:NMI: /N-M-I/ /n./ Non-Maskable Interrupt. An IRQ 7 on the
PDP-11 or 680[01234]0; the NMI line on an 80[1234]86. 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.