<s>
AmigaDOS	B-Operating_System
is	O
the	O
disk	B-Operating_System
operating	I-Operating_System
system	I-Operating_System
of	O
the	O
AmigaOS	B-Application
,	O
which	O
includes	O
file	B-Application
systems	I-Application
,	O
file	O
and	O
directory	O
manipulation	O
,	O
the	O
command-line	B-Application
interface	I-Application
,	O
and	O
file	O
redirection	B-Device
.	O
</s>
<s>
In	O
AmigaOS	B-Application
1.x	O
,	O
AmigaDOS	B-Operating_System
is	O
based	O
on	O
a	O
TRIPOS	B-Operating_System
port	O
by	O
MetaComCo	B-Device
,	O
written	O
in	O
BCPL	B-Language
.	O
</s>
<s>
BCPL	B-Language
does	O
not	O
use	O
native	O
pointers	O
,	O
so	O
the	O
more	O
advanced	O
functionality	O
of	O
the	O
operating	O
system	O
was	O
difficult	O
to	O
use	O
and	O
error-prone	O
.	O
</s>
<s>
The	O
third-party	O
AmigaDOS	B-Operating_System
Resource	O
Project	O
(	O
ARP	O
,	O
formerly	O
the	O
AmigaDOS	B-Operating_System
Replacement	O
Project	O
)	O
,	O
a	O
project	O
begun	O
by	O
Amiga	O
developer	O
Charlie	O
Heath	O
,	O
replaced	O
many	O
of	O
the	O
BCPL	B-Language
utilities	O
with	O
smaller	O
,	O
more	O
sophisticated	O
equivalents	O
written	O
in	O
C	B-Language
and	O
assembler	B-Language
,	O
and	O
provided	O
a	O
wrapper	O
library	O
,	O
arp.library	O
.	O
</s>
<s>
This	O
eliminated	O
the	O
interfacing	O
problems	O
in	O
applications	O
by	O
automatically	O
performing	O
conversions	O
from	O
native	O
pointers	O
(	O
such	O
as	O
those	O
used	O
by	O
C	B-Language
or	O
assembler	B-Language
)	O
to	O
BCPL	B-Language
equivalents	O
and	O
vice	O
versa	O
for	O
all	O
AmigaDOS	B-Operating_System
functions	O
.	O
</s>
<s>
From	O
AmigaOS	B-Application
2.x	O
onwards	O
,	O
AmigaDOS	B-Operating_System
was	O
rewritten	O
in	O
C	B-Language
,	O
retaining	O
1.x	O
compatibility	O
where	O
possible	O
.	O
</s>
<s>
Starting	O
with	O
AmigaOS	B-Application
4	I-Application
,	O
AmigaDOS	B-Operating_System
abandoned	O
its	O
legacy	O
with	O
BCPL	B-Language
.	O
</s>
<s>
Starting	O
from	O
AmigaOS	O
4.1	O
,	O
AmigaDOS	B-Operating_System
has	O
been	O
extended	O
with	O
64-bit	O
file-access	O
support	O
.	O
</s>
<s>
It	O
was	O
developed	O
from	O
a	O
primitive	O
interface	O
in	O
AmigaOS	B-Application
1.1	O
,	O
and	O
became	O
stable	O
with	O
versions	O
1.2	O
and	O
1.3	O
,	O
when	O
it	O
started	O
to	O
be	O
known	O
as	O
AmigaShell	B-Operating_System
and	O
its	O
original	O
handler	O
was	O
replaced	O
by	O
newconsole.handler	O
(	O
NEWCON	O
:	O
)	O
.	O
</s>
<s>
The	O
console	O
has	O
various	O
features	O
that	O
were	O
considered	O
up	O
to	O
date	O
when	O
it	O
was	O
created	O
in	O
1985	O
,	O
like	O
command	O
template	O
help	O
,	O
redirection	B-Device
to	O
null	O
(	O
"	O
NIL	O
:	O
"	O
)	O
,	O
and	O
ANSI	O
color	O
terminal	O
.	O
</s>
<s>
The	O
new	O
console	O
handler	O
–	O
which	O
was	O
implemented	O
in	O
release	O
1.2	O
–	O
allows	O
many	O
more	O
features	O
,	O
such	O
as	O
command	B-Application
history	I-Application
,	O
pipelines	B-Operating_System
,	O
and	O
automatic	O
creation	O
of	O
files	O
when	O
output	O
is	O
redirected	B-Device
.	O
</s>
