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59-716: 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, and was thus contemporaneous with the early deployment of the World Wide Web , with similar goals. The Handle System

118-516: A M.A. in 1962 and Ph.D. in 1964, both in electrical engineering. At Princeton, he was advised by Bede Liu and completed a doctoral dissertation titled "Some problems in the sampling and modulation of signals." He first worked at Bolt Beranek and Newman Inc. , where he was the principal designer of the ARPANET . In the fall of 1972, he demonstrated the ARPANET by connecting 20 different computers at

177-727: A half-life of nearly 23 years). A 2003 study found that on the Web, about one link out of every 200 broke each week, suggesting a half-life of 138 weeks. This rate was largely confirmed by a 2016–2017 study of links in Yahoo! Directory (which had stopped updating in 2014 after 21 years of development) that found the half-life of the directory's links to be two years. A 2004 study showed that subsets of Web links (such as those targeting specific file types or those hosted by academic institutions) could have dramatically different half-lives. The URLs selected for publication appear to have greater longevity than

236-480: A 2023 study of the Million Dollar Homepage external links, it was found that 27% of the links resulted in a site loading with no redirects, 45% of links have been redirected, and 28% returned various error messages. A 2002 study suggested that link rot within digital libraries is considerably slower than on the web, finding that about 3% of the objects were no longer accessible after one year (equating to

295-417: A dead link in the 'references' section and 23% of news articles linked to a dead URL. Link rot can result for several reasons. A target web page may be removed. The server that hosts the target page could fail, be removed from service, or relocate to a new domain name . As far back as 1999, it was noted that with the amount of material that can be stored on a hard drive, "a single disk failure could be like

354-457: A federation, using common policy or additional technology to provide shared services. 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. (See Paradigm, Persistent identifiers.) Handle System applications may use handles as simple persistent identifiers (as most commonly used, to resolve to

413-403: A fee. As with other uses of handles in computing, the handle is opaque; that is, it encodes no information about the underlying resource and provides only the means to retrieve metadata about the resource. This may be contrasted with a Uniform Resource Locator (URL), which may encode within the identifier such attributes of the resource as the protocol to be used to access the server holding

472-618: A framework to the handle application: for example, the Advanced Distributed Learning (ADL) Initiative brings together Handle System application with existing standards for distributed learning content, using a Shareable Content Object Reference Model (SCORM), 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 . The Handle System also makes explicit

531-617: A half-life of four years or greater. A 2013 study in BMC Bioinformatics analyzed nearly 15,000 links in abstracts from Thomson Reuters's Web of Science citation index and found that the median lifespan of web pages was 9.3 years, and just 62% were archived. A 2021 study of external links in New York Times articles published between 1996 and 2019 found a half-life of about 15 years (with significant variance among content topics) but noted that 13% of functional links no longer lead to

590-421: A high percentage of the extant handles, are usually presented with a "doi:" prefix: doi:10.1000/182 . Any Handle may be expressed as a Uniform Resource Locator (URL) through the use of the generic HTTP proxy server : Some Handle-based systems offer an HTTP proxy server that is intended for use with their own system such as: Implementation of the Handle System consists of Local Handle Services, each of which

649-437: A mix of objects required for a distance-learning course. There are thousands of handle services running today, located in 71 countries, on 6 continents; over 1000 of them run at universities and libraries. Handle services are being run by user federations, national laboratories, universities, computing centers, libraries (national and local), government agencies, contractors, corporations, and research groups. Major publishers use

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708-594: A namespace within the info URI scheme ; for example, 20.1000/100 may be written as the URI, info:hdl/20.1000/100 . Some Handle System namespaces, such as Digital Object Identifiers, are "info:" URI namespaces in their own right; for example, info:doi/10.1000/182 is another way of writing the handle for the current revision of the DOI Handbook as a URI. Some Handle System namespaces define special presentation rules. For example, Digital Object Identifiers , which represent

