piggybacking

from The Free On-line Dictionary of Computing (8 July 2008)
piggybacking

   1. A method for passing {acknowledgement frames} and {data
   frames} in the same direction along a line.

   2. The practice of increasing memory capacity by soldering
   chips on top of other chips.  The chip-enable or high address
   pins would be connected to the {address bus} by a flying lead.
   Many {Ohio Superboards} were expanded to a massive 8K of {RAM}
   in this way.

   (1994-11-29)
    

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