<s>
Digital	B-Architecture
Data	I-Architecture
Storage	I-Architecture
(	O
DDS	O
)	O
is	O
a	O
computer	O
data	O
storage	O
technology	O
that	O
is	O
based	O
upon	O
the	O
Digital	O
Audio	O
Tape	O
(	O
DAT	O
)	O
format	O
that	O
was	O
developed	O
during	O
the	O
1980s	O
.	O
</s>
<s>
DDS	O
is	O
primarily	O
intended	O
for	O
use	O
as	O
off-line	O
storage	O
,	O
especially	O
for	O
generating	O
backup	B-Protocol
copies	I-Protocol
of	O
working	O
data	O
.	O
</s>
<s>
Notice	O
in	O
HP	O
's	O
article	O
that	O
newer	O
tape	O
standards	O
do	O
not	O
simply	O
consist	O
of	O
longer	O
tapes	O
;	O
with	O
DDS-2	B-Architecture
,	O
for	O
example	O
,	O
the	O
track	O
was	O
narrower	O
than	O
with	O
DDS-1	B-Architecture
.	O
</s>
<s>
At	O
one	O
time	O
,	O
DDS	O
competed	O
against	O
the	O
Linear	B-Operating_System
Tape-Open	I-Operating_System
(	O
LTO	O
)	O
,	O
Advanced	B-Device
Intelligent	I-Device
Tape	I-Device
(	O
AIT	O
)	O
,	O
VXA	B-Device
,	O
and	O
Travan	B-Device
formats	O
.	O
</s>
<s>
However	O
,	O
AIT	O
,	O
Travan	B-Device
and	O
VXA	B-Device
are	O
no	O
longer	O
mainstream	O
,	O
and	O
the	O
capacity	O
of	O
LTO	O
has	O
far	O
exceeded	O
that	O
of	O
the	O
most	O
recent	O
DDS	O
standard	O
,	O
DDS-320	O
.	O
</s>
<s>
DDS-1	B-Architecture
Stores	O
up	O
to	O
1.3	O
GB	O
uncompressed	B-General_Concept
(	O
2.6	O
GB	O
compressed	B-General_Concept
)	O
on	O
a	O
60	O
m	O
cartridge	O
or	O
2	O
GB	O
uncompressed	B-General_Concept
(	O
4	O
GB	O
compressed	B-General_Concept
)	O
on	O
a	O
90	O
m	O
cartridge	O
.	O
</s>
<s>
The	O
DDS-1	B-Architecture
cartridge	O
often	O
does	O
not	O
have	O
the	O
-1	O
designation	O
,	O
as	O
initially	O
it	O
was	O
the	O
only	O
format	O
,	O
though	O
cartridges	O
produced	O
since	O
the	O
introduction	O
of	O
DDS-2	B-Architecture
may	O
carry	O
a	O
-1	O
designation	O
to	O
distinguish	O
the	O
format	O
from	O
newer	O
formats	O
.	O
</s>
<s>
A	O
media	O
recognition	O
system	O
was	O
introduced	O
with	O
DDS-2	B-Architecture
drives	O
and	O
cartridges	O
to	O
detect	O
the	O
medium	O
type	O
and	O
prevent	O
the	O
loading	O
of	O
an	O
improper	O
medium	O
.	O
</s>
<s>
From	O
1993	O
,	O
DDS-1	B-Architecture
tapes	O
included	O
the	O
media	O
recognition	O
system	O
marks	O
on	O
the	O
leader	O
tapea	O
feature	O
indicated	O
by	O
the	O
presence	O
of	O
four	O
vertical	O
bars	O
after	O
the	O
DDS	O
logo	O
.	O
</s>
<s>
DDS-2	B-Architecture
Stores	O
up	O
to	O
4	O
GB	O
uncompressed	B-General_Concept
(	O
8	O
GB	O
compressed	B-General_Concept
)	O
on	O
a	O
120	O
m	O
cartridge	O
.	O
</s>
<s>
DDS-3	B-Architecture
Stores	O
up	O
to	O
12	O
GB	O
uncompressed	B-General_Concept
(	O
24	O
GB	O
compressed	B-General_Concept
)	O
on	O
a	O
125	O
m	O
cartridge	O
.	O
</s>
<s>
DDS-3	B-Architecture
uses	O
PRML	B-Device
(	O
Partial	B-Device
Response	I-Device
Maximum	I-Device
Likelihood	I-Device
)	O
to	O
minimize	O
electronic	O
noise	O
for	O
a	O
cleaner	O
data	O
recording	O
.	O
</s>
<s>
DDS-4	B-Architecture
DDS-4	B-Architecture
stores	O
up	O
to	O
20	O
GB	O
uncompressed	B-General_Concept
(	O
40	O
GB	O
compressed	B-General_Concept
)	O
on	O
a	O
150	O
m	O
cartridge	O
.	O
</s>
<s>
DAT	B-Architecture
72	I-Architecture
DAT	B-Architecture
72	I-Architecture
stores	O
up	O
to	O
36	O
GB	O
uncompressed	B-General_Concept
(	O
72	O
GB	O
compressed	B-General_Concept
)	O
on	O
a	O
170	O
m	O
cartridge	O
.	O
</s>
<s>
The	O
DAT	B-Architecture
72	I-Architecture
standard	O
was	O
developed	O
by	O
HP	O
and	O
Certance	O
.	O
</s>
<s>
It	O
has	O
the	O
same	O
form-factor	O
as	O
DDS-3	B-Architecture
and	O
-4	O
and	O
is	O
sometimes	O
referred	O
to	O
as	O
DDS-5	O
.	O
</s>
<s>
DAT	O
160	O
DAT	O
160	O
was	O
launched	O
in	O
June	O
2007	O
by	O
HP	O
,	O
stores	O
up	O
to	O
80	O
GB	O
uncompressed	B-General_Concept
(	O
160	O
GB	O
compressed	B-General_Concept
)	O
.	O
</s>
<s>
Despite	O
the	O
difference	O
in	O
tape	O
widths	O
,	O
DAT	O
160	O
drives	O
can	O
load	O
DAT-72	O
and	O
DAT-40	O
(	O
DDS-4	B-Architecture
)	O
cartridges	O
.	O
</s>
<s>
Launch	O
interfaces	O
were	O
Parallel	O
SCSI	O
and	O
USB	B-Protocol
,	O
with	O
SAS	O
interface	O
released	O
later	O
.	O
</s>
<s>
DAT	O
320	O
In	O
November	O
2009	O
HP	O
announced	O
the	O
DAT-320	O
standard	O
,	O
which	O
stores	O
up	O
to	O
160	O
GB	O
uncompressed	B-General_Concept
(	O
marketed	O
as	O
320	O
GB	O
assuming	O
2:1	O
compression	O
)	O
per	O
cartridge	O
.	O
</s>
