For: DNA barcoding

A bar code (also barcode) is an optical machine-readable representation of data. Originally, bar codes represented data in the widths (lines) and the spacings of parallel lines and may be referred to as linear or 1D (1 dimensional) barcodes or symbologies. But they also come in patterns of squares, dots, hexagons and other geometric patterns within images termed 2D (2 dimensional) matrix codes or symbologies. In spite of their being no bars, 2D systems are generally referred to as barcodes as well.

The first use of barcodes was to automate grocery checkout systems, a task where they have become almost universal today. Their use has spread to many other roles as well, tasks that are generically referred to as Auto ID Data Capture (AIDC). Newer systems, like RFID, are attempting to make inroads in the AIDC market, but the simplicity, universality and low-cost of barcodes has limited the role of these newer systems. It will cost about US$0.005 to implement a barcode compared to passive RFID which still costs about US$0.07 to US$0.30 per tag.

Barcodes can be read by optical scanners called barcode readers or scanned from an image by special software. In Japan, most cell phones have built-in scanning software for 2D codes, and similar software is becoming available on smartphone platforms.

History

In 1932 Wallace Flint started a project at the Harvard University Graduate School of Business Administration to better automate customer purchasing. As punch cards were all the rage at the time, the system they envisioned used a catalog of items with corresponding punch cards for each one. The customer would hand the cards to a clerk who would load them into a reader. The item would then be found and retrieved from a fully automated warehouse.Tony Seideman, "Barcodes Sweep the World", Wonders of Modern Technology An itemized bill was automatically produced. In spite of its promise, punch card systems were expensive and the country was in the midst of the Great Depression. The project never went anywhere, but Flint's efforts would later prove decisive.

Silver and Woodland

In 1948 Bernard Silver, a graduate student at Drexel Institute of Technology in Philadelphia, overheard the president of a local food chain asking one of the deans to research a system to automatically read product information during checkout. Silver told his friend Norman Joseph Woodland about the request, and the two started working on a variety of systems. Their first working system used ultraviolet ink, but this proved to fade and was fairly expensive.

Convinced that the system was workable with further development, Woodland quit his position at Drexel, moved into his father's apartment in Florida, and continued working on the system. His next inspiration came from Morse code, and he formed his first barcode when "I just extended the dots and dashes downwards and made narrow lines and wide lines out of them." To read them, he adapted technology from optical soundtracks in movies, using a 500 watt light bulb shining through the paper onto an RCA935 photomultiplier tube (from a movie projector) on the far side. He later decided that the system would work better if it were printed as a circle instead of a line, which would allow it to be scanned in any direction.