Bar codes

Few retailers, manufacturers or distributors could run a business today without tracking individual items by computer, whether they be groceries at a supermarket checkout, goods on a production line or parcels at a postal sorting office, writes Clive Cookson.

The original – and still the most familiar – tracking device is the machine-readable barcode. Although simple bar codes were introduced in the late 1960s to track rail wagons and factory components, the technology’s breakthrough came in the 1970s when the US supermarket industry decided the time had come to introduce a standardised system for automating checkouts. The initial frontrunner was a “bullseye” system proposed by RCA, in which an 11-digit product code was encoded in concentric rings. But trials showed this to be unreliable and the eventual winner was a linear code developed by IBM, with data encoded in the width and spacing of parallel black and white lines read by a laser scanner.