Paper tapes

paper tapes served plastic volumes from center of the nineteenth century in the twentieth century of the representation and storage of data on long paper or also. First they were used in the data communication by Telegrafen. Morse became - points (short signals) z. B. by perpendicularly standing holes,By diagonally arranged holes codes lines (long signals) (Wheatstone - paper tape code). Those today still well-known paper tapes are used as storage medium for teleprinters and computers.

Joseph Marie Jacquard used for the first time 1805 paper tapes as control unit of a weaving loom. The paper tape is the forerunner of the punch card asData memory. The punch card as data memories was inserted for the first time 1890 of the national administration in the USA during the census by Herman Hollerith.

The write/read principle essentially corresponds to the punch cards up to the format of the data medium:

For describing a paper tape stamping machines were used, inright angle for direction of travel a border of punching heads possessed. For everyone (or) indications which can be transmitted which can be stored a column of the paper tape with an appropriate sample was bestanzt. Afterwards the strip was resumed by in the center along the volume of running sprocket holes a positionand the next indication written.

The appropriate reader consisted of a set of contact pins, which corresponded to the punching heads of the writer in their arrangement. The paper tape was put over the pins, which could close only one contact, if at their respective position a hole were punched out.Like the letter also reading took place character by character. Typically write/read speeds of approximately 6 indications/second were reached. (See also teleprinters.) newer readers used light barriers in place of the contact pins and could thereby substantially faster work.

A set of holes with n possible hole positions permits the representation of 2 n different indications. Common codes were the Baudot code with five hole positions for teleprinters and ASCII with seven or eight (sieve plus parity bit) hole positions for computer applications.

5-Bit Lochstreifen (Baudot-Code)
5-Bit paper tape (Baudot code)

paper tape and similar mechanical memory systems as punch cards were before arising magnetic storage media as that Magnetic tape and the magnetic disk the most economical les and recordable data medium. Due to its robustness, the simple handling and it widens spreading as well as the fact that they can be read if necessary with the naked eye, became still paper tapes in small measure at the beginning of the einundzwandzigsten century z. B.used in the military communications technology. Within the computer range they lost their meaning however.

see also

 

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