NMI

NMI /N-M-I/ n.

Non-Maskable Interrupt. An IRQ 7 on the PDP-11 or 680[01234]0; the NMI line on an 80123486. In contrast with a priority interrupt (which might be ignored, although that is unlikely), an NMI is never ignored. Except, that is, on clone boxes, where NMI is often ignored on the motherboard because flaky hardware can generate many spurious ones.

--The Jargon File version 4.3.1, ed. ESR, autonoded by rescdsk.

No Middle Initial

Many bureaucracies are unable to comfortably deal with deviant behavior such as having no middle name and thus no middle initial. In situations where it is required that some information be present between the first and last names the abbreviation NMI is often used.