Paper tape
The paper tape and the Perforated card were the first supports of input-output and the first mass memories used in the beginnings of the Informatique.
Description and operation
The paper tape is a long flexible and solid paper ribbon, bored circular holes laid out in the direction of the width. These holes, laid out in a standardized way, allow encoder values on 8 bits. There exist also punched tapes with 5 holes intended for the Télex.
A hole additional, moreover small size and located about the middle of the band, was used for the drive by the reader-punch.
The paper tape had two advantages on the perforated card: it was much less bulky, and was not likely to be put in disorder. On the other hand, it had a major disadvantage: the modification of a value on the tape implied one to cross to stick (literally), weakening the ribbon.
For example, to modify some Byte S, it was necessary to perforate the new bytes on an end of new ribbon, to cut the part which one wished to remove of the original ribbon, and to insert, by joining, the new end of ribbon. This technique is same as that of the Montage Cinéma tographic. When the desired modification was minor, one could sometimes draw some by perforating (with the hand) an additional hole (transforming one 0 into 1), or by stopping a hole with a sticker.
As the characters were not printed in light, the knowledge of the coding of the characters was necessary for the modification of the ribbon.
These constraints held it for small applications.
Applications
The technology of the paper tapes survived some time, by its use as band guides (or pilot bandages) some Imprimante S. These ribbons were out of plastic, much more robust than the paper of the traditional ribbons. The carriage control tape had several " canaux" and one could, by program, to cause a jump in vertical tabulation, function of the channel (optimized impression of printed forms).
Another application was the hot Line. These means of communication between the great powers at the time of the Cold war required a sure system of Cryptographie, but without technology transfer. The telephone was in fact a teleprinter, where one made a OR exclusive with a ribbon filled with randomness. A ribbon was used to emit, and an identical ribbon was used for the reception.
Gallery
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