Paper data storage refers to the use of

paper Paper is a thin sheet material produced by mechanically or chemically processing cellulose fibres derived from wood, Textile, rags, poaceae, grasses, Feces#Other uses, herbivore dung, or other vegetable sources in water. Once the water is dra ...

as a

data storage device Data ( , ) are a collection of discrete or continuous values that convey information, describing the quantity, quality, fact, statistics, other basic units of meaning, or simply sequences of symbols that may be further interpreted form ...

. This includes

writing Writing is the act of creating a persistent representation of language. A writing system includes a particular set of symbols called a ''script'', as well as the rules by which they encode a particular spoken language. Every written language ...

, illustrating, and the use of data that can be interpreted by a machine or is the result of the functioning of a machine. A defining feature of paper data storage is the ability of humans to produce it with only simple tools and interpret it visually. Though now mostly obsolete, paper was once an important form of

computer data storage Computer data storage or digital data storage is a technology consisting of computer components and Data storage, recording media that are used to retain digital data. It is a core function and fundamental component of computers. The cent ...

as both paper tape and punch cards were a common staple of working with computers before the 1980s.

History

Before paper was used for storing data, it had been used in several applications for storing instructions to specify a machine's operation. The earliest use of paper to store instructions for a machine was the work of

Basile Bouchon Basile Bouchon () (or Boachon) was a textile worker in the silk center in Lyon who invented a way to control a loom with a perforated paper tape in 1725. The son of an organ (music), organ maker, Bouchon partially automated the tedious setting u ...

who, in 1725, used punched paper rolls to control textile looms. This technology was later developed into the wildly successful

Jacquard loom The Jacquard machine () is a device fitted to a loom that simplifies the process of manufacturing textiles with such complex patterns as brocade, damask and matelassé. The resulting ensemble of the loom and Jacquard machine is then called a Jac ...

. The 19th century saw several other uses of paper for controlling machines. In 1846, telegrams could be prerecorded on

punched tape file:PaperTapes-5and8Hole.jpg, Five- and eight-hole wide punched paper tape file:Harwell-dekatron-witch-10.jpg, Paper tape reader on the Harwell computer with a small piece of five-hole tape connected in a circle – creating a physical program ...

and rapidly transmitted using Alexander Bain's automatic telegraph. Several inventors took the concept of a mechanical organ and used paper to represent the music.

Binary punched card

In the late 1880s

Herman Hollerith Herman Hollerith (February 29, 1860 – November 17, 1929) was a German-American statistician, inventor, and businessman who developed an electromechanical tabulating machine for punched cards to assist in summarizing information and, later, in ...

invented the recording of data on a medium that could then be read by a machine. Prior uses of machine readable media, above, had been for control (

automaton An automaton (; : automata or automatons) is a relatively self-operating machine, or control mechanism designed to automatically follow a sequence of operations, or respond to predetermined instructions. Some automata, such as bellstrikers i ...

piano roll A piano roll is a music storage medium used to operate a player piano, piano player or reproducing piano. Piano rolls, like other music rolls, are continuous rolls of paper with holes punched into them. These perforations represent note contro ...

s, looms, ...), not data. "After some initial trials with paper tape, he settled on

punched card A punched card (also punch card or punched-card) is a stiff paper-based medium used to store digital information via the presence or absence of holes in predefined positions. Developed over the 18th to 20th centuries, punched cards were widel ...

s..." Hollerith's method was used in the 1890 census. Hollerith's company eventually became the core of

IBM International Business Machines Corporation (using the trademark IBM), nicknamed Big Blue, is an American Multinational corporation, multinational technology company headquartered in Armonk, New York, and present in over 175 countries. It is ...

. Other technologies were also developed that allowed machines to work with marks on paper instead of punched holes. This technology was widely used for tabulating votes and grading

standardized tests A standardized test is a Test (assessment), test that is administered and scored in a consistent or standard manner. Standardized tests are designed in such a way that the questions and interpretations are consistent and are administered and scored ...

. Banks used magnetic ink on checks, supporting MICR scanning. In an early electronic computing device, the Atanasoff–Berry Computer, electric sparks were used to single small holes in paper cards to represent binary data. The altered

dielectric constant The relative permittivity (in older texts, dielectric constant) is the permittivity of a material expressed as a ratio with the electric permittivity of a vacuum. A dielectric is an insulating material, and the dielectric constant of an insul ...

of the paper at the location of the holes could then be used to read the binary data back into the machine by means of electric sparks of lower voltage than the sparks used to create the holes. This form of paper data storage was never made reliable and was not used in any subsequent machine.

Modern techniques

1D barcodes

Barcode A barcode or bar code is a method of representing data in a visual, Machine-readable data, machine-readable form. Initially, barcodes represented data by varying the widths, spacings and sizes of parallel lines. These barcodes, now commonly ref ...

s make it possible for any object that was to be sold or transported to have some computer readable information securely attached to it.

Universal Product Code The Universal Product Code (UPC or UPC code) is a barcode#Symbologies, barcode symbology that is used worldwide for tracking trade items in stores. The chosen symbology has bars (or spaces) of exactly 1, 2, 3, or 4 units wide each; each decimal ...

barcodes, first used in 1974, are ubiquitous today. Some people recommend a width of at least 3 pixels for each minimum-width gap and each minimum-width bar for 1D barcodes. The density is about 50 bits per linear inch (about 2 bit/mm).

2D barcodes

2D barcodes allow to store much more data on paper, up to 2.9 kbyte per barcode. It is recommended to have a width of at least 4 pixels—e.g., a 4 × 4 pixel = 16 pixel module.

Limits

The limits of data storage depend on the technology to write and read such data. The theoretical limits assume a scanner that can perfectly reproduce the printed image at its printing resolution, and a program which can accurately interpret such an image. For example, an 600 dpi black-and-white image contains 3.43 MiB of data, as does a 300 dpi CMYK printed image. A 2,400 ppi True color (24-bit) image contains about 1.29 GiB of information; printing an image maintaining this data would require a printing resolution of about 120,000 dpi in black and white, or 60,000 dpi with CMYK dots.

References