Source : Free On-Line Dictionary of Computing

scrool
     
        /skrool/ [The pioneering Roundtable chat system in Houston
        ca. 1984; probably originated as a typo for "scroll"] The log
        of old messages, available for later perusal or to help one
        get back in synch with the conversation.  It was originally
        called the "scrool monster", because an early version of the
        roundtable software had a bug where it would dump all 8K of
        scrool on a user's terminal.
     
        [{Jargon File}]