Computers are widespread, with a great many things being computerized, including things that we don't normally think of as being computerized. These computers, large and small, doing jobs tiny and massive, run on varying complexities of codes. One such code is QR Code. Given the lack of imagination of the folks who name computer codes, it is perhaps no surprise that the term stands for nothing more interesting than Quick Response Code. Such code can be found today running thousands of different things, from cars to camera phones.
Despite its many uses, QR Code is a plain old matrix code. It is confined to two dimensions, so you can't see a real picture of it. QR Code was manufactured with the intent of decoding it at very high speeds, so the third dimension wasn't deemed necessary. It is also a relatively new code, having been created in 1994, in Japan. That country, by the way, still sees its most prevalent use, although much of what it powers is exported to the rest of the world.
QR Code was created as a step up from a bar code. It contains data in both vertical and horizontal directions, whereas a bar code has only one direction of data, usually the vertical one. The code can also correspondingly hold more information. It is easily digested by scanning equipment, and because it has potentially twice the amount of data as bar code, it can increase the effectiveness of such scanning.
Further analysis shows that QR Code can handle alphanumeric character, symbol, binary, and other kinds of code. It can hold up to 7,089 characters in a single symbol. That is numeric only, of course. The limit on alphanumeric characters in one QR Code symbol is a respectable 4,296. In addition to being denser than binary code, it is also much smaller, showing Moore's Law at work. QR Code also has an error-correction capability, whereby the data can be brought back to full life even if the symbol has been trashed. All of these features make it far superior to bar code.
Camera phone manufacturers in Japan have begun including QR Code-reading software in their products, making it much easier for users to store and retrieve data—and more of it. This code has migrated to other, nontraditional media as well, including business cards and magazines.