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Abstract

Many protocols and systems for document search and retrieval are currently in use, and many more protocols or refinements of existing protocols are to be expected in a field whose expansion is explosive.

These systems are aiming to achieve global search and readership of documents across differing computing platforms, and despite a plethora of protocols and data formats. As protocols evolve, gateways can allow global access to remain possible. As data formats evolve, format conversion programs can preserve global access. There is one area, however, in which it is impractical to make conversions, and that is in the names and addresses used to identify objects. This is because names and addresses of objects are passed on in so many ways, from the backs of envelopes to hypertext objects, and may have a long life.

A common feature of almost all the data models of past and proposed systems is something which can be mapped onto a concept of "object" and some kind of name, address, or identifier for that object. One can therefore define a set of name spaces in which these objects can be said to exist.

Practical systems need to access and mix objects which are part of different existing and proposed systems.

This paper discusses the requirements on a universal syntax (URI) which can be used to encapsulate a name in any registered name space. This will allow names in different spaces to be treated in a common way, even though names in different spaces have differing characteristics, as do the objects to which they refer

The universal syntax allows access of objects available using existing protocols, and may be extended with technology. This document makes a recommendation for a generic syntax (URI), and for specific forms for "Uniform Resource Locators" (URLs) of objects accessible using existing Internet protocols.

The syntax has been in widespread use by World-Wide Web software since 1990.