<s>
The	O
Amiga	B-Device
Fast	I-Device
File	I-Device
System	I-Device
(	O
abbreviated	O
AFFS	O
,	O
or	O
more	O
commonly	O
historically	O
as	O
FFS	O
)	O
is	O
a	O
file	B-Application
system	I-Application
used	O
on	O
the	O
Amiga	B-Device
personal	B-Device
computer	I-Device
.	O
</s>
<s>
The	O
previous	O
Amiga	B-Device
filesystem	B-Application
was	O
never	O
given	O
a	O
specific	O
name	O
and	O
known	O
originally	O
simply	O
as	O
"	O
DOS	O
"	O
or	O
AmigaDOS	O
.	O
</s>
<s>
Upon	O
the	O
release	O
of	O
FFS	O
,	O
the	O
original	O
filesystem	B-Application
became	O
known	O
as	O
Amiga	B-Application
Old	I-Application
File	I-Application
System	I-Application
(	O
OFS	B-Application
)	O
.	O
</s>
<s>
OFS	B-Application
,	O
which	O
was	O
primarily	O
designed	O
for	O
use	O
with	O
floppy	O
disks	O
,	O
had	O
been	O
proving	O
slow	O
to	O
keep	O
up	O
with	O
hard	O
drives	O
of	O
the	O
era	O
.	O
</s>
<s>
FFS	O
was	O
designed	O
as	O
a	O
full	O
replacement	O
for	O
the	O
original	O
Amiga	B-Device
filesystem	B-Application
.	O
</s>
<s>
Data	O
blocks	O
contain	O
nothing	O
but	O
data	O
,	O
allowing	O
the	O
filesystem	B-Application
to	O
manage	O
the	O
transfer	O
of	O
large	O
chunks	O
of	O
data	O
directly	O
from	O
the	O
host	B-Architecture
adapter	I-Architecture
to	O
the	O
final	O
destination	O
.	O
</s>
<s>
OFS	B-Application
was	O
the	O
predecessor	O
to	O
FFS	O
.	O
</s>
<s>
Before	O
FFS	O
was	O
released	O
,	O
AmigaOS	B-Application
had	O
a	O
single	O
filesystem	B-Application
simply	O
called	O
AmigaDOS	O
:	O
this	O
uses	O
24	O
bytes	O
per	O
sector	O
for	O
redundancy	O
data	O
,	O
providing	O
for	O
reconstructing	O
structural	O
data	O
on	O
less	O
reliable	O
media	O
such	O
as	O
floppy	O
disks	O
.	O
</s>
<s>
hard	O
disks	O
)	O
became	O
more	O
available	O
to	O
the	O
Amiga	B-Device
,	O
this	O
redundant	O
data	O
posed	O
a	O
bottleneck	O
as	O
all	O
data	O
needed	O
to	O
be	O
realigned	O
to	O
be	O
passed	O
to	O
the	O
application	O
.	O
</s>
<s>
The	O
previous	O
filesystem	B-Application
,	O
AmigaDOS	O
,	O
was	O
renamed	O
OFS	B-Application
,	O
Old	O
File	B-Application
System	I-Application
,	O
to	O
differentiate	O
between	O
it	O
and	O
FFS	O
.	O
</s>
<s>
FFS	O
was	O
backward-compatible	O
and	O
could	O
access	O
devices	O
formatted	O
with	O
OFS	B-Application
.	O
</s>
<s>
Given	O
these	O
advantages	O
,	O
FFS	O
was	O
rapidly	O
adopted	O
as	O
the	O
most	O
common	O
filesystem	B-Application
used	O
by	O
almost	O
all	O
Amiga	B-Device
users	O
,	O
although	O
OFS	B-Application
continued	O
to	O
be	O
widely	O
used	O
on	O
