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ROS
Address
Read
Address
-
Decode
-
Only
r--.-
Register
Storage
--
Next Address Information
Figure 3-15.
ROS Data Flow
The SAL sense pads are laid out on a
ROS board as in Figure 3-14.
The serial
sense pad connections run vertically on
the card.
Both sides of the ROS board
have identical sense pad patterns, so we
can accommodate 8 ROS documents of 12
words apiece, for a total of 96 ROS
words per ROS board.
The 41< ROS module
is made up of 42 ROS boards for a total
of 4,032 ROS words.
ROS DATA FLOW
The control for the System/360 Model 30
processor is designed around aRCS
device.
It includes hardware for:
1.
Addressing the ROS
2.
Sensing and decoding the output of
ROS
3.
The basic clock
Schematically, it is depicted in
Figure 3-15.
The address register is
decoded to select a word from ROS.
This
word is read out and set into the SALiS.
Some of this information is set into
additional latches, control-register
latches, because it is not used until
the following clock cycle.
The ROS
fields are decoded to activate the
machine control points.
REVIEW QUESTIONS-RCS CONCEPTS
1.
Impulsing a
reads out the
same control gates every time.
2.
An impulsed line driver provides a
pulse through a capacitor to turn on
J
Control
SALS
-
Register
-
Timing Ring
a
L
'----+-
ROS
Field
Decoder
To
Machine
Control
Points
3.
A string of capacitor plates having
a commOn line feeding them is called
a
word
4.
#
line driver (S) may be
impulsed at one time.
5.
The capacitor plates feeding a SAL
are connected
6.
The capacitor plates that are fed
from a line driver are connected in
7.
The RCS word is
bits
wide.
8.
There are
ROS words on
one ROS document.
9.
One ROS board can accommodate
ROS cards.
10.
A 4K module is made up of
ROS boards.
)lICRO PROGRAM)lING INTRCDUCTION
Briefly, to perform the functions of an
Cp code, such as move, add or branch,
requires that the CPU initiate a
sequence of logical steps.
This group
of steps
i~
the System/360 Model 30, is
called a ml.cro program.
Within the
micro program, the ROS word is the func-
tional statement.
An Cp code is read
from main storage by an address initiat-
ed in the ROAR (Read Only Storage
Address Registeq.
When the addressed
ROS word is read, its contents are
decoded to activate control points in
the system.
The ROS word consists of
specific fields selected or programmed
to perform a logic statement.
The acti-
vated word also sends back next address
3-15
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