Academic journal article Information Technology and Libraries

Z39.50 and LIAS: Penn State's Experience

Academic journal article Information Technology and Libraries

Z39.50 and LIAS: Penn State's Experience

Article excerpt

Pennsylvania State University's experience in developing and implementing Z39.50 into LIAS is explored in this article. The emphasis is on development and implementation issues from the client's point of view, including mapping commands into attributes, cases not covered by Z39.50, processing diagnostics, and connecting to multiple servers. The article wraps up by discussing Penn State's current and anticipated applications for Z39.50.


LIAS (Library Information Access System) has been developed in-house at Penn State since the mid-1970s. It has served as the cataloging facility for the Penn State Libraries since January 1981, and the LIAS online catalog has been available to the public since 1983. LIAS supports all activities associated with cataloging: preorder searching, record input and editing, importing records into LIAS from USMARC or OCLC, online shelflisting, and creation of spine and book labels. LIAS also supports a circulation-control system, the fund-accounting component of acquisitions processing, and management statistics programs. In 1992, LIAS began to offer access to journal article databases such as Uncover and ERIC. Uncover, which indexes more than 10,000 scholarly and popular journals, resides on a mainframe in Colorado; LIAS provides transparent telecommunications access to this service. ERIC, which is produced by the U.S. Department of Education, provides access to more than 750 journals and a vast education collection on microfiche. ERIC is locally mounted in LIAS and searchable with the same commands used in the LIAS online catalog. Currently, a fully automated acquisitions component is under development and is anticipated to be operational in late 1993.

Penn State's LIAS runs on a DEC VAX 10,000 with one gigabyte main memory and seventy gigabytes of disk storage. At the present time it supports more than 600 PCs, Macintosh computers, and dumb terminals.

LIAS serves the entire Penn State Libraries system, including the central campus at University Park, as well as more than twenty branch campuses throughout Pennsylvania. A typical week's activity is about one million transactions.


In 1989, Penn State and the University of California received grants from Digital Equipment Corporation (DEC) to support linking the library systems at these institutions via the Z39.50 protocol. Figure I outlines the history of this development effort. The initial effort at Penn State focused on building a server to handle incoming requests from the University of California and integrating a Z39.50 client into LIAS to search the UC database. At this time, Z39.50 was evolving from version 1 to version 2, which complicated the development environment. We were committed to supporting version 2, although it was not yet fully fleshed out. Eventually, the scope of Penn State's project was expanded to other information systems, including a number of abstracting and indexing databases as well as the library Utilities OCLC and RLG. At Penn State the analysis was a shared effort by our two senior development staff, along with a full-time analyst-programmer, who also wrote the client-server code.


Simply stated, the client (or "origin," in Z39.50 terminology) is the system that sends a search request to another system (the server) that contains the database being searched. Basically, the client translates a user's local command into the Z39.50 standard, encodes this information into a Z39.50 APDU (application protocol data unit) using the ASN.1 Basic Encoding Rules, and ships it to the server. The means of transmission that PSU uses is TCP/IP; however, this is not a requirement of the standard. The abbreviation "ASN.1" stands for "abstract syntax notation one" and lays out the basic ground rules on how to represent data. The server, in turn, decodes the ASN. …

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