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SAL
1
R In
SAL
2
ROut
SAL
3
Gin
Figure 3-11.
Functional Selection
SAL
4
GOut
In our actual CPU, the data flow is a
bit more complex than the one we
developed.
It follows then, that our
choice of control point selection must
be a little more sophisticated.
Our
first consideration will be given to the
physical layout and size of the ROS
word.
The primary unit of capacitor read
only storage is the ROS word.
In the
System/360 Model 30, the ROS word is 60
bits wide.
This means there are 60
capacitor plates on one line driver.
SAL
5
S
In
SAL
6
S Out
SAL
7
Logic
In
SAL
8
Logic
Out
The words are packed on a sheet of Mylar
exactly the same size as an SO-column
punched card.
The plates are positioned
so as to coincide with the normal punch-
ing positions of a card.
They are con-
nected to a line running from the
column-1 end to the column-SO end.
This
allows us to place 12 words on a ROS
document (see Figure 3-13).
This also
gives us the capability of programming
our wordS on existing punched-card
equipment, such as the IBM 24, 514, or
1402.
3-11
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