767-502: A new address or becoming permanently unavailable. A link that no longer points to its target, often called a broken , dead , or orphaned link, is a specific form of dangling pointer . The rate of link rot is a subject of study and research due to its significance to the internet 's ability to preserve information. Estimates of that rate vary dramatically between studies. Information professionals have warned that link rot could make important archival data disappear, potentially impacting

826-473: A resource. Similar to domain names, prefixes are issued to naming authorities by one of the "multi-primary administrators" of the system upon payment of a fee, which must be renewed annually. A naming authority may create any number of handles, with unique "local names", within their assigned prefixes. Two example of handles are: In the first example, which is the handle for the HANDLE.NET software license, 20.1000

885-422: A series of implementation tools, notably the HANDLE.NET Software and HANDLE.NET Client Libraries. Handle clients can be embedded in end user software (e.g., a web browser) or in server software (e.g., a web server) and extensions are already available for Adobe Acrobat and Firefox . Handle client software libraries are available in both C and Java. Some applications have developed specific add-on tools, e.g., for

944-1232: Is a recipient of the AFIPS Harry Goode Memorial Award, the Marconi Award, the ACM SIGCOMM Award, the President's Award from ACM, the IEEE Koji Kobayashi Computer and Communications Award, the IEEE Alexander Graham Bell Medal , the IEEE Third Millennium Medal, the ACM Software Systems Award , the Computerworld/Smithsonian Award, the ASIS Special Award and the Public Service Award from the Computing Research Board. He has twice received

1003-407: Is also available for users who intend to provide identifier or resolution services using the Handle System technology under the Handle System public license. The Handle System represents several components of a long-term digital object architecture. In January 2010 CNRI released its general-purpose Digital Object Repository software, another major component of this architecture. More information about

1062-433: Is available, the types of access (e.g. "free" versus "paid") offered, and to whom. The processing of the metadata to determine how and where the resource should be accessed, and the provision of the resource to the user, are performed in a separate step, called "resolution", using a Resolver, a server which may be different from the ones involved in exchanging the handle for the metadata. Unlike URLs, which may become invalid if

1121-481: Is defined in informational RFCs 3650, 3651 and 3652 of the Internet Engineering Task Force (IETF) ; it includes an open set of protocols, a namespace, and a reference implementation of the protocols. Documentation, software, and related information is provided by CNRI on a dedicated website Handles consist of a prefix which identifies a "naming authority" and a suffix which gives the "local name" of

1180-445: Is higher, authoring links that are less likely to be broken, taking steps to preserve existing links, or repairing links whose targets have been relocated or removed. The creation of URLs that will not change with time is the fundamental method of preventing link rot. Preventive planning has been championed by Tim Berners-Lee and other web pioneers. Strategies pertaining to the authorship of links include: Strategies pertaining to

1239-411: Is made up of one or more sites that provide the servers that store specific handles. The Global Handle Registry is a unique Local Handle Service which stores information on the prefixes (also known as naming authorities) within the Handle System and can be queried to find out where specific handles are stored on other Local Handle Services within this distributed system. The Handle System website provides

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1298-483: Is the prefix assigned to the naming authority (in this case, Handle.net itself) and 100 is the local name within that namespace. The local name may consist of any characters from the Unicode UCS-2 character set. The prefix also consists of any UCS-2 characters, other than "/". The prefixes consist of one or more naming authority segments, separated by periods, representing a hierarchy of naming authorities. Thus, in

1357-770: The International Conference on Computer Communications (ICCC), "the watershed event that made people suddenly realize that packet switching was a real technology." In 1972, he joined the Information Processing Techniques Office (IPTO) within DARPA . He then helped develop the TCP/IP protocols for connecting diverse computer networks. After he became director of IPTO, he started the United States government's billion dollar Strategic Computing Initiative ,

1416-490: The Transmission Control Protocol (TCP), which was intended as a replacement for an earlier network protocol, NCP , used in the ARPANET. TCP played a major role in forming the basis of internetworking , which would allow computers and networks all over the world to communicate with each other, regardless of what hardware or software the computers on each network used. To reach this goal, TCP was designed to have

