Lace card
Encyclopedia
A lace card is a punched card
with all holes punched (also called a whoopee card, ventilator card, flyswatter card, or IBM
doily
). They were mainly used as practical jokes to cause unwanted disruption in card readers
. Card readers tended to jam when a lace card was inserted, as the resulting card had too little structural strength to avoid buckling inside the mechanism. Card punches could also jam trying to produce cards with all holes punched, owing to power-supply problems. When a lace card was fed through the reader, a card knife or card saw (a flat tool used with punched card readers and card punches) was needed to clear the jam.
Another, possibly more significant use of lace cards was to test (or sabotage) computer programs with little or no data validation.
More modern equivalents include the black fax
and computer-based denial of service attacks.
Punched card
A punched card, punch card, IBM card, or Hollerith card is a piece of stiff paper that contains digital information represented by the presence or absence of holes in predefined positions...
with all holes punched (also called a whoopee card, ventilator card, flyswatter card, or IBM
IBM
International Business Machines Corporation or IBM is an American multinational technology and consulting corporation headquartered in Armonk, New York, United States. IBM manufactures and sells computer hardware and software, and it offers infrastructure, hosting and consulting services in areas...
doily
Doily
A doily is an ornamental mat, originally the name of a fabric made by Doiley, a 17th-century London draper. Doily earlier meant "genteel, affordable woolens", evidently from the same source....
). They were mainly used as practical jokes to cause unwanted disruption in card readers
Punched card reader
A punched card reader or just card reader is a computer input device used to read data from punched cards. A card punch is a output device that punches holes in cards under computer control...
. Card readers tended to jam when a lace card was inserted, as the resulting card had too little structural strength to avoid buckling inside the mechanism. Card punches could also jam trying to produce cards with all holes punched, owing to power-supply problems. When a lace card was fed through the reader, a card knife or card saw (a flat tool used with punched card readers and card punches) was needed to clear the jam.
Another, possibly more significant use of lace cards was to test (or sabotage) computer programs with little or no data validation.
More modern equivalents include the black fax
Black fax
The term black fax refers to a prank fax transmission, consisting of one or more pages entirely filled with a uniform black tone. The sender's intention is typically to consume as much of the recipient's fax ink, toner or thermal paper or disk space as possible, thus costing the recipient money...
and computer-based denial of service attacks.