Empower your library


What is SFX?

SFX is the original, award-winning context-sensitive link server from Ex Libris™. SFX allows context-sensitive linking between Web resources in the scholarly information environment. OpenURL-compliant, SFX accepts an OpenURL as input from an information resource, which is referred to as an SFX source.

An SFX server facilitates the management of a library's interlinked electronic collection by providing libraries with an independent means of seamlessly interconnecting their ever-increasing collections of heterogeneous resources. Because SFX allows libraries to define the links between information resources, the resources become fully integrated in the overall library service no matter who hosts them- the library itself or external information providers.

The SFX solution offers libraries flexibility and choice. Reference librarians can choose appropriate content from a range of information vendors, interconnect this content as desired, and then provide links to "appropriate" services for their end users. Reference librarians need not depend solely on the linking services defined by the information providers, on a specific set of identifiers (such as ISSN, SICI, or DOI), or on particular communication protocols (such as Z39.50 or HTTP).

What are the key benefits of SFX for my institution?

  1. Linking services are independent of an information resource, so the institutional librarian can define the relevant links.
  2. The librarian configures links only once, and they are available to many information services.
  3. Extended linking beyond just links to full text can be offered to library patrons.
  4. A consistent linking approach across a range of information resources makes it easier for the patron to navigate heterogeneous resources.
  5. Vendor-independent measures of use are available.
  6. Once configured, SFX serves as a valuable repository for e-journal information in the library. SFX can generate alphabetical journal title lists and can optionally provide MARC records for loading into a library catalog.


What is an OpenURL?

An OpenURL is the mechanism that makes open linking in the Web-based scholarly information environment possible. The OpenURL standard provides the syntax for transporting bibliographic metadata and identifiers of objects between information services.

The OpenURL standard was developed by Oren Beit-Arie, of Ex Libris, and Herbert Van de Sompel, who was then at Ghent University in Belgium (he is currently at the Los Alamos National Laboratory).

The OpenURL version 0.1 standard, as submitted to NISO by Beit-Arie and Van de Sompel, is now a widely adopted, de facto standard. OpenURL version 1.0 has been finalized and goes to NISO ballot in early January 2004. OpenURL 1.0 will be known as NISO standard Z39.88(2004) (see http://www.niso.org/committees/committee_ax.html).

To find out more about the OpenURL standard and to access the OpenURL specification, see http://library.caltech.edu/openurl.

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What is the OpenURL framework?

The OpenURL framework is the architecture that describes how to establish open linking across systems. It is about how to provide linking services to objects that are identified or described by metadata. At the core of the framework is the notion of disconnecting the provision of linking services from the information resource itself, thereby allowing a third-party component, under the control of the local library, to determine appropriate linking services. Such a third-party component is known as a link server, of which SFX is an example.

Any information resource can participate in the OpenURL framework by providing OpenURL links that point to the user's preferred link server, which computes and resolves the appropriate, context-sensitive extended links. The OpenURL framework is compatible with and complementary to other linking solutions, such as CrossRef (see www.crossref.org).

SFX sources: An SFX source is a Web-based resource in which a library patron searches and from which the patron can link out to additional resources and services by clicking an SFX button. The SFX button activates an OpenURL that sends metadata to the SFX server. A resource can be an SFX source only if the resource provides an OpenURL. For a list of those vendors who have implemented the OpenURL or committed to do so, see sources.

SFX targets: An SFX target is where a user "lands"- that is, the target of a link from an SFX source. SFX relies on "link-to" or search syntaxes for a target information service. Many such syntaxes exist today and vary quite widely from one information service provider to another- be they publishers or OPAC vendors. For example, one syntax for linking to an electronic journal might include the domain name and a unique journal identifier, whereas others include an abbreviated journal name followed by the journal year and issue number. The "deeper" an SFX link can go, the more effective the SFX link will be. In most cases, the syntax available from the publishers allows direct linking to the journal article level. For a list of predefined SFX targets, see targets.

SFX provides a tool kit to plug in SFX target services of your choice, such as links to local document delivery services and local data repositories.

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Who is using SFX?

SFX is setting the standard for OpenURL link servers. Used by more than 1000 libraries, SFX is the most widely used link server in libraries worldwide.

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Who developed SFX?

The SFX framework- later generalized as the OpenURL Framework- was conceived of and formulated by Herbert Van de Sompel of Ghent University. Dr. Van de Sompel's research is well documented in his D-Lib research papers. You can find links to these papers at our SFX articles section.

The SFX server technology was developed during the research work undertaken by Dr. Van de Sompel and was acquired by Ex Libris in February 2000. After a successful beta test with five U.S. institutions during 2000, SFX was released to the market in February 2001.

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Does SFX support Shibboleth?

Yes. As of this writing (December 2003), Ex Libris and key SFX customers were participating in feasibility tests for Shibboleth. The purpose of this important new initiative from the Internet2/MACE group is to address the problems inherent in cross-domain authentication and authorization. For more information on Shibboleth, see http://shibboleth.internet2.edu/.

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What is the relationship between SFX, CrossRef, and the DOI?

CrossRef (www.crossref.org) is a consortium of primary publishers. CrossRef members use a digital object identifier (DOI; see www.doi.org) to link between their resources- for example, to link from a reference in an article published by one CrossRef member to the full text of the article itself, published by another CrossRef member.