floppy	O
disks	O
from	O
third-party	O
software	O
vendors	O
.	O
</s>
<s>
(	O
This	O
was	O
purely	O
for	O
compatibility	O
with	O
pre-AmigaOS	O
2	O
systems	O
in	O
games	O
and	O
applications	O
that	O
did	O
not	O
actually	O
require	O
AmigaOS	B-Application
2+	O
,	O
as	O
machines	O
running	O
earlier	O
versions	O
of	O
the	O
OS	O
without	O
FFS	O
in	O
the	O
ROM	O
could	O
not	O
boot	O
from	O
these	O
floppies	O
,	O
although	O
they	O
could	O
still	O
read	O
them	O
if	O
they	O
had	O
FFS	O
installed	O
.	O
)	O
</s>
<s>
Amiga	B-Device
FFS	I-Device
is	O
simple	O
and	O
efficient	O
,	O
and	O
when	O
introduced	O
was	O
more	O
than	O
adequate	O
,	O
and	O
had	O
many	O
advantages	O
compared	O
to	O
the	O
file	B-Application
systems	I-Application
of	O
other	O
platforms	O
.	O
</s>
<s>
However	O
,	O
as	O
OFS	B-Application
had	O
done	O
before	O
it	O
,	O
it	O
aged	O
;	O
as	O
drives	O
became	O
larger	O
and	O
the	O
number	O
of	O
files	O
on	O
them	O
increased	O
,	O
its	O
use	O
as	O
a	O
day-to-day	O
filesystem	B-Application
became	O
more	O
problematic	O
in	O
terms	O
of	O
difficulty	O
of	O
maintenance	O
and	O
competitiveness	O
of	O
general	O
performance	O
.	O
</s>
<s>
Despite	O
this	O
,	O
it	O
is	O
still	O
used	O
on	O
AmigaOS	B-Application
systems	O
and	O
shipped	O
with	O
both	O
MorphOS	B-Operating_System
and	O
AmigaOS	B-Application
4	I-Application
.	O
</s>
<s>
By	O
the	O
last	O
Commodore	O
release	O
of	O
AmigaOS	B-Application
,	O
3.1	O
,	O
FFS	O
was	O
still	O
the	O
only	O
filesystem	B-Application
shipped	O
as	O
standard	O
with	O
the	O
Amiga	B-Device
,	O
but	O
it	O
was	O
already	O
showing	O
its	O
age	O
as	O
technology	O
advanced	O
.	O
</s>
<s>
FFS	O
(	O
and	O
OFS	B-Application
)	O
stores	O
a	O
"	O
bitmap	O
"	O
of	O
the	O
filesystem	B-Application
in	O
a	O
single	O
sector	O
.	O
</s>
<s>
This	O
resembled	O
a	O
very	O
simple	O
form	O
of	O
filesystem	B-Application
journaling	I-Application
.	O
</s>
<s>
To	O
allow	O
the	O
disk	O
to	O
be	O
used	O
again	O
with	O
an	O
invalidated	O
OFS	B-Application
or	O
FFS	O
filesystem	B-Application
,	O
the	O
entire	O
disk	O
has	O
to	O
be	O
completely	O
scanned	O
and	O
the	O
bitmap	O
rebuilt	O
,	O
but	O
only	O
the	O
data	O
being	O
modified	O
during	O
the	O
write	O
would	O
be	O
lost	O
.	O
</s>
<s>
AmigaOS	B-Application
originally	O
included	O
a	O
disk-validator	O
on	O
every	O
bootable	O
disk	O
,	O
which	O
was	O
prone	O
to	O
being	O
replaced	O
by	O
viruses	O
to	O
allow	O
themselves	O
to	O
spread	O
(	O
for	O
example	O
the	O
"	O
Saddam	O
Hussein	O
"	O
virus	O
)	O
