<s>
The	O
TU81	B-Device
was	O
a	O
dual-density	O
,	O
9-track	O
,	O
ANSI	O
standard	O
1/2	O
-inch	O
magnetic	O
tape	O
subsystem	O
built	O
and	O
sold	O
by	O
Digital	O
Equipment	O
Corporation	O
.	O
</s>
<s>
The	O
tape	O
drive	O
appeared	O
under	O
TU81	B-Device
,	O
TU81	B-Device
Plus	O
,	O
and	O
TA81	O
model	O
designations	O
.	O
</s>
<s>
The	O
main	O
difference	O
between	O
the	O
TU81	B-Device
and	O
TA81	O
models	O
was	O
the	O
communications	O
interface	O
.	O
</s>
<s>
The	O
TU81	B-Device
Plus	O
included	O
a	O
256Kb	O
cache	O
to	O
improve	O
performance	O
.	O
</s>
