Magazine article American Libraries

A Used-Car Guide to Z39.50

Magazine article American Libraries

A Used-Car Guide to Z39.50

Article excerpt

For all but the most technically adept librarians, attempting to select databases or services for library use that comply with the Z39.50 ANSI standard for information retrieval is a lot like buying a used car in a foreign country. You've bought cars before--but these look a little different, and all of the controls are labeled in a strange language. You know how vulnerable you are to the inevitable hucksters, and you aren't sure you'll be able to explain what you need. And all you want to do is be able to drive!

Even if you don't become fluent in Z39.50, you can learn enough about it to ask a few informed questions. This follow-up to last month's column on the standard won't make you "hucksterproof," but at minimum you will find out surprisingly quickly which vendors can and cannot discuss Z39.50 with you, which will tell you a lot right there.

"Excuse me, do you do Z39.50?"


The Library of Congress, as the official maintenance agency, has developed a list of companies that have registered with the Library of Congress as Z39.50 implementers.

You'll find familiar names such as DRA and SIRSI as well as smaller, more specialized ventures. You may be surprised: In addition to book catalogs, Z39.50 is used for providing access to reference service databases by vendors such as RLG, NLM, and SilverPlatter and is implemented in several technical services products such as BookWhere and ITS for Windows.

"Do you have this in a newer model?"

Asking vendors what version of Z39.50 they support was the most frequent piece of advice I received from vendors and users alike. "Ideally, the answer will be version 3--the latest and greatest," Frank Cervone, assistant director for systems at DePaul University libraries, told me. The Library of Congress page discusses the enhancements to version 3; most of them, such as intermediate result sets, are understandable even to us mere mortals.

As Frank warned, you then have to ask what version of Z39.50 the vendors "do not support or do not fully support.... This is really where all of the problems come in. In many cases, a vendor will claim to support a version, but will not support all of the functionality of the version."

"Do you support the explain feature?"

Be sure to ask vendors if their Z39.50 product complies with a highly desirable feature called explain. Prior to the explain feature, a Z39.50 client had to be configured in advance to be able to speak to each Z39.50 server, which was a cumbersome administrative overhead. With explain, the client queries the server, which then "explains" what kind of server it is and what the client has to do to communicate with it. …

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