The Power Panel to the left of the operator's desk is as shown in the schematic below:
The functions are:
POWER ON: this turns the operator's console on. It also recovers the display console buffer storage (containing format
control data) from the values it had on the previous power off
POWER OFF: this turns the operator's console off and saves the contents of the display contents buffer store
EMERGENCY PULL: this turns the whole 360/195 off in an emergency. Once pulled, the only way to reset it it is to get the IBM
customer enginner to reset it.
Operator Control Panel
The Operator Control Panel to the left of the operator's desk is relatively straightforward as shown in the schematic below:
The main functions only work when the EMERGENCY PULL is in its normal position:
POWER ON: the POWER ON button in the Operator Control Panel starts the power on procedure for the complete 360/195.
In the process, the system is reset so no instructions or I/O operations are in process. The POWER ON button is light-up with a white light
and stays that way until the system is powered off or there is a 360/195 malfunction in which case the light turns red.
POWER OFF: initiates the POWER OFF sequence
LOAD: the LOAD key causes the Initial Program Loading (IPL) sequence to be executed from the device set in the LOAD UNIT
LOAD UNIT: The three dials are rotated to define the bottom 11 bits of the device address in hexadecimal. Setting, say,
3A2 would represent the address 011 1010 0010
INTERRUPT: pressing the interrupt key causes an external interrupt to the system as a whole
SYSTEM, MANUAL, WAIT: between them these lights give the state of the system.
The SYSTEM light shows the system is running, the WAIT light says it is in a WAIT state and MANUAL indicates the CPU is in a stopped state. Between them, they give the operator a view of what state the 360/195 is in
TEST: light indicates the system is under manual control such as when the engineer is working on the system
LOAD: the LOAD light indicates the system is on the process of Initial Program Loading (IPL)
Under normal operation, the 360/195 is running under the control of a supervisor program. Interaction with the supervisor program is via the Operator's VDU console.
