The Jargon File (version 4.4.7, 29 Dec 2003):

interrupts locked out
 adj.

    When someone is ignoring you. In a restaurant, after several fruitless
    attempts to get the waitress's attention, a hacker might well observe “She
    must have interrupts locked out”. The synonym interrupts disabled is also
    common. Variations abound; “to have one's interrupt mask bit set” and “
    interrupts masked out” are also heard. See also spl.