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The 8K core array is composed of five
l6,384-core planes (Figure 2-67).
The
first plane forms bit-O and bit-5, the
second plane forms bit-l and bit-6, the
third plane forms bit-2 and bit-7, the
fourth plane forms bit-3 and bit-p, and
half of the fifth plane forms bit-4.
The
top half of the fifth plane is not used in
the 8K array.
Each X-winding travels through five
planes before crossing to the second half
of the core planes via an X-return card at
one end of the array.
This X-return card
contains printed wires that carry X-drive
current from one half of the X-winding to
the other half of the X-winding.
The wind-
ing pattern of the
cor~s
is such that
alternate X-drive lines start at opposite
ends of the core plane (see Figures 2-66
and 2-67 for core positioning).
Printed X-Retum
Wires for Odd-
Numbered Lines
On This End of
X-Return Card.
2 V-Lines
(9ne End
cif
Each)
The Y-drive lines are positioned simi-
larly.
A Y-drive line starts at either the
top or bottom of the first core plane and
is wound through each plane (Figure 2-67).
Thus, if drive current flows through one X-
line and one Y-line, ten cores will experi-
Figure 2-67.
8K Storage Winding
ence the coincident drive current necessary
to affect the cores.
The tenth core, in the
top half of the last plane, experiences
coincident drive 9urrent.
However, this
core output is not sensed.
Depending on the
direction of drive current, the ten cores
are switched to read or switched to write.
An 8K storage unit, such as shown in
Figure 2-67, has eighteen sense/inhibit
windings (two per bit plane).
There are
two windings per bit plane.
Each winding
serves 4,096 cores.
The sense/inhibit
winding is wound parallel to the X-winding.
The 16K core array consists of nine
l6,3,84-core planes.
The first plane forms
bit-O in both first and second 8K units
(Figure 2-68).
The second core plane forms
bit-l in both first and second 8K units.
This same scheme continues through the
ninth core plane which forms bit-P for both
8K units.
An X-winding travels through all
nine planes of one 8K unit before crossing
to the second 8K unit via an X-return card
at the end of the array.
The X-return
card connects the X-winding to the second
8K unit.
The X-winding then continues
through all nine planes of the second 8K
uilit.
The Y-winding goes through both 8K bit-
planes in each of the nine planes.
The
significant point is that the X-winding
experiences a phase reversal when crossing
from one 8K unit to the other.
Because of
this phase reversal, the X- and Y-windings
are in-phase in only one 8K unit at a time.
2-68
Figure 2-68.
16K Storage Winding
Pri nted X -Return
Printed
X-Return
Wire
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