Magazine article Computers in Libraries

Bar Codes: A Relic of the 20th Century; the Technology Already Exists to Replace Bar Codes with RFID Tags. (the View from the Top Left Corner)

Magazine article Computers in Libraries

Bar Codes: A Relic of the 20th Century; the Technology Already Exists to Replace Bar Codes with RFID Tags. (the View from the Top Left Corner)

Article excerpt

Carol was on the reference desk one day when a fellow called to ask that a book be placed on hold for him. Carol asked him to read the bar code on his library card to her.

"OK," the fellow said. "Thick, thin, thin, thick, thick, thin, thick."

I believe the bar code's days are numbered. I know we just got them on all the items not all that long ago. And then we changed their location to the outside so a self-checkout machine could read them. Originally developed in the 1940s, the bar code is about to become a relic of the 20th century. We'll keep the bar code number for quite a while, but the "thick, thin, thick" of the code itself will be replaced by a Radio Frequency Identification (RFID) tag.

These things are available today. You can buy them from a number of vendors, including 3M, Checkpoint, VTLS, Code-co, Lucatron, and Tech Logic. They are still kind of expensive, but that can't last. At a dollar apiece we're not too interested, but when they get down to a couple of cents it will be cost-effective to switch.

The neat thing about RFIDs is that you can cram a whole lot of stuff into them. This will include the old bar code number for compatibility purposes, but also the title information and the location--on the shelf--specifically. You just walk up to the OPAC (or carry it with you). You ask it where the book is, and the book says, "I'm over here!"

You may laugh, but it's not that far off. When Seattle Public was in the design phase of its fancy new building, one of the concepts brought forward was the idea that the catalog could lead you to the book on the shelf. One of the ideas was colored lights on the floor leading you to the correct location. You could accomplish the same thing with wireless technology. For those folks with earphones always on anyway, it's not that much of a stretch. The technology is here today to do all that. Nothing new needs to be invented.

Why Is Codabar So Popular?

The current standard in libraries is Codabar, a bar code type originally developed for grocery stores, but not, of course, the one they use today. The structure of the library Codabar bar code is well known. A bar code beginning with a "2" denotes a patron number; one with a "3" denotes an item. The next four digits are a unique library identification code. The next eight numbers are the item or patron number, followed by a check digit. This scheme will handle 10,000 separate library systems, each with 100 million items and 100 million patrons.

We have Bela Hatvany to thank for this near-universal scheme. One of the principles of CLSI (Computer Library Services, Inc.) in the very early years, he went on to found SilverPlatter. The CLSI scheme was duplicated by nearly every other library automation vendor that wanted to take business away from CLSI. Naturally, the bar codes had to be compatible. I talked with him at a conference years ago now, and he said, "It's the most enduring thing we ever did!"

How Does Codabar Work?

Bar codes, in all their flavors, are actually a representation of machine language, the zeros and ones that make up bits and bytes. When you read the letter "A" here, you're rending a result, a high-level translation represented as the number 65 in ASCII, the American Standard Code for Information Interchange. That in turn is converted to on/off bits, in this case, 1000001. It's those bits that are manipulated by computer programs such as word processors.

With bar codes, you see the bits in the physical code itself. It's not ASCII, so they don't use the same bits, but it's the same idea. There are four "letters" in the Codabar alphabet: thick bars, thick spaces, thin bars, and thin spaces. A thick bar or space is three bits wide; a thin bar or space is one bit wide.

So, for the gentleman who replied, "Thick, thin, thin, space, thin," he just said the number 5, which looks like this in binary: 11101010001. …

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