An Integrated Library System (ILS) helps to streamline input and retrieval of information through component functions which may include: acquisitions, cataloguing, serials, and the catalogue itself. They can range from simple inventory programs to more complex systems with multiple interconnected components. Even systems where materials never circulate may want a circulation component to track internal use or other requests. Some possible ILS functions are listed below:
Koha was finding use in libraries worldwide, while OPALS and Evergreen also found adoption in the US and Canada. Public libraries sampled in the United States primarily made comitments to adopt Koha, followed by Evergreen. While smaller and medium-sized public libraries were the primary adopters of Koha and Evergreen, the upper bound of the size and complexity of libraries moving to open source ILS products was continuing to increase. In the 2008 environment, almost all libraries implementing open source ILS products did so with paid support contracts.
In addition to volunteer development, open source ILS platforms are developed in part through sponsored development. A library interested in a particular feature, module, or enhancement will pay to have it developed. This improvement can then be cycled back into the next distribution of the ILS so that other libraries can receive the enhancement without cost, benefiting the entire install base.
Journal of Library Administration, 49:401-417, 2009 - Laura Kinner and Christine Rigda, The Univerisy of Toledo
Link to ArticleLibrary system experienced modernization during the 1970s and 1980s. Automated Library Systems (ALSs) often managed by IT staff covered core functionalities including acquisitions, cataloging, circulation, and serials more efficiently than paper systems of the past, but they were not very interactive or user friendly. By the late 1980s, the online public access catalog (OPAC) was the face of the library - a public (though still nongraphical) interfaice for the ALS. The Integrated Library System (ILS) of the 1990s was expanded to integrate other core library modules into the platform functionality.
Beginning with acquisitions and circulation functions, the ILS continued to integrate inventory systems with bibliographic databases, authority control, and serial modules. The ILS was able to be run on mini-computers, rather than needing to be run from mainframe PCs. They were more easily able to be managed by library staff, allowed for MARC record support, and used character-based mode as user interfaces for staff. "By the late 1990s, 'the ILS was functionally complete with good MARC support but with varied network support' (Andrews, 2007, p.573)." WebOpac, the web-based ILS catalog of this time, was built quickly and was not very sophisticated.
The ALS/ILS marketplace was quite dynamic prior to and through the 90s, peaking in the year 1990, but the changes that had been occuring were not sufficient to move libraries into the networked environment of the 2000s. 2005 began a major reshuffling of the industry, with many buyouts and mergers happening around this time. As the market became less saturated, with fewer large companies competing, it was challenged by smaller companies to develop new technologies. The ILS of this era was not a stand-alone product, but a series of add-ons offered across vendors. There was, however, dissatisfaction with some ILS vendors which still had core modules built around old workflows for print materials that did not extend to electronic resources, among other limitations.
While this paper cites a source saying that there are many articles about open source ILS implementations but few case studies that showed success, the following platforms are listed as examples of open source options: Koha, Sakai, Evergreen, and Prospero. As of this article's writing, the open-source movement in libraries had existed for about a decade, and already prompted some library vendors to offer more services.
In no particular order beyond the first 3, some integrated library systems that various Google searches indicated were open source.