Jacquard Loom card (1801 – 1990s)

The Jacquard Loom was a mechanical loom for cloth weaving, first demonstrated by Joseph Marie Jacquard in 1801. It used a chain of punched cards laced together to allow the loom to create complex patterns.

Any number of the cards could be chained together into a continuous sequence, with each card corresponding to one row of the design. Each position on the card corresponds to a ‘Bolus’ hook which can either be raised or stopped dependent on whether the hole is punched out of the position on the card or not. The hook raises or lowers the harness, which carries and guides the warp thread so that the weft will either lie above or below it.

Modern Jacquard looms are controlled by computers in place of the original punched cards, and can have thousands of hooks.

Charles Babbage was aware of Jacquard loom cards, and planned to use cards to store programs in his Analytical engine, first described in 1837. Later in the 19th Century, Herman Hollerith used the idea of storing information on cards to create the punched card tabulating machine which he used to input data for the 1890 US Census.

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Magic lantern (17th century – 1940s)

The magic lantern was an early type of image projector, developed in the 17th century.

It used a concave mirror behind a light source to direct as much of the light as possible through a small rectangular sheet of glass – the magic lantern slide – on which was the painted or photographic image to be projected – and onward into a lens at the front. The lens was adjusted to focus at the distance of the projection screen or wall.

Initially, candles or oil lamps were used, producing very dim projections. Improvements in lighting took the form of the Argand lamp from the 1790s, limelight in the 1820s, electric arc light in the 1860s and finally the incandescent electric lamp.

The magic lantern could project moving images by the use of various types of mechanical slide, which could be over a foot long at times and could contain gears cranks and pulleys. Even in still slides there was little standardisation. Peck and Snyder, a company with great influence in the magic lantern industry, sold slides measuring 4.5 by 7 inches. ‘English pattern’ slides were 3.5 by 3.5 inches, ‘French pattern slides’ were 3.25 by 4 inches, and the ‘standard European size’ was 3.25 by 3.25 inches.

The art of projection reached a high-point in the 1870-1880 period, and the magic lantern played a very important part in Victorian society. Temperance and religious lectures were given but the lantern was also used in education, for the demonstration of scientific principles, to relay the latest news of world events, and to create ‘phantasmagoria’ shows. By this time, images were being transferred to slides by photographic means, and then coloured by hand. Lanterns of this time could have up to four projection tubes.

With the advent of cinema the days of the big lantern shows were numbered, but magic lanterns were still used in schools and institutes, and photographic and printed slides were still being manufactured in the 1940s.

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Punched tape (1846 – 1980s)

Punched tape or perforated tape was an early form of data storage, developed from interlinked cards such as those used on the Jacquard loom.

In 1846, punched tape was used for sending telegrams. Operators could type a message to the paper tape, and then sent the message at the maximum line speed from the tape.

Various encoding schemes were used over time, beginning with Baudot with 5 holes, and culminating in ASCII. A row of narrower holes served to feed the tape.

When the first minicomputers were being released, manufacturers turned to the existing mass-produced ASCII teleprinters and punched tape became a popular medium for low cost minicomputer data and program storage. Punched tape and punched cards became the primary means of mass storage for computers in the 1960s.

In the 1970s, computer-aided manufacturing equipment often used paper tape, as paper tape readers were smaller and much less expensive than punched card or magnetic tape readers. Premium black waxed and lubricated long-fibre papers, and Mylar film tape were invented so that production tapes for these machines would last longer.

Punched tape had a low information density and took a long time to load, and more than a few dozen kilobytes are impractical to handle in punched tape format. Unlike magnetic tape though, punched tape can be read decades later if acid-free paper or Mylar film was used, and can even be decoded visually if necessary.

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