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DIAGNOSTIC POSITION:
In this position
stopping or ignoring of machine checks
is under the control of a latch that can
be turned on or off with micro-program
words.
RESTART POSITION:
Upon the detection of
an error, action is conditioned
by
the
setting of the Address Compare Switch,
as follows:
1.
With the Address Compare Switch:
In
the SAR Restart, a system reset is
initiated following which the
instruction counter is loaded with
the contents of the Switches F, G,
H, and
J
and an I-cycle is started.
2.
In the ROAR RESTART position or the
ROAR Restart Storage Bypass
position, a recycle reset is given
which resets hardware only (not the
UCW's) and then gates the contents
of Switches F, G, H, and
J
to the
Read Only Storage Address Register
and starts the resulting micro-
program (with or without the of
tion of Main Storage).
3.
In the ROAR Restart Without Reset
position, operation is identical to
that in ROAR Restart position except
that no reset is initiated.
4.
In any other position, operation is
like that in SAR Restart position
except that no reset is initiated.
PROCESS POSITION:
This position is the
position in which problem programs are
processed.
Upon detection of a parity
check with the switch in this position,
the ROS will automatically initiate what
is known as the Malfunction Trap
Routine.
This routine stores the con-
tents of the Check Register in a fixed
location of Main Storage, as well as the
Program Status Word, and upon successful
completion of this task, originates a
Machine Check Interruption.
METER PANEL (FIGURE 6-7)
EM.ERGENCY POWER OFF SWITCH
•
Causes power to turn off beyond the
entry terminal of every unit on the
system.
•
All power in the CPU and all I/O
devices- is dropped immediately.
•
The contents of core storage is not
guaranteed.
o
o
Figure
6-1.
Meter Panel
METERING SWITCH
•
•
•
Enables or disables the timing met-
ers.
Operated by a removable key.
Two positions are:
1.
Normal -- Enable process meter,
disable CE meter.
2.
CE -- Disable process meter,
enable CE meter.
PROCESS METER AND CE METER
•
•
Measure operating time when the CPU
clock is running, the CPU is not in
the Wait state, or no external
interrupts are pending.
The position of the key switch de-
termines which meter is recording
time.
6-17
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