.	O
</s>
<s>
In	O
terms	O
of	O
support	O
tools	O
,	O
although	O
Commodore	O
itself	O
only	O
shipped	O
with	O
an	O
application	O
called	O
DiskDoctor	O
(	O
and	O
later	O
removed	O
it	O
from	O
AmigaOS	B-Application
disks	O
)	O
,	O
FFS	O
had	O
a	O
small	O
selection	O
of	O
third-party	O
tools	O
—	O
most	O
notably	O
DiskSalv	O
—	O
to	O
maintain	O
the	O
file	B-Application
system	I-Application
and	O
repair	O
and	O
validate	O
it	O
,	O
undelete	O
files	O
,	O
or	O
reverse	O
"	O
quick	O
formats	O
"	O
(	O
filesystem	B-Application
initializations	O
)	O
.	O
</s>
<s>
An	O
OFS	B-Application
or	O
FFS	O
volume	O
had	O
to	O
be	O
locked	O
to	O
defragment	O
or	O
convert	O
to	O
different	O
FFS	O
modes	O
to	O
prevent	O
corruption	O
and	O
this	O
made	O
it	O
inaccessible	O
to	O
everything	O
but	O
the	O
tool	O
defragmenting	O
it	O
.	O
</s>
<s>
When	O
hard	O
drives	O
in	O
use	O
by	O
Amiga	B-Device
users	O
were	O
reaching	O
4	O
GB	O
in	O
size	O
,	O
this	O
became	O
a	O
problem	O
.	O
</s>
<s>
For	O
all	O
of	O
these	O
reasons	O
,	O
FFS	O
was	O
often	O
replaced	O
by	O
users	O
in	O
the	O
mid-1990s	O
with	O
more	O
up-to-date	O
alternatives	O
such	O
as	O
Smart	B-Application
File	I-Application
System	I-Application
(	O
SFS	O
)	O
and	O
Professional	B-Application
File	I-Application
System	I-Application
(	O
PFS	O
)	O
,	O
which	O
did	O
not	O
have	O
these	O
limitations	O
and	O
were	O
considered	O
safer	O
,	O
faster	O
and	O
more	O
efficient	O
.	O
</s>
<s>
SFS	O
in	O
particular	O
continued	O
to	O
be	O
developed	O
and	O
is	O
now	O
as	O
close	O
to	O
a	O
generic	O
AmigaOS	B-Application
filesystem	B-Application
as	O
FFS	O
.	O
</s>
<s>
FFS	O
was	O
introduced	O
with	O
version	O
1.3	O
of	O
AmigaOS	B-Application
in	O
1988	O
,	O
and	O
replaced	O
both	O
the	O
Kickstart	O
ROM	O
(	O
or	O
Kickstart	O
floppy	O
for	O
A1000s	O
)	O
and	O
Workbench	O
floppy	O
with	O
updated	O
software	O
.	O
</s>
<s>
It	O
carried	O
the	O
version	O
number	O
of	O
v34	O
,	O
like	O
the	O
rest	O
of	O
the	O
AmigaOS	B-Application
1.3	O
components	O
.	O
</s>
<s>
Workbench	O
1.3	O
provided	O
the	O
FFS	O
filesystem	B-Application
device	O
driver	O
on	O
disk	O
,	O
which	O
could	O
be	O
copied	O
into	O
the	O
Rigid	B-Application
Disk	I-Application
Block	I-Application
(	O
RDB	O
)	O
on	O
hard	O
disks	O
.	O
</s>
<s>
Compliant	O
block	O
devices	O
would	O
then	O
load	O
and	O
install	O
the	O
filesystem	B-Application
driver	O
before	O
filesystems	B-Application
were	O
mounted	O
and	O
thus	O
make	O
it	O
possible	O
to	O
use	O
loadable	O
filesystems	B-Application
