IBM System/7 Functional Characteristics - All about the IBM 1130 ...

1911A1,1Miscellaneous IndicatorsCRY (Carry) LightThis light turns on when the carry indicator for the active interruption level is on.OVRFLW (Overflow) LightThis light turns on when the overflow indicator for the active interruption level is on.SKP (Skip) LightThis light turns on when conditions required for a successful skip by a skip or branchinstruction are satisfied.STP (Stop) LightThis light turns on when the machine stops at the end of its current cycle and enters thestop state under any one of the following conditions:1. The stop key is pressed.2. An error occurs when the check control switch is in the stop-on-error position.3. The rate control switch is in the instruction-step position, or thestop-on-storage-address position, and the conditions applying to that positionare met. (Refer to "Rate Control Switch" later in this chapter.)4. The PSTP (stop) instruction is executed while the console controls are enabled.(See "Console Controls Switch" later in this chapter.)Depressing the reset key on the operator console will also turn on the stop light aswell as the wait light, indicating that the processor is in the manual wait state. (See`Processor States' in Chapter 2, "IBM 5010 Processor Module.")WT (Wait) LightThis light turns on when the machine is in either the wait or manual wait state, whichcan be caused by either of the following:1. A level exit instruction is executed and no interruptions are pending at otherlevels (wait state).2. The system is reset. In this case, the stop light is also turned on (manual waitstate).(See 'Processor States' in Chapter 2, "IBM 5010 Processor Module.")LD (Load) LightThis light turns on when the processor enters the load state to perform an initial programload (IPL) operation. The load light remains on for the duration of the IPL operation,which can result from pressing the program load key or from the auto restart function.The load light also turns on when an initial program load operation is performed froma host system via the 1130 host attachment, the Asynchronous Communications ControlAttachment, or the Binary Synchronous Communications Adapter.TST (Test) LightThis light turns on when the console controls are enabled and either the check controlswitch or the rate control switch is not set to the process position.DATA LightsThese 18 lights consist of 16 data lights and the two associated parity lights (PO and P1).The lights display data at a point in time determined by the setting of the check controland rate control switches. The displayed data is selected by the store/display switches.Operator Console 5-5