<s>
When	O
TCP/IP	B-Protocol
stacks	I-Protocol
like	O
AmiTCP	O
were	O
released	O
in	O
the	O
early	O
1990s	O
,	O
the	O
console	O
could	O
also	O
receive	O
redirection	B-Device
from	O
Internet-enabled	O
Amiga	O
device	O
handlers	O
(	O
e.g.	O
,	O
TCP	O
:	O
,	O
)	O
.	O
</s>
<s>
Unlike	O
other	O
systems	O
originally	O
launched	O
in	O
the	O
mid-1980s	O
,	O
AmigaDOS	B-Operating_System
does	O
not	O
implement	O
a	O
proprietary	B-Application
character	O
set	O
;	O
the	O
developers	O
chose	O
to	O
use	O
the	O
ANSI	O
–	O
ISO	O
standard	O
ISO-8859-1	O
(	O
Latin	O
1	O
)	O
,	O
which	O
includes	O
the	O
ASCII	B-Protocol
character	I-Protocol
set	I-Protocol
.	O
</s>
<s>
As	O
in	O
Unix	B-Application
systems	I-Application
,	O
the	O
Amiga	O
console	O
accepts	O
only	O
linefeed	O
(	O
"	O
LF	O
"	O
)	O
as	O
an	O
end-of-line	O
(	O
"	O
EOL	O
"	O
)	O
character	O
.	O
</s>
<s>
This	O
is	O
an	O
example	O
of	O
typical	O
AmigaDOS	B-Operating_System
command	O
syntax	O
:	O
</s>
<s>
AmigaDOS	B-Operating_System
can	O
redirect	O
the	O
output	O
of	O
a	O
command	O
to	O
files	O
,	O
pipes	B-Operating_System
,	O
a	O
printer	O
,	O
the	O
null	O
device	O
,	O
and	O
other	O
Amiga	O
devices	O
.	O
</s>
<s>
The	O
colon	O
character	O
"	O
:	O
"	O
indicates	O
that	O
SPEAK	O
:	O
points	O
to	O
an	O
AmigaDOS	B-Operating_System
device	O
.	O
</s>
<s>
While	O
a	O
typical	O
use	O
for	O
a	O
device	O
is	O
file	B-Application
systems	I-Application
,	O
special-purpose	O
device	O
names	O
such	O
as	O
this	O
are	O
commonly	O
used	O
in	O
the	O
system	O
.	O
</s>
<s>
AmigaDOS	B-Operating_System
commands	O
are	O
expected	O
to	O
provide	O
a	O
standard	O
"	O
template	O
"	O
that	O
describes	O
the	O
arguments	O
they	O
can	O
accept	O
.	O
</s>
<s>
This	O
can	O
be	O
used	O
as	O
a	O
basic	O
"	O
help	O
"	O
feature	O
for	O
commands	O
,	O
although	O
third-party	O
replacement	O
console	O
handlers	O
and	O
shells	O
,	O
such	O
as	O
Bash	B-Operating_System
or	O
Zshell	B-Application
(	O
ported	O
from	O
Unix	B-Application
)	O
,	O
or	O
KingCON	O
often	O
provide	O
more	O
verbose	O
help	O
for	O
built-in	O
commands	O
.	O
</s>
<s>
Like	O
other	O
operating	O
systems	O
,	O
AmigaDOS	B-Operating_System
also	O
provides	O
wildcard	B-Algorithm
characters	I-Algorithm
that	O
are	O
substitutes	O
for	O
any	O
character	O
or	O
any	O
sequence	O
of	O
random	O
characters	O
in	O
a	O
string	O
.	O
</s>
<s>
Here	O
is	O
an	O
example	O
of	O
wildcard	B-Algorithm
characters	I-Algorithm
in	O
AmigaDOS	B-Operating_System
commands	O
:	O
</s>
<s>
wildcard	B-Algorithm
indicates	O
"	O
any	O
character	O
"	O
.	O
</s>
<s>
AmigaDOS	B-Operating_System
also	O
has	O
the	O
feature	O
of	O
dealing	O
with	O
batch	O
programming	O
,	O
which	O
it	O
calls	O
"	O
script	O
"	O
programming	O
,	O
and	O
has	O
a	O
number	O
of	O
commands	O
such	O
as	O
Echo	O
,	O
If	O
,	O
Then	O
,	O
EndIf	O
,	O
Val	O
,	O
and	O
Skip	O
to	O
deal	O
with	O
structured	O
script	O
programming	O
.	O
</s>
<s>
Scripts	O
are	O
text-based	O
files	O
and	O
can	O
be	O
created	O
with	O
AmigaDOS	B-Operating_System
's	O
internal	O