1475-653: The Turing Award with Vint Cerf for their work on TCP/IP. Robert Elliot Kahn was born in December 1938 in New York to parents Beatrice Pauline (née Tashker) and Lawrence Kahn in an Ashkenazi Jewish family. Through his father, he is related to futurist Herman Kahn . After receiving a B.E.E. degree in electrical engineering from the City College of New York in 1960, Kahn went on to Princeton University where he earned

1534-542: The 1997 National Medal of Technology , the 2001 Charles Stark Draper Prize from the National Academy of Engineering , the 2002 Prince of Asturias Award, and the 2004 A. M. Turing Award from the Association for Computing Machinery. Kahn received the 2003 Digital ID World award for the Digital Object Architecture as a significant contribution (technology, policy or social) to the digital identity industry. In 2005 he

1593-681: The DOI System. The interoperable network of distributed handle resolver servers (also known as the Proxy Server System) are linked through a Global Resolver (which is one logical entity though physically decentralised and mirrored). Users of Handle System technology obtain a handle prefix created in the Global Handle Registry. The Global Handle Registry maintains and resolves the prefixes of locally maintained handle services. Any local handle service can, therefore, resolve any handle through

1652-556: The Global Resolver. Handles (identifiers) are passed by a client, as a query of the naming authority/prefix, to the Handle System's Global Handle Registry (GHR). 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

1711-472: The Handle System as an "emerging trend". Handle System, HANDLE.NET and Global Handle Registry are trademarks of the Corporation for National Research Initiatives (CNRI), a non-profit research and development corporation in the US. The Handle System is the subject of patents by CNRI, which licenses its Handle System technology through a public license, similar to an open source license, in order to enable broader use of

1770-462: The Handle System for persistent identification of commercially traded and Open Access content through its implementation with the Digital Object Identifier (DOI) system . The number of prefixes, which allow users to assign handles, is growing and stands at over 12,000 as of early 2014. There are six top-level Global Handle Registry servers that receive (on average) 68 million resolution requests per month. Proxy servers known to CNRI, passing requests to

1829-761: The Secretary of Defense Civilian Service Award. He was awarded an honorary degree by the University of Pavia in 1998. He was awarded the Stibitz-Wilson Award from the American Computer & Robotics Museum in 1999 for Pioneering the Internet through Major Design and Development Contributor to the Original ARPANET NCP Protocol and Co-Inventor of the Internet's TCP/IP Protocol. He is a recipient of

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1888-596: The University of Central Florida and the University of Pisa, and an honorary fellowship from University College, London. In 2012, he was also recognized as honorary doctor of Saint Petersburg National Research University of Information Technologies, Mechanics and Optics . Link rot Link rot (also called link death , link breaking , or reference rot ) is the phenomenon of hyperlinks tending over time to cease to point to their originally targeted file , web page , or server due to that resource being relocated to

1947-558: The application of networks to scientific research." He was awarded the 2008 Japan Prize for his work in "Information Communication Theory and Technology" (together with Vinton Cerf). The duo were also awarded with the Harold Pender Award , the highest honor awarded by the University of Pennsylvania School Engineering and Applied Sciences, in February 2010. He has also served on the board of directors for Qualcomm. In 2012, Kahn

2006-537: The average URL. A 2015 study by Weblock analyzed more than 180,000 links from references in the full-text corpora of three major open access publishers and found a half-life of about 14 years, generally confirming a 2005 study that found that half of the URLs cited in D-Lib Magazine articles were active 10 years after publication. Other studies have found higher rates of link rot in academic literature but typically suggest

2065-470: The burning of the library at Alexandria ." A domain name's registration may lapse or be transferred to another party. Some causes will result in the link failing to find any target and returning an error such as HTTP 404 . Other causes will cause a link to target content other than what was intended by the link's author. Other reasons for broken links include: Strategies for preventing link rot can focus on placing content where its likelihood of persisting

