punched card

punched card: n.obs.  [techspeak] (alt. `punch card') The
   signature medium of computing's {Stone Age}, now obsolescent
   outside of some IBM shops.  The punched card actually predated
   computers considerably, originating in 1801 as a control device for
   mechanical looms.  The version patented by Hollerith and used with
   mechanical tabulating machines in the 1890 U.S. Census was a piece
   of cardboard about 90 mm by 215 mm.  There is a widespread myth
   that it was designed to fit in the currency trays used for that
   era's larger dollar bills, but recent investigations have falsified
   this.

   IBM (which originated as a tabulating-machine manufacturer) married
   the punched card to computers, encoding binary information as
   patterns of small rectangular holes; one character per column,
   80 columns per card.  Other coding schemes, sizes of card, and
   hole shapes were tried at various times.

   The 80-column width of most character terminals is a legacy of the
   IBM punched card; so is the size of the quick-reference cards
   distributed with many varieties of computers even today.  See
   {chad}, {chad box}, {eighty-column mind}, {green card},
   {dusty deck}, {lace card}, {card walloper}.