Perforated card
The perforated card (sometimes called chart Hermann Hollerith ) and the paper tape were the first supports of input-output and the first mass memories used in the beginnings of the Informatique. The perforated card had been used before in Mécanographie.
They appeared before the Operating systems, and allowed the creation of those. However, it took whole hours to write a program of some lines of code.
Appearance and disappearance
It is Basile Bouchon which invented the paper perforated in 1725; in 1728, Jean-Baptiste Falcon improved the system in the form of chart rigid, and they were used for the Jacquard looms in 1801. It were then used for various Automate S, and in particular the barrel organs and the player pianos.
The invention of the machine with perforated cards by Hermann Hollerith, for the Census of 1890 to the the United States, was the base of the development of three international large companies: IBM, Powers (absorptive by Remington-Rand, and amalgamated in Unisys), and Bull. The Hollerith charts measured 6 centimetre out of 12 and comprised 210 boxes.
The model more the current of perforated cards, Patented by IBM in the Years 1930, was the chart known as with 80 columns . It is about a thin Bristol-board sheet of rectangular form, whose corner was truncated, where the characters (EBCDIC or ASCII) were translated by rectangular perforations (1,2 or 3 by character) laid out into columns parallel with the width (80 columns) and on 13 lines parallel with the length. These charts were stored by boxes of 2.000, and the truncated corner was used as reference mark to insert them in the good sense in a card hopper or to give them to the place when the box fell by ground…
The charts were perforated by specialized operators working starting from “forms of seizure”, checked by re-typing by other operators (“punch-card operators”) whose normal rate of seizure was of approximately: 15000 characters per hour (either approximately 4 characters at the second). The charts were likely to be sorted on machines called “sorter-collator”. The calculators used these charts until the replacement of the last of these machines by computers about 1970. The computers were equipped with peripheral units able to read and perforate these charts until the beginning of the Années 1980.
The mechanism of reading of the perforated cards was very particular. Indeed, a needle reviewed the lines and columns of the chart. On the other side of the chart, was a bucket fills of mercury. If the needle touched mercury, an electric current transmitted in the needle passed and completed, which indicated the presence of a hole.
At the beginning of the Years 1960, the first monitors of computer working in “text mode” comprised 80 columns per line in order to be compatible with the perforated cards. In 2006, many computers, AS400 for example, still work with this type of screen, even if it is sometimes masked by a graphic software of preparing functioning on the PC which replaces the dumb terminal.
The programs in languages COBOL, FORTRAN and PL/1 were written on lines of 80 characters to the maximum to be able to be perforated on charts.
The perforated card gradually disappeared during the Années 1970 when the units of input-output with Magnetic band appeared and with flexible Disquette S of format “8 inches” and from the mass memories more powerful.
Other format of perforated cards
Other models of perforated cards were proposed, in particular a chart with 132 columns , with circular holes of reduced size, but they were used little (132 was the number of printable natures per line of the most widespread chain printers).
IBM also marketed charts with 96 columns with round perforations.
See too
There were also charts allowing the direct data entry the source of information on precut charts with confettis, said charts perfostyl or charts perfoguide. The theoretical test of the Driving license in France called upon this process between 1981 and 1996 and the theoretical examination of the Hunting permit still makes use of it in 2007.Related articles
External bonds
- workshop of creation of paperboards perforate
- Computer History Museum: First Dated Storage Mechanism
- Machine Hollerith
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