
was	O
added	O
to	O
the	O
Win32	O
API	B-Application
it	O
has	O
led	O
to	O
functions	O
having	O
an	O
additional	O
"	O
i64	O
"	O
suffix	O
which	O
sometimes	O
makes	O
for	O
four	O
combinations	O
.	O
</s>
<s>
By	O
comparison	O
the	O
UNIX98	O
API	B-Application
introduces	O
functions	O
with	O
a	O
"	O
64	O
"	O
suffix	O
when	O
"	O
_LARGEFILE64_SOURCE	O
"	O
is	O
used	O
.	O
</s>
<s>
Related	O
to	O
the	O
large-file	O
API	B-Application
there	O
is	O
a	O
limitation	O
of	O
block	O
numbers	O
for	O
mass	B-Device
storage	I-Device
media	O
.	O
</s>
<s>
With	O
a	O
common	O
size	O
of	O
512	O
bytes	O
per	O
data	B-General_Concept
block	I-General_Concept
the	O
barrier	O
resulting	O
from	O
32-bit	O
numbers	O
did	O
occur	O
later	O
.	O
</s>
<s>
When	O
hard	B-Device
disk	I-Device
drives	I-Device
reached	O
a	O
size	O
of	O
2	O
terabyte	O
(	O
around	O
2010	O
)	O
the	O
master	B-Device
boot	I-Device
record	I-Device
had	O
to	O
be	O
replaced	O
by	O
the	O
GUID	B-Application
Partition	I-Application
Table	I-Application
which	O
uses	O
64-bit	B-Device
for	O
the	O
LBA	O
numbers	O
(	O
logical	B-Device
block	I-Device
address	I-Device
)	O
.	O
</s>
<s>
On	O
Unix-like	B-Operating_System
operating	I-Operating_System
systems	I-Operating_System
it	O
did	O
also	O
require	O
to	O
enlarge	O
the	O
inode	B-Application
numbers	I-Application
which	O
are	O
used	O
in	O
some	O
functions	O
(	O
stat64	O
,	O
setrlimit64	O
)	O
.	O
</s>
<s>
The	O
Linux	B-Operating_System
kernel	I-Operating_System
introduced	O
that	O
in	O
2001	O
leading	O
to	O
version	O
2.4	O
which	O
was	O
picked	O
up	O
by	O
the	O
glibc	B-Language
in	O
that	O
year	O
.	O
</s>
<s>
As	O
the	O
large-file	B-Application
support	I-Application
and	O
large-disk	O
support	O
was	O
introduced	O
at	O
the	O
same	O
time	O
the	O
GNU	B-Language
C	I-Language
Library	I-Language
exports	O
64-bit	B-Device
inode	B-Application
structures	O
on	O
32-bit	O
architectures	O
at	O
the	O
same	O
time	O
when	O
the	O
Unix	O
LFS	O
API	B-Application
is	O
activated	O
in	O
program	O
code	O
.	O
</s>
<s>
When	O
the	O
kernel	B-Operating_System
moved	O
to	O
64-bit	B-Device
inodes	B-Application
the	O
file	B-Application
system	I-Application
ext3	B-Application
used	O
them	O
internally	O
in	O
the	O
driver	O
by	O
2001	O
.	O
</s>
<s>
However	O
the	O
inode	B-Application
format	O
on	O
the	O
storage	O
media	O
itself	O
was	O
stuck	O
at	O
32-bit	O
numbers	O
.	O
</s>
<s>
As	O
mass	B-Device
storage	I-Device
devices	I-Device
moved	O
to	O
the	O
Advanced	B-Device
Format	I-Device
of	O
4	O
kilobyte	O
per	O
block	O
the	O
actual	O
limit	O
of	O
that	O
file	B-Application
system	I-Application
format	O
is	O
at	O
8	O
or	O
16	O
terabyte	O
.	O
</s>
<s>
Handling	O
larger	O
disk	O
partitions	O
requires	O
the	O
usage	O
of	O
a	O
different	O
file	B-Application
system	I-Application
like	O
XFS	B-Application
which	O
was	O
designed	O
with	O
64-bit	B-Device
inodes	B-Application
from	O
the	O
start	O
allowing	O
for	O
exabyte	O
files	O
and	O
partitions	O
.	O
</s>
<s>
Solid-state	B-Device
drive	I-Device
with	O
32	O
TiB	O
for	O
data	O
centers	O
were	O
available	O
as	O
early	O
as	O
2016	O
with	O
some	O
manufacturers	O
forecasting	O
100	O
TiB	O
SSD	B-Device
by	O
2020	O
.	O
</s>