text	O
editor	O
program	O
,	O
called	O
Ed	B-Application
(	O
unrelated	O
to	O
Unix	B-Application
's	O
Ed	B-Application
)	O
,	O
or	O
with	O
any	O
other	O
third-party	O
text	O
editor	O
.	O
</s>
<s>
To	O
invoke	O
a	O
script	O
program	O
,	O
AmigaDOS	B-Operating_System
uses	O
the	O
command	O
Execute	O
.	O
</s>
<s>
The	O
AmigaDOS	B-Operating_System
command	O
"	O
Run	O
"	O
executes	O
any	O
DOS	O
command	O
or	O
any	O
kind	O
of	O
program	O
and	O
keeps	O
the	O
console	O
free	O
for	O
further	O
input	O
.	O
</s>
<s>
Protection	O
bits	O
are	O
flags	O
that	O
files	O
,	O
links	O
and	O
directories	O
have	O
in	O
the	O
filesystem	B-Application
.	O
</s>
<s>
AmigaDOS	B-Operating_System
supports	O
the	O
following	O
set	O
of	O
protection	O
bits	O
(	O
abbreviated	O
as	O
HSPARWED	O
)	O
:	O
</s>
<s>
If	O
this	O
protection	O
bit	O
is	O
set	O
on	O
,	O
then	O
AmigaDOS	B-Operating_System
is	O
able	O
to	O
recognize	O
and	O
automatically	O
run	O
a	O
script	O
by	O
simply	O
invoking	O
its	O
name	O
.	O
</s>
<s>
In	O
Smart	B-Application
File	I-Application
System	I-Application
(	O
SFS	O
)	O
files	O
and	O
directories	O
with	O
H-bit	O
set	O
are	O
hidden	O
from	O
the	O
system	O
.	O
</s>
<s>
When	O
programming	O
AmigaDOS	B-Operating_System
scripts	O
,	O
one	O
must	O
keep	O
in	O
mind	O
that	O
global	O
variables	O
are	O
system-wide	O
.	O
</s>
<s>
Also	O
,	O
global	O
variables	O
require	O
filesystem	B-Application
access	O
,	O
which	O
typically	O
makes	O
them	O
slower	O
to	O
access	O
than	O
local	O
variables	O
.	O
</s>
<s>
An	O
example	O
demonstrating	O
creative	O
abuse	O
of	O
global	O
variables	O
as	O
well	O
as	O
Lab	O
and	O
Skip	O
is	O
the	O
AmigaDOS	B-Operating_System
variant	O
of	O
the	O
infamous	O
GOTO	B-Application
.	O
</s>
<s>
AmigaDOS	B-Operating_System
is	O
in	O
general	O
case-insensitive	O
.	O
</s>
<s>
Indicating	O
a	O
device	O
as	O
"	O
Dh0	O
:	O
"	O
,	O
"	O
DH0	O
:	O
"	O
or	O
"	O
dh0	O
:	O
"	O
always	O
refers	O
to	O
the	O
same	O
partition	O
;	O
however	O
,	O
for	O
file	O
and	O
directory	O
names	O
,	O
this	O
is	O
filesystem-dependent	O
,	O
and	O
some	O
filesystems	B-Application
allow	O
case	O
sensitivity	O
as	O
a	O
flag	O
upon	O
formatting	O
.	O
</s>
<s>
An	O
example	O
of	O
such	O
a	O
file	B-Application
system	I-Application
is	O
Smart	B-Application
File	I-Application
System	I-Application
.	O
</s>
<s>
This	O
is	O
very	O
convenient	O
when	O
dealing	O
with	O
software	O
ported	O
over	O
from	O
the	O
mostly	O
case-sensitive	O
Un*x	B-Operating_System
world	O
,	O
but	O
causes	O
much	O
confusion	O
for	O
native	O
Amiga	O
applications	O
,	O
which	O
assume	O
case	O
insensitivity	O
.	O
</s>
<s>
Advanced	O
users	O
will	O
hence	O
typically	O
only	O
use	O
the	O
case	O
sensitivity	O
flag	O
for	O
file	B-Application
systems	I-Application
used	O
for	O
software	O
originating	O
from	O
Un*x	B-Operating_System
.	O
</s>
<s>
Re-casing	O
of	O
file	O
,	O
directory	O
and	O
volume	O
names	O
is	O
allowed	O
using	O
ordinary	O
methods	O
;	O
the	O
commands	O
"	O
rename	O
foo	O
Foo	O
"	O
and	O
"	O
relabel	O
Bar	O
