Paper data storage

Source: Wikipedia, the free encyclopedia.

Paper data storage refers to the use of

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.

Computer memory and Computer data storage types
General
Volatile
RAM
Historical
Non-volatile
ROM
NVRAM
Early-stage NVRAM
Analog recording
Optical
In development
Historical

Though now mostly obsolete, paper was once an important form of

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

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

IBM
.

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

standardized tests
. Banks used magnetic ink on checks, supporting MICR scanning.

In an early electronic computing device, the

dielectric constant
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

Barcodes 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 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

A JAB Code that encodes the text "Wikipedia".

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.[2]

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 8″ × 10″ 600

printing resolution
of about 120,000 dpi in black and white, or 60,000 dpi with CMYK dots.

See also

References

  1. ^ "Herman Hollerith". www.columbia.edu.
  2. ^ Accusoft. "Using Barcodes in Documents – Best Practices". 2007. Retrieved 2014-04-25.


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