Handle System

The system was developed by Bob Kahn at the Corporation for National Research Initiatives (CNRI) as a part of the Digital Object Architecture (DOA).

The original work was funded by the Defense Advanced Research Projects Agency (DARPA) between 1992 and 1996, as part of a wider framework for distributed digital object services,[2] and was thus contemporaneous with the early deployment of the World Wide Web, with similar goals.

Over 1000 of these are at universities and libraries, but they are also in operation at national laboratories, research groups, government agencies, and commercial enterprises, receiving over 200 million resolution requests per month.

Older "legacy" prefixes issued by CNRI before the "multi-primary administrator" (MPA) structure was instituted are typically four of five digits, as in the second example above, a handle administered by the University of Leicester.

All prefixes must be registered in the Global Handle Registry through an DONA Foundation approved registrar, normally for a fee.

The metadata may include many attributes of the information resource, such as its locations, the forms in which it is available, the types of access (e.g. "free" versus "paid") offered, and to whom.

For example, Digital Object Identifiers, which represent a high percentage of the extant handles, are usually presented with a "doi:" prefix: doi:10.1000/182.

The Handle System website provides a series of implementation tools, notably the HANDLE.NET Software[13] and HANDLE.NET Client Libraries.

The GHR responds by sending the client the location information for the relevant Local Handle Service (which may consist of multiple servers in multiple sites); a query is then sent to the relevant server within the Local Handle Service.

The Local Handle Service returns the information needed to acquire the resource, e.g., a URL which can then be turned into an HTTP redirect.

Some applications have found it helpful to marry such a framework to the handle application: for example, the Advanced Distributed Learning (ADL) Initiative[18] brings together Handle System application with existing standards for distributed learning content, using a Shareable Content Object Reference Model (SCORM),[19] and the Digital Object Identifier (DOI) system implementation of the Handle System has adopted it together with the indecs framework to deal with semantic interoperability.

As one of the first persistent identifier schemes, the Handle System has been widely adopted by public and private institutions and proven over several years.

There are six top-level Global Handle Registry servers that receive (on average) 68 million resolution requests per month.

In 2010, CNRI and ITU (International Telecommunication Union) entered into an agreement to collaborate on use of the Handle System (and the Digital Object Architecture more generally) and are working on the specific details of that collaboration; in April 2009 ITU listed the Handle System as an "emerging trend".

By assigning persistent identifiers, companies specializing in altmetrics can effectively monitor the spread of content across social platforms and other non-traditional channels of scientific communication.

In January 2010 CNRI released its general-purpose Digital Object Repository software,[26] another major component of this architecture.

More information[27] about the release, including protocol specification, source code and ready-to-use system, clients and utilities, is available.