Non-Maskable Interrupt (NMI)

Definition - What does Non-Maskable Interrupt (NMI) mean?

A non-maskable interrupt (NMI) is a type of hardware interrupt (or signal to the processor) that prioritizes a certain thread or process. Unlike other types of interrupts, the non-maskable interrupt cannot be ignored through the use of interrupt masking techniques.

Techopedia explains Non-Maskable Interrupt (NMI)

Common examples of non-maskable interrupt include types of internal system chipset errors, memory corruption problems, parity errors and high-level errors needing immediate attention. In a sense, a non-maskable interrupt is a way to prioritize certain signals within the operating system. Another example is the user event non-maskable interrupt, where a user presses control, alt, delete to create an immediate signal to the system when the computer is not responding. This is a good example because it illustrates a kind of “override” – rather than just following the general thread or process, the ctrl-alt-delete produces a signal that the computer must and will deal with immediately.