Non-maskable interrupt

When a hardware interrupt, the interrupt is specifically triggered by a hardware module or a peripheral device. A distinction is made between maskable ( lockable ) and non- maskable interrupts. Solves a device an NMI ( non- maskable interrupt ), so the NMI port of the processor an active signal is supplied. The processor executes the currently exercised command and leads directly afterwards by an interrupt. On a PC, an NMI is triggered when a hardware reset is to be performed or a fatal hardware error, for example, the "Parity Error". This is a bug in memory, but which can be triggered in case of infestation with the boot virus " Parity Boot ".

In contrast, the interrupt requests (IRQ ) can be masked. These interrupts are on the INTR connector of the processor. For the operation of hardware interrupt, the interrupt controller plays a major role. He manages several interrupt requests and passes them in order of priority to the processor.

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