on	O
hard	O
disks	O
.	O
</s>
<s>
FFS	O
support	O
was	O
merged	O
into	O
the	O
ROM-based	O
filesystem	B-Application
from	O
Kickstart	O
2.0	O
onwards	O
,	O
and	O
so	O
it	O
was	O
no	O
longer	O
necessary	O
to	O
install	O
FFS	O
in	O
the	O
RDB	O
.	O
</s>
<s>
The	O
ability	O
to	O
load	O
filesystems	B-Application
from	O
the	O
RDB	O
still	O
remained	O
available	O
in	O
case	O
one	O
wished	O
to	O
fix	O
ROM	O
bugs	O
,	O
get	O
new	O
FFS	O
features	O
,	O
or	O
use	O
a	O
third-party	O
filesystem	B-Application
.	O
</s>
<s>
Floppies	O
are	O
unpartitioned	O
devices	O
without	O
a	O
RDB	O
and	O
also	O
do	O
not	O
use	O
the	O
autobooting	O
mechanism	O
,	O
so	O
were	O
only	O
bootable	O
if	O
the	O
disk	O
's	O
dostype	O
was	O
one	O
the	O
ROM-based	O
filesystem	B-Application
understood	O
.	O
</s>
<s>
The	O
various	O
FFS	O
flavours	O
did	O
not	O
have	O
any	O
compatibility	O
problems	O
with	O
Amiga	B-Device
software	O
,	O
even	O
ones	O
that	O
were	O
considered	O
"	O
system-unfriendly	O
"	O
.	O
</s>
<s>
Software	O
would	O
either	O
use	O
the	O
system	O
calls	O
and	O
thus	O
work	O
with	O
any	O
filesystem	B-Application
,	O
or	O
be	O
"	O
trackloaders	O
"	O
and	O
not	O
use	O
a	O
filesystem	B-Application
at	O
all	O
.	O
</s>
<s>
AmigaOS	B-Application
filesystems	B-Application
are	O
identified	O
by	O
a	O
four	O
letter	O
descriptor	O
which	O
is	O
specified	O
either	O
in	O
the	O
RDB	O
or	O
a	O
mountlist	O
or	O
dosdriver	O
;	O
alternatively	O
(	O
as	O
was	O
the	O
case	O
in	O
trackdisk-like	O
devices	O
like	O
floppy	O
disks	O
)	O
,	O
the	O
disk	O
itself	O
could	O
be	O
formatted	O
in	O
any	O
dostype	O
specified	O
.	O
</s>
<s>
DOS	O
\0	O
:	O
The	O
original	O
Amiga	B-Device
filesystem	B-Application
(	O
OFS	B-Application
)	O
.	O
</s>
<s>
This	O
was	O
left	O
in	O
for	O
compatibility	O
purposes	O
,	O
and	O
the	O
majority	O
floppy	O
disks	O
shipped	O
by	O
software	O
companies	O
or	O
as	O
magazine	O
coverdisks	O
used	O
this	O
dostype	O
so	O
that	O
they	O
would	O
boot	O
on	O
pre-2.x	O
machines	O
like	O
the	O
Amiga	B-Device
500	O
.	O
</s>
<s>
It	O
also	O
meant	O
that	O
users	O
with	O
existing	O
OFS-formatted	O
drives	O
could	O
read	O
them	O
once	O
they	O
had	O
installed	O
FFS	O
to	O
the	O
RDB	O
.	O
</s>
<s>
DOS	O
\1	O
:	O
The	O
new	O
filesystem	B-Application
,	O
FFS	O
.	O
</s>
<s>
AmigaOS	B-Application
2.04	O
made	O
FFS	O
(	O
now	O
v37	O
)	O
part	O
of	O
the	O
Kickstart	O
ROM	O
and	O
introduced	O
new	O
modes	O
for	O
handling	O
international	O
characters	O
in	O
filenames	O
,	O
and	O
for	O
