0
Punch cards are read by a punch card reader which has a matrix of pins that match the layout of the card. Each pin represent a bit (a 1 or a 0). Once the card is loaded, the pins are pressed against the card. If there's a hole, the pin passes through the hole and makes contact with an aperture on the other side, thus creating an electric circuit. This registers as a one (1). Pins that do not make a circuit register as a zero (0). The "value" of the card is then passed to the computer's memory at the current offset which is then incremented by the number of bits stored on each card. The pins are then retracted and the next card is loaded.
Cards are typically laced together using thread to form a continues chain of cards while a stepping motor feeds the cards into the reader one at a time using a sprocket wheel that engages with a series of regular-spaced holes down one side of the card (much like a film reel at the movies).
Wiki User
∙ 8y ago
Wiki User
∙ 13y agoThe cards had binary code.
Add your answer:
Earn +20 pts
What was the term used for the first paper input medium used in early IBM mainframe computers?
punched card, but they developed that card in 1924 for their electromechanical EAM machines, by modifying a punched card developed in 1890 by Herman hollerith.
What was the significance of the punch card?
It is the medium by which people communicate with computers in the olden days. Computer programs are written in punched cards, input data are also written in punched cards. There was a special machine called "card reader" to interpret what were in the punched cards and convert them into machine readable form.
What is electronic punch card system?
An electronic punch card system was the first data entry system for computers. Cards were punched with holes according to the information that was stored or directions for the computer. The card was inserted into a card reader and the data was collected. Factories still use a type of punch card system with their manual time cards. Only with the time card, information is printed on the card instead of holes punched.
10 basic flowcharting?
# Decision # Data(I/O) # Document # Multi-Document # Preparation # Display # Manual Input # Manual Operation # Card # Punched Tape
Punched - card data processing as invented by whom?
Punched- card data processing was invented ny Herman Hollerith.
What is punched card?
A punch card are cards with punched holes in them that represent data. You feed them into a (usually) large-scale computer that can accept them.
Why do you use keyboards?
Because the computer can't read my thoughts and I need some way to tell it what I want it to do. When I first started using computers you used punched cards to do that and the keypunch that punched the cards had a keyboard but was not connected to the computer. You punched the deck using the keyboard on the keypunch, then took the deck to the computer's card reader.
What are punch cards?
Punch cards are a very old way of programming a computer. The punch card would have long rows of numbers, representing certain instructions. You would punch a hole through the number corresponding to the instruction you wanted to execute. You would then feed the card into the computer, and it would run the program.
Where is computer's sound card input?
There are jacks located on the back of the computer. Some newer computers will have the same jacks on the front.
What is addressing mode in memory management?
punched card
Are expansion cards an input or output device?
Input I would have thought.If you are refering to the big readers of the 80-column punched card then they are Input devices. But many of these devices were made so that they could also be used for output - ie for punching cards - these are both Input and Output devices.A card reader is an INPUT (not imput) device.Whenever you are trying to categorize a device as Input or Output, think of how it looks from the computer.If the computer is transmitting data to it, it is an Output device.If the computer is receiving data from it, it is an Input device.
What has the author Wallace John Eckert written?
Wallace John Eckert has written: 'Punched card methods in scientific computation' -- subject(s): Punched card systems, Astronomy, History