Although it offers a persistent linking solution, DOI-based CrossRef linking does not take into account a user's affiliation and therefore does not provide for context-sensitive linking services. However, when used within the SFX framework, a DOI can deliver such context-sensitive linking services. The OpenURL framework with SFX and the CrossRef framework with DOI are compatible and complementary, and libraries that join CrossRef as affiliates can take full advantage of this synergy. CrossRef library affiliate membership is free of charge.

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How long does it take to implement an SFX server? What about maintenance?

The main work involved in implementing SFX is the localization of the preconfigured SFX resources (sources and targets) in the SFX global knowledge base, which is delivered with the SFX server. A smooth, rapid SFX implementation depends on the availability of detailed data about SFX targets, particularly the ISSNs, date ranges, and service providers for e-journal subscriptions.

Libraries can get going quite quickly with a few SFX services and then increase these as appropriate. For example, you could start with several specific resources- be they the OPAC, the Web of Science, and a few select abstracting and indexing databases- and provide links from these SFX sources to the full text of the item, the local OPAC, document-delivery or interlibrary loan services, and perhaps a Web search.

Next, you would broaden the range of SFX sources from which links may be presented and increase the range of service options. For preconfigured SFX sources- those already defined in the KnowledgeBase- this stage might simply involve a call to the information service provider to add your SFX server address to your institution's profile; or it may involve some localization. If a local data repository needs to be incorporated as an SFX source, you might have to implement the OpenURL first. Thus, the time required for configuring SFX sources varies according to the institution and the specific information resource. Ex Libris can ease the way by providing you with advice on specific resources.

With SFX, some ongoing maintenance of the KnowledgeBase is required to ensure that the links are current. Ex Libris SFX customers have found that this task does not require additional human resources but rather an effective reallocation of existing resources, particularly if the library is already dealing with linking from other vendors- for example, uploading holdings information to SilverPlatter, EBSCO, and ISI or managing library Web pages of e-journal resources. However, SFX can save libraries time and resources, particularly if a library is currently configuring links in multiple systems. With SFX, all links are configured in one place, the SFX KnowledgeBase, and are then available to all systems.

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Can I change the terminology and the order in which SFX services appear in the SFX menu?

The appearance of the SFX menu is entirely under the control of the librarian who defines and creates the services, so, yes, you can change the order of the services, the wording, and also the rules relating to specific services- for example, a rule that says not to display a document-delivery request if the electronic full text of the item is available.

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Can I suppress document-delivery links if the library subscribes to the requested resource?

Yes. For example, you can suppress links from an article retrieved from an abstracting and indexing database to a specified document-delivery service if the library already subscribes to the e-journal for the requested article.

Note also that the SFX link for a document-delivery service can be to a mediated service such as that provided by the institution's ILL department.

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What hardware platforms does the SFX link server support?

SFX can be hosted locally on a Solaris or Linux system. SFX is also available on an ASP basis.

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Is SFX available through an Ex Libris hosted server?

SFX has been available from the outset, in 2001, through the SFX subscription service hosted by Ex Libris, and many SFX customers use this service today. Sites benefit from the full power of the SFX server, including integration in the local environment, without having to host and manage this server locally.

Through the SFX subscription service,

  • Library users benefit from all the SFX services, including advanced link server features such as dynamically generated services, complex logic-display options, full statistical and reporting options, and local customization
  • Libraries can take advantage of the full range of consortium models
  • Libraries can automatically generate alphabetical e-journal lists with optional MARC record generation for loading into a local catalog
  • Libraries can choose a managed-service option to outsource the setup and ongoing configuration of their services
  • No local server installation
  • No system administration responsibilities
  • No software maintenance tasks
  • No KnowledgeBase maintenance tasks (Ex Libris carries out all updates)

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Does SFX work with any integrated library system (ILS)?

SFX operates independently of the ILS, and as of December 2003, more than 60% of SFX customers were using an ILS other than the Ex Libris ALEPH® system. For further information on a specific ILS, please contact us.

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Does SFX work in a consortium setting?

SFX is an ideal solution for a library consortium. As of December 2003, more than 70% of all SFX customers were members of a consortium. A number of models, both business and technical, are available to meet the differing needs of consortia. Factors that determine the best model for a consortium include

  • The nature of the consortium- academic, public, corporate, special, or mixed
  • The size of the consortium
  • The desired proportion of centralized control and local autonomy
  • The desired branding- consortial or institutional
  • The consortium's concept of the information landscape- shared core collections or institutional collections
  • Pricing

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How does SFX manage "dead" links?

A "dead" link can result from a number of situations, including server downtime, but typically occurs when an information provider has moved a Web resource to a new address or has changed protocols for linking to their service. A message that says "HTTP 404- File not found" is usually evidence of a dead link.

In a dynamic linking environment such as SFX, links are created on the fly when requested by a user, and powerful algorithms determine the probability of the link resource's availability. In such an environment, links are not preprocessed or verified. For each service provider participating in the SFX framework, a single global template is modified in SFX to reflect changes at an information provider's site. Thus, when a change in address occurs and is identified, the distribution of global linking templates updates the entire SFX community.

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Case Study