:	O
bAr	O
:	O
"	O
are	O
valid	O
and	O
do	O
exactly	O
what	O
is	O
expected	O
,	O
in	O
contrast	O
to	O
for	O
example	O
on	O
Linux	B-Application
,	O
where	O
"	O
mv	O
foo	O
Foo	O
"	O
results	O
in	O
the	O
error	O
message	O
"	O
mv	O
:	O
`foo	O
 '	O
and	O
`Foo	O
 '	O
are	O
the	O
same	O
file	O
"	O
on	O
case-insensitive	O
filesystems	B-Application
like	O
VFAT	B-Application
.	O
</s>
<s>
Users	O
must	O
indicate	O
to	O
the	O
system	O
that	O
"	O
Workbench	O
"	O
is	O
the	O
volume	O
"	O
Workbench	O
:	O
"	O
by	O
always	O
typing	O
the	O
colon	O
"	O
:	O
"	O
when	O
they	O
are	O
entering	O
information	O
in	O
a	O
requester	O
form	O
or	O
into	O
AmigaShell	B-Operating_System
.	O
</s>
<s>
S	O
:	O
for	O
startup	O
scripts	O
,	O
C	B-Language
:	O
for	O
AmigaDOS	B-Operating_System
commands	O
,	O
FONTS	O
:	O
for	O
installed	O
fonts	O
,	O
etc	O
.	O
</s>
<s>
For	O
example	O
,	O
FONTS	O
:	O
might	O
be	O
assigned	O
to	O
SYS:Fonts	O
,	O
then	O
extended	O
to	O
include	O
,	O
for	O
example	O
,	O
Work:UserFonts	O
using	O
the	O
add	O
option	O
of	O
the	O
AmigaDos	B-Operating_System
assign	O
command	O
.	O
</s>
<s>
AmigaDOS	B-Operating_System
supports	O
various	O
filesystems	B-Application
and	O
variants	O
.	O
</s>
<s>
The	O
first	O
filesystem	B-Application
was	O
simply	O
called	O
Amiga	B-Application
FileSystem	I-Application
,	O
and	O
was	O
suitable	O
mainly	O
for	O
floppy	O
disks	O
,	O
because	O
it	O
did	O
not	O
support	O
automatic	O
booting	O
from	O
hard	O
disks	O
(	O
on	O
floppy	O
,	O
booting	O
was	O
done	O
using	O
code	O
from	O
the	O
bootblock	O
)	O
.	O
</s>
<s>
It	O
was	O
soon	O
replaced	O
by	O
FastFileSystem	B-Device
(	O
FFS	O
)	O
,	O
and	O
hence	O
the	O
original	O
filesystem	B-Application
was	O
known	O
by	O
the	O
name	O
of	O
"	O
Old	O
"	O
FileSystem	B-Application
(	O
OFS	O
)	O
.	O
</s>
<s>
With	O
AmigaOS	B-Application
2.x	O
,	O
FFS	O
became	O
an	O
official	O
part	O
of	O
the	O
OS	O
and	O
was	O
soon	O
expanded	O
to	O
recognise	O
cached	O
partitions	O
,	O
international	O
partitions	O
allowing	O
accented	O
characters	O
in	O
file	O
and	O
partition	O
names	O
,	O
and	O
finally	O
(	O
with	O
MorphOS	B-Operating_System
and	O
AmigaOS	B-Application
4	I-Application
)	O
long	O
filenames	O
,	O
up	O
to	O
108	O
characters	O
(	O
from	O
31	O
)	O
.	O
</s>
<s>
Both	O
AmigaOS	O
4.x	O
and	O
MorphOS	B-Operating_System
featured	O
a	O
new	O
version	O
of	O
FFS	O
called	O
FastFileSystem	B-Device
2	O
.	O
</s>
<s>
(	O
However	O
,	O
FF2	O
on	O
AmigaOS	O
4.1	O
differs	O
in	O
that	O
it	O
can	O
expand	O
its	O
features	O
and	O
capabilities	O
with	O
the	O
aid	O
of	O
plug-ins	B-Application
)	O
.	O
</s>
<s>
As	O
with	O
FFS2	O
,	O
the	O
AmigaOS	B-Application
4	I-Application
and	O
MorphOS	B-Operating_System
version	O
of	O
Smart	B-Application
FileSystem	I-Application
is	O
a	O
fork	O
of	O
original	O
SFS	O
and	O
are	O
not	O
100%	O
compatible	O
with	O
it	O
.	O
</s>
<s>
Other	O
filesystems	B-Application
like	O
FAT12	B-Application
,	O
FAT16	B-Application
,	O
FAT32	B-Application
from	O
Windows	O
or	O
ext2	B-Application
from	O
