Source : Free On-Line Dictionary of Computing

Real Soon Now
     
        (RSN) [Originally from SF's fanzine community, popularised by
        Jerry Pournelle's column in "BYTE"] 1. Supposed to be
        available (or fixed, or cheap, or whatever) real soon now
        according to somebody, but the speaker is quite skeptical.
     
        2. When one's gods, fates, or other time commitments permit
        one to get to it (in other words, don't hold your breath).
     
        [{Jargon File}]