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.

--The Jargon File version 4.3.1, ed. ESR, autonoded by rescdsk.

The 80 characters on regular punched cards are the reason for today's 80 columns in text mode terminals and on most other non-graphical displays. Punch cards usually used a code that was non-binary to store textual information.

Even when the first terminals came around (i.e. IBM 3270), very few installations would want to waste the cpu cycles and memory to run something like editing on their mainframe. (A very large system in the mid-70s would have something like four megabytes of physical memory for about 100 users.)

The punched card is one of the foundations of IT business, used for data storage in those days when a single mainframe computer still filled an entire room. Although... did you know that use of the punch card goes back to the late 1800s when Hermann Hollerith's punch card tabulating equipment was first used in the 1890 US Census? Usually keypunch gear would input data to cards, while machines that sensed the holes with wire brushes read the cards. These brushes made communication with a contact roll, and through an assortment of circuit breakers and relays, could then decipher the holes and the character each hole represented.

The inflexible card with limited storage capacity was replaced slowly but steadily by other data storage systems, although still no less than 37% of all 1996 US Presidential Election voters made use of punch card systems.

Now IBM has developed a new punched card. This one can punch a hole about 6,000 times smaller than the width of a human hair into a piece of plastic. It promises to double the quantity of data that can be stored per square centimetre. The nano-tech punch card could boost the capacity of cell phones, digital cameras and hand-held computers within a few years. The breakthrough was made in Zürich (Switzerland) where it operated under the code name Millipede for the past six years.

The technology, when it is perfected, would theoretically be able to store 25 million pages on a surface the size of a postage stamp, roughly 20 times what can be stored today.

A nanometre is one-millionth of a millimetre in length. Nano-technology storage devices could be available as early as 2005. The technology uses thousands of nanometre-scale tips to punch indentations into a thin plastic film. Unlike the traditional punch cards, the plastic film can be erased and written over again. One advantage of the technology is that it can consume about the same amount of power as the so-called flash memory cards used in many digital devices. Yet it should be able to pack as much as 15 times as much information into the same space and access it at acceptable speeds.