2124-590: The current URL of an object), or may choose to take advantage of other features. Its support for the simultaneous return as output of multiple pieces of current information related to the object, in defined data structures, enables priorities to be established for the order in which the multiple resolutions will be used. Handles can, therefore, resolve to different digital versions of the same content, to mirror sites, or to different business models (pay vs. free, secure vs. open, public vs. private). They can also resolve to different digital versions of differing content, such as

2183-585: The example 20 is the naming authority prefix for CNRI, while 1000 designates a subordinate naming authority within the 20 prefix. Other examples of top-level prefixes for the federated naming authorities of the DONA Foundation are 10 for DOI handles; 11 for handles assigned by the ITU ; 21 for handles issued by the German Gesellschaft für wissenschaftliche Datenverarbeitung mbH Göttingen (GWDG),

2242-400: The following features: Vint Cerf joined him on the project in the spring of 1973, and together they completed an early version of TCP. Later, the protocol was separated into two separate layers: host-to-host communication would be handled by TCP, with Internet Protocol (IP) handling internetwork communication. The two together are usually referred to as TCP/IP, and form part of the basis for

2301-506: The handles can be done in a distributed environment, similar to DNS domain names. The name-to-value bindings may also be secured, both via signatures to verify the data and via challenge response to verify the transmission of the data, allowing handles to be used in trust management applications. It is possible for the same underlying information resource to be associated with multiple handles, as when two university libraries generate handles (and therefore possibly different sets of metadata) for

2360-522: The identified entities, nor is it limited to identifying only digital objects: non-digital entities may be represented as a corresponding digital object for the purposes of digital object management. Some care is needed in the definition of such objects and how they relate to non-digital entities; there are established models that can aid in such definitions e.g., Functional Requirements for Bibliographic Records (FRBR) , CIDOC CRM , and indecs content model . Some applications have found it helpful to marry such

2419-593: The importance of organizational commitment to a persistent identifier scheme, but does not mandate one model for ensuring such commitment. Individual applications may choose to establish their own sets of rules and social infrastructure to ensure persistence (e.g., when used in the DSpace application, and the DOI application). The Handle system is designed to meet the following requirements to contribute to persistence The identifier string: The identifier resolution mechanism: Among

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2478-410: The information needed to acquire the resource, e.g., a URL which can then be turned into an HTTP redirect. (Note: if the client already has information on the appropriate LHS to query, the initial query to GHR is omitted) Though the original model from which the Handle System derives dealt with management of digital objects, the Handle System does not mandate any particular model of relationships between

2537-454: The largest computer research and development program ever undertaken by the U.S. federal government. After thirteen years with DARPA, Kahn left to found the Corporation for National Research Initiatives (CNRI) in 1986, and as of 2022 remains its chairman, CEO and president. While working on the SATNET satellite packet network project, he came up with the initial ideas for what later became

2596-469: The legal system and scholarship. Commonly, broken website links may immediately redirect the user to the home page of the website, confusing users even more and resulting in it being difficult to obtain the URL of the broken link. A number of studies have examined the prevalence of link rot within the World Wide Web , in academic literature that uses URLs to cite web content, and within digital libraries . In

2655-427: The metadata embedded within them becomes invalid, handles do not become invalid and do not need to change when locations or other metadata attributes change. This helps to prevent link rot , as changes in the information resource (such as location) need only be reflected in changes to the metadata, rather than in changes in every reference to the resource. Each handle may have its own administrator and administration of

2714-607: The modern Internet. In 1992 he co-founded with Vint Cerf the Internet Society , to provide leadership in Internet related standards, education, and policy. In 1981, Bob Kahn was elevated to the grade of IEEE fellow for original work in packet switching mobile radio telecommunications technology. He was elected as a member to the National Academy of Engineering in 1987 for research contributions in computer networks and packet switching, and for creative management contributions to research efforts in computers and communications. He

2773-478: The objects that are currently identified by handles are journal articles, technical reports, books, theses and dissertations, government documents, metadata, distributed learning content, and data sets. Handles are being used in digital watermarking applications, GRID applications, repositories, and more. Although individual users may download and use the HANDLE.NET software independently, many users have found it beneficial to collaborate in developing applications in

