The other day, I was sitting at the computer and happened to look around, and I spotted a magazine sitting nearby. In one corner, there was the familiar pattern of thin and thick black lines on a white background: The Universal Product Code, or UPC. They are something that is just part of the background, to the point where we normally don't even notice them. There was another one on my can of Coke Zero. There was yet another one on the hint book for one of my computer games. I started to look around more carefully and found that they were everywhere, like grains of sand on a beach: On videotapes and DVDs, on CDs and computer game boxes, on bags of chips and candy bars. Indeed, it was almost impossible to find something that didn't have a UPC on it when purchased. Only some of my very oldest books didn't have a UPC on them.
These days, you'll find one somewhere on the packaging of just about anything you buy. Wikipedia has an article which will tell you everything you ever wanted to know about the UPC barcode system, and maybe more than that. How long have they been in use? Since 1974. Which means that if you want to find something that doesn't have one of those ubiquitous barcodes on it, you'll have to look for something more than a third of a century old.
