Card image
Encyclopedia
A card image is an archaic term for an ASCII
ASCII
The American Standard Code for Information Interchange is a character-encoding scheme based on the ordering of the English alphabet. ASCII codes represent text in computers, communications equipment, and other devices that use text...

 string
String (computer science)
In formal languages, which are used in mathematical logic and theoretical computer science, a string is a finite sequence of symbols that are chosen from a set or alphabet....

, usually 80 byte
Byte
The byte is a unit of digital information in computing and telecommunications that most commonly consists of eight bits. Historically, a byte was the number of bits used to encode a single character of text in a computer and for this reason it is the basic addressable element in many computer...

s in length. "Card image" refers to a punched card
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...

. IBM cards were 80 characters in length, UNIVAC cards were 90 characters. A single card typically held a single line of text, for example a line of FORTRAN
Fortran
Fortran is a general-purpose, procedural, imperative programming language that is especially suited to numeric computation and scientific computing...

 code. Many data formats, such as the FITS
FITS
Flexible Image Transport System is a digital file format used to store, transmit, and manipulate scientific and other images. FITS is the most commonly used digital file format in astronomy...

 image file format, still use card images as basic building blocks -- even though punched cards are now mostly obsolete.

External links

  • RFC 678: Standard File Formats. The card image format is defined in the section "Standard Formats" of this RFC
    Request for Comments
    In computer network engineering, a Request for Comments is a memorandum published by the Internet Engineering Task Force describing methods, behaviors, research, or innovations applicable to the working of the Internet and Internet-connected systems.Through the Internet Society, engineers and...

    .
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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