2832-507: The original content—a phenomenon called content drift . A 2013 study found that 49% of links in U.S. Supreme court opinions are dead. A 2023 study looking at United States COVID-19 dashboards found that 23% of the state dashboards available in February 2021 were no longer available at the previous URLs in April 2023. Pew Research found that, in 2023, 38% of pages from 2013 went missing. Also, in 2023, 54% of English Misplaced Pages articles had

2891-486: The release, including protocol specification, source code and ready-to-use system, clients and utilities, is available. Bob Kahn Bob Kahn (born December 23, 1938) is an American electrical engineer who, along with Vint Cerf , first proposed the Transmission Control Protocol (TCP) and the Internet Protocol (IP), the fundamental communication protocols at the heart of the Internet. In 2004, Kahn won

2950-411: The resource, the server host name and port number, and perhaps even location specifics such as the name of a file in the server file system containing the resource. In the Handle System, these specifics are not encoded in the handle, but are found in the metadata to which the handle is bound. The metadata may include many attributes of the information resource, such as its locations, the forms in which it

3009-552: The same book. The Handle System is compatible with the Domain Name System (DNS), but does not require it, unlike persistent identifiers such as PURLs or ARKs , which are similar to handles, but which utilise domain names. However, unlike these domain-name based approaches, handles do require a separate prefix registration process and handle servers separate from the domain name servers. Handles can be used natively, or expressed as Uniform Resource Identifiers (URIs) through

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3068-530: The scientific computing center of the University of Göttingen ; and 86 for the Coalition of Handle Services – China. 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

3127-475: The source code for reference implementations for the servers and protocols used in the system under a royalty-free "Public License", similar to an open source license. Thousands of handle services are currently running. 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. The Handle System

3186-475: The system on the Web, receive (on average) 200 million resolution requests per month. (Statistics from Handle Quick Facts.) 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

3245-550: The technology. Handle System infrastructure is supported by prefix registration and service fees, with the majority coming from single prefix holders. The largest current single contributor is the International DOI Foundation . The Public License allows commercial and non-commercial use at low cost of both its patented technology and the reference implementation of the software, and allows the software to be freely embedded in other systems and products. A Service Agreement

3304-866: Was awarded the Townsend Harris Medal from the Alumni Association of the City College of New York, the Presidential Medal of Freedom , and the C & C Prize in Tokyo, Japan. He was inducted into the National Inventors Hall of Fame in May 2006. He was inducted as a Fellow of the Computer History Museum in 2006 "for pioneering technical contributions to internetworking and for leadership in

3363-575: Was elected a Founding Fellow of Association for the Advancement of Artificial Intelligence in 1990. He was awarded the SIGCOMM Award in 1993 for "visionary technical contributions and leadership in the development of information systems technology", and shared the 2004 Turing Award with Vint Cerf, for "pioneering work on internetworking , including .. the Internet's basic communications protocols .. and for inspired leadership in networking." He

3422-630: Was first implemented in autumn 1994, and was administered and operated by CNRI until December 2015, when a new "multi-primary administrator" (MPA) mode of operation was introduced. The DONA Foundation now administers the system's Global Handle Registry and accredits MPAs, including CNRI and the International DOI Foundation . The system currently provides the underlying infrastructure for such handle-based systems as Digital Object Identifiers (DOI) and DSpace , which are mainly used to provide access to scholarly, professional and government documents and other information resources. CNRI provides specifications and

3481-570: Was inducted into the Internet Hall of Fame by the Internet Society . In 2013, Kahn was one of five Internet and Web pioneers awarded the inaugural Queen Elizabeth Prize for Engineering . Kahn received the 2024 IEEE Medal of Honor for "pioneering technical and leadership contributions in packet communication technologies and foundations of the Internet." Kahn has received honorary degrees from Princeton University, University of Pavia, ETH Zurich, University of Maryland, George Mason University,

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