an	O
on-disk	O
directory	O
cache	O
.	O
</s>
<s>
Each	O
new	O
mode	O
was	O
available	O
with	O
both	O
OFS	B-Application
and	O
FFS	O
dostypes	O
.	O
</s>
<s>
This	O
odd	O
system	O
was	O
for	O
parity	O
:	O
OFS	B-Application
modes	O
apart	O
from	O
DOS	O
\0	O
were	O
almost	O
never	O
used	O
but	O
were	O
available	O
nonetheless	O
.	O
</s>
<s>
(	O
Although	O
OFS	B-Application
,	O
they	O
were	O
still	O
not	O
compatible	O
with	O
Amiga	B-Device
systems	O
without	O
FFS	O
)	O
.	O
</s>
<s>
DOS	O
\2	O
:	O
"	O
International	O
"	O
(	O
OFS-INTL	O
)	O
mode	O
allows	O
OFS	B-Application
to	O
handle	O
filenames	O
with	O
"	O
international	O
characters	O
"	O
-	O
i.e.	O
</s>
<s>
DOS	O
\4	O
:	O
"	O
Directory	O
Cache	O
"	O
(	O
OFS-DC	O
)	O
mode	O
enabled	O
to	O
primitive	O
cache	O
by	O
creating	O
dedicated	O
directory	O
lists	O
instead	O
of	O
having	O
to	O
pick	O
up	O
the	O
linked	O
directory/file	O
entries	O
that	O
lie	O
scattered	O
over	O
the	O
disk	O
.	O
</s>
<s>
It	O
became	O
a	O
popular	O
choice	O
on	O
Amiga	B-Device
hard	O
drives	O
,	O
but	O
according	O
to	O
Olaf	O
Barthel	O
,	O
author	O
of	O
FFS2	O
,	O
the	O
use	O
of	O
dircache	O
modes	O
was	O
probably	O
better	O
for	O
floppy	O
disks	O
than	O
it	O
was	O
for	O
hard	O
drives	O
,	O
where	O
it	O
would	O
cause	O
an	O
overall	O
degradation	O
in	O
performance	O
compared	O
to	O
lack	O
of	O
dircache	O
.	O
</s>
<s>
Version	O
40.1	O
was	O
the	O
last	O
version	O
of	O
FFS	O
released	O
by	O
Commodore	O
,	O
and	O
came	O
with	O
AmigaOS	B-Application
3.1	O
,	O
both	O
on	O
the	O
OS	O
disks	O
and	O
in	O
the	O
ROM	O
.	O
</s>
<s>
After	O
this	O
,	O
several	O
Unofficial	O
patches	O
appeared	O
which	O
allowed	O
its	O
use	O
on	O
drives	O
after	O
the	O
first	O
2GB	O
of	O
a	O
hard	O
disk	O
using	O
a	O
64-bit	O
addressing	O
system	O
called	O
TrackDisk64	O
or	O
TD64	O
(	O
although	O
the	O
2	B-Application
GB	I-Application
limit	I-Application
on	O
file	O
size	O
and	O
the	O
127GB	O
limit	O
on	O
partition	O
sizes	O
remained	O
,	O
as	O
it	O
was	O
a	O
limitation	O
of	O
AmigaOS	B-Application
dos.library	O
and	O
all	O
then-current	O
Amiga	B-Device
software	O
)	O
and	O
carried	O
the	O
version	O
number	O
of	O
v44	O
.	O
</s>
<s>
The	O
version	O
of	O
FFS	O
that	O
came	O
with	O
AmigaOS	B-Application
3.5	O
and	O
3.9	O
was	O
v45	O
and	O
differed	O
in	O
that	O
it	O
used	O
a	O
different	O
64-bit	O
addressing	O
system	O
,	O
New	O
Style	O
Device	O
or	O
NSD	O
.	O
</s>
<s>
More	O
recently	O
(	O
from	O
2003	O
)	O
,	O
MorphOS	B-Operating_System
and	O
AmigaOS	B-Application
