<s>
Rod	B-General_Concept
memory	I-General_Concept
is	O
one	O
of	O
the	O
many	O
variations	O
on	O
magnetic	O
core	O
memory	O
that	O
attempts	O
to	O
lower	O
costs	O
by	O
automating	O
its	O
manufacturing	O
.	O
</s>
<s>
It	O
was	O
introduced	O
by	O
NCR	O
in	O
1964	O
as	O
part	O
of	O
the	O
NCR	B-Device
315	I-Device
RMC	O
computer	O
,	O
RMC	O
for	O
"	O
rod	B-General_Concept
memory	I-General_Concept
computer	O
"	O
.	O
</s>
<s>
It	O
was	O
also	O
used	O
in	O
their	O
Century	B-Device
line	O
.	O
</s>
<s>
Like	O
many	O
similar	O
concepts	O
,	O
notably	O
twistor	B-General_Concept
memory	I-General_Concept
and	O
thin	B-General_Concept
film	I-General_Concept
memory	I-General_Concept
,	O
rod	B-General_Concept
memory	I-General_Concept
was	O
competing	O
for	O
the	O
role	O
of	O
taking	O
over	O
from	O
core	O
when	O
the	O
first	O
semiconductor	B-Architecture
memory	I-Architecture
systems	O
wiped	O
out	O
the	O
entire	O
market	O
in	O
1970	O
.	O
</s>
<s>
Instead	O
of	O
magnetic	O
rings	O
,	O
the	O
cores	O
,	O
rod	B-General_Concept
memory	I-General_Concept
uses	O
magnetic	O
bars	O
surrounded	O
by	O
a	O
metal	O
coil	O
.	O
</s>
<s>
Instead	O
of	O
the	O
electrical	O
current	O
running	O
linearly	O
and	O
the	O
magnetic	O
field	O
around	O
the	O
core	O
,	O
in	O
rod	B-General_Concept
memory	I-General_Concept
the	O
current	O
runs	O
around	O
the	O
solenoid	B-Algorithm
and	O
the	O
magnetic	O
field	O
is	O
linear	O
in	O
the	O
rod	O
.	O
</s>
<s>
To	O
do	O
this	O
,	O
the	O
rods	O
are	O
placed	O
in	O
the	O
middle	O
of	O
tiny	O
solenoids	B-Algorithm
,	O
which	O
produce	O
a	O
linear	O
field	O
in	O
one	O
direction	O
or	O
the	O
other	O
depending	O
on	O
which	O
direction	O
the	O
current	O
is	O
flowing	O
.	O
</s>
<s>
Separately	O
,	O
another	O
machine	O
is	O
fed	O
copper	O
wire	O
and	O
periodically	O
creates	O
small	O
coils	O
of	O
ten	O
windings	O
forming	O
a	O
solenoid	B-Algorithm
.	O
</s>
<s>
The	O
assembly	O
machinery	O
then	O
left	O
a	O
short	O
section	O
of	O
the	O
wire	O
unbent	O
,	O
before	O
winding	O
another	O
solenoid	B-Algorithm
into	O
the	O
wire	O
,	O
and	O
so	O
on	O
.	O
</s>
<s>
A	O
number	O
of	O
these	O
ropes	O
were	O
then	O
laid	O
parallel	O
to	O
each	O
other	O
and	O
a	O
second	O
set	O
of	O
straight	O
wires	O
run	O
parallel	O
to	O
the	O
ropes	O
so	O
they	O
lay	O
under	O
one	O
end	O
of	O
the	O
solenoids	B-Algorithm
.	O
</s>
<s>
The	O
assembly	O
is	O
then	O
completed	O
by	O
inserting	O
one	O
of	O
the	O
rods	O
though	O
a	O
series	O
of	O
the	O
solenoids	B-Algorithm
and	O
the	O
potting	O
the	O
entire	O
assembly	O
.	O
</s>
<s>
The	O
economy	O
of	O
machine	O
assembly	O
was	O
augmented	O
by	O
selling	O
rod	B-General_Concept
memory	I-General_Concept
without	O
paying	O
patent	O
royalties	O
on	O
core	O
memory	O
to	O
NCR	O
's	O
competitor	O
,	O
IBM	O
.	O
</s>
