<s>
The	O
IBM	B-Device
7330	I-Device
Magnetic	O
Tape	O
Unit	O
was	O
IBM	O
's	O
low-cost	O
tape	O
mass	O
storage	O
system	O
through	O
the	O
1960s	O
.	O
</s>
<s>
Part	O
of	O
the	O
IBM	B-Device
7	I-Device
track	I-Device
family	O
of	O
tape	O
units	O
,	O
it	O
was	O
used	O
mostly	O
on	O
1400	B-Device
series	O
computers	O
and	O
the	O
IBM	O
7040/7044	O
.	O
</s>
<s>
The	O
tape	O
had	O
seven	B-Device
parallel	I-Device
tracks	I-Device
,	O
six	O
for	O
data	O
and	O
one	O
for	O
parity	B-Error_Name
.	O
</s>
<s>
Tapes	O
with	O
character	O
data	O
(	O
BCD	O
)	O
were	O
recorded	O
in	O
even	B-Error_Name
parity	I-Error_Name
.	O
</s>
<s>
Binary	O
tapes	O
used	O
odd	B-Error_Name
parity	I-Error_Name
.	O
</s>
<s>
Write	B-Device
protection	I-Device
was	O
provided	O
by	O
a	O
removable	O
plastic	O
ring	O
in	O
the	O
back	O
of	O
the	O
tape	O
reel	O
.	O
</s>
<s>
At	O
200	O
characters	O
per	O
inch	O
,	O
a	O
single	O
2400-foot	O
tape	O
could	O
store	O
the	O
equivalent	O
of	O
some	O
50,000	O
punched	B-Architecture
cards	I-Architecture
(	O
about	O
4,000,000	O
six-bit	O
bytes	O
)	O
.	O
</s>