4	I-Application
have	O
introduced	O
support	O
for	O
a	O
slightly	O
updated	O
"	O
FFS2	O
"	O
,	O
by	O
Olaf	O
Barthel	O
(	O
FFS	O
v46	O
,	O
v50	O
respectively	O
)	O
.	O
</s>
<s>
It	O
is	O
PowerPC	B-Architecture
native	O
,	O
and	O
introduced	O
two	O
more	O
dostypes	O
(	O
which	O
are	O
not	O
capable	O
of	O
being	O
read	O
by	O
the	O
older	O
FFS	O
)	O
:	O
</s>
<s>
DOS	O
\6	O
:	O
"	O
Long	O
Filename	O
"	O
(	O
OFS-LNFS	O
)	O
.	O
</s>
<s>
This	O
allowed	O
files	O
to	O
have	O
a	O
longer	O
filename	O
(	O
up	O
to	O
107	O
characters	O
)	O
than	O
the	O
usual	O
Amiga	B-Device
limit	O
,	O
which	O
was	O
31	O
characters	O
.	O
</s>
<s>
Despite	O
the	O
ability	O
to	O
use	O
the	O
long	O
filenames	O
,	O
by	O
this	O
time	O
FFS	O
compared	O
very	O
poorly	O
to	O
other	O
available	O
filesystems	B-Application
on	O
the	O
platforms	O
it	O
was	O
available	O
for	O
.	O
</s>
<s>
In	O
September	O
2018	O
,	O
Hyperion	O
Entertainment	O
released	O
Amiga	B-Application
OS	I-Application
3.1.4	O
from	O
the	O
Amiga	B-Application
OS	I-Application
3.1	O
source	O
.	O
</s>
<s>
This	O
lets	O
the	O
Amiga	B-Application
OS	I-Application
v3.x	O
use	O
and	O
boot	O
from	O
large	O
media	O
(	O
>4GB	O
)	O
natively	O
,	O
and	O
support	O
>2GB	O
partition	O
sizes	O
.	O
</s>
<s>
In	O
May	O
2021	O
,	O
an	O
updated	O
Amiga	B-Application
OS	I-Application
3.2	O
was	O
released	O
and	O
provided	O
a	O
matching	O
ROM-based	O
V47	O
FFS	O
update	O
which	O
gained	O
a	O
few	O
minor	O
features	O
and	O
fixes	O
.	O
</s>
<s>
There	O
were	O
few	O
other	O
implementations	O
which	O
are	O
able	O
to	O
read	O
FFS	O
filesystems	B-Application
,	O
which	O
would	O
normally	O
require	O
an	O
Amiga	B-Device
emulator	O
and	O
a	O
copy	O
of	O
the	O
operating	O
system	O
ROMs	O
to	O
be	O
read	O
.	O
</s>
<s>
Most	O
notably	O
,	O
support	O
for	O
affs	O
(	O
Amiga	B-Device
Fast	I-Device
File	I-Device
System	I-Device
)	O
can	O
be	O
compiled	O
into	O
Linux	O
kernels	O
,	O
and	O
offers	O
full	O
read	O
,	O
write	O
and	O
format	O
support	O
on	O
FFS	O
and	O
OFS	B-Application
partitions	O
of	O
all	O
dostypes	O
except	O
DOS	O
\6	O
and	O
DOS	O
\7	O
(	O
which	O
are	O
probably	O
incredibly	O
rare	O
)	O
.	O
</s>
<s>
On	O
the	O
Amiga	B-Device
,	O
the	O
freeware	O
application	O
xfs	O
could	O
,	O
among	O
many	O
filesystems	B-Application
,	O
read	O
and	O
write	O
to	O
devices	O
formatted	O
in	O
OFS	B-Application
or	O
FFS	O
,	O
and	O
was	O
probably	O
the	O
sole	O
Amiga	B-Device
filesystem	B-Application
apart	O
from	O
FFS/FFS2	O
itself	O
to	O
do	O
so	O
.	O
</s>
