Source : Free On-Line Dictionary of Computing

boat anchor
     
        1. Like {doorstop} but more severe; implies that the offending
        hardware is irreversibly dead or useless.  "That was a working
        motherboard once.  One lightning strike later, instant boat
        anchor!"
     
        2. A person who just takes up space.
     
        3. Obsolete but still working hardware, especially when used
        of an old S100-bus hobbyist system; originally a term of
        annoyance, but became more and more affectionate as the
        hardware became more and more obsolete.
     
        [{Jargon File}]