Linux	B-Application
are	O
available	O
through	O
easily	O
installable	O
(	O
drag	O
and	O
drop	O
)	O
system	O
libraries	O
or	O
third	O
party	O
modules	O
such	O
as	O
FAT95	O
(	O
features	O
read/write	O
support	O
)	O
,	O
which	O
can	O
be	O
found	O
on	O
the	O
Aminet	B-Device
software	O
repository	O
.	O
</s>
<s>
MorphOS	B-Operating_System
2	O
has	O
built-in	O
support	O
for	O
FAT	B-Application
filesystems	I-Application
.	O
</s>
<s>
AmigaOS	O
4.1	O
adopted	O
a	O
new	O
filesystem	B-Application
called	O
JXFS	O
capable	O
to	O
support	O
partitions	O
over	O
a	O
terabyte	O
of	O
size	O
.	O
</s>
<s>
Alternate	O
filesystems	B-Application
from	O
third-party	O
manufacturers	O
include	O
Professional	B-Application
FileSystem	I-Application
,	O
which	O
is	O
a	O
filesystem	B-Application
with	O
an	O
easy	O
structure	O
,	O
based	O
on	O
metadata	O
,	O
allowing	O
high	O
internal	O
coherence	O
,	O
capable	O
of	O
defragmenting	O
itself	O
on	O
the	O
fly	O
,	O
and	O
does	O
not	O
require	O
to	O
be	O
unmounted	O
before	O
being	O
mounted	O
again	O
;	O
and	O
Smart	B-Application
FileSystem	I-Application
which	O
is	O
a	O
journaling	B-Application
filesystem	I-Application
which	O
performs	O
journaled	O
activities	O
during	O
system	O
inactivities	O
,	O
and	O
has	O
been	O
chosen	O
by	O
MorphOS	B-Operating_System
as	O
its	O
standard	O
filesystem	B-Application
.	O
</s>
<s>
A	O
DOS7	O
formatted	O
disk	O
cannot	O
be	O
read	O
on	O
original	O
Amiga	B-Device
FFS	I-Device
,	O
and	O
a	O
DOS3	O
disk	O
cannot	O
be	O
read	O
on	O
a	O
KS1.3	O
Amiga	O
.	O
</s>
<s>
However	O
,	O
any	O
disk	O
formatted	O
with	O
DOS0	O
using	O
FFS	O
or	O
FFS2	O
can	O
be	O
read	O
by	O
any	O
version	O
of	O
the	O
Amiga	B-Application
operating	I-Application
system	I-Application
.	O
</s>
<s>
For	O
this	O
reason	O
,	O
DOS0	O
tended	O
to	O
be	O
the	O
format	O
of	O
choice	O
of	O
software	O
developers	O
distributing	O
on	O
floppy	O
,	O
except	O
where	O
a	O
custom	O
filesystem	B-Application
and	O
bootblock	O
was	O
used	O
-	O
a	O
common	O
practice	O
in	O
Amiga	O
games	O
.	O
</s>
<s>
Where	O
software	O
needed	O
AmigaOS	B-Application
2	O
anyway	O
,	O
DOS3	O
was	O
generally	O
used	O
.	O
</s>
<s>
With	O
the	O
July	O
2007	O
Update	O
of	O
AmigaOS	O
4.0	O
in	O
2007	O
,	O
the	O
first	O
two	O
plug-ins	B-Application
for	O
FFS2	O
were	O
released	O
:	O
</s>
<s>
fs_plugin_encrypt	O
:	O
data	O
encryption	O
plug-in	B-Application
for	O
partitions	O
using	O
the	O
Blowfish	B-Algorithm
algorithm	O
.	O
</s>
<s>
AmigaDOS	B-Operating_System
has	O
only	O
a	O
single	O
mandated	O
filename	O
extension	O
:	O
"	O
.info	O
"	O
,	O
which	O
must	O
be	O
appended	O
to	O
the	O
filename	O
of	O
each	O
icon	O
.	O
</s>
<s>
In	O
addition	O
to	O
image	O
data	O
,	O
the	O
icon	O
file	O
also	O
records	O
program	O
metadata	O
such	O
as	O
options	O
and	O
keywords	O
,	O
its	O
own	O
position	O
on	O
the	O
desktop	O
(	O
AmigaOS	B-Application
can	O
"	O
snapshot	O
"	O
icons	O
in	O
places	O
defined	O
by	O
the	O
user	O
)	O
,	O
and	O
other	O
information	O
about	O
the	O
file	O
.	O
</s>
