nasyi.blogg.se - Universal generator

#Universal generator registration#
#Universal generator software#
#Universal generator code#

#Universal generator code#

The four bits of digit M are the UUID version, and the 1 to 3 most significant bits of digit N code the UUID variant. The four-bit M and the 1 to 3 bit N fields code the format of the UUID itself. In its canonical textual representation, the 16 octets of a UUID are represented as 32 hexadecimal (base-16) digits, displayed in five groups separated by hyphens, in the form 8-4-4-4-12 for a total of 36 characters (32 hexadecimal characters and 4 hyphens). The Internet Engineering Task Force (IETF) published the Standards-Track RFC 4122, technically equivalent to ITU-T Rec.

UUIDs are documented as part of ISO/ IEC 11578:1996 " Information technology – Open Systems Interconnection – Remote Procedure Call (RPC)" and more recently in ITU-T Rec.

#Universal generator software#

UUIDs are standardized by the Open Software Foundation (OSF) as part of the Distributed Computing Environment (DCE). When in July 20 was published as a proposed IETF standard, the ITU had also standardized UUIDs, based on the previous standards and early versions of RFC 4122.

RFC 4122 registered a URN namespace for UUIDs and recapitulated the earlier specifications, with the same technical content. Later, the Microsoft Windows platforms adopted the DCE design as "globally unique identifiers" (GUIDs). The initial design of DCE UUIDs was based on the NCS UUIDs, whose design was in turn inspired by the ( 64-bit) unique identifiers defined and used pervasively in Domain/OS, an operating system designed by Apollo Computer. In the 1980s Apollo Computer originally used UUIDs in the Network Computing System (NCS) and later in the Open Software Foundation's (OSF) Distributed Computing Environment (DCE).

6.4 Versions 3 and 5 (namespace name-based).

6.3 Version 2 (date-time and MAC address, DCE security version).

6.2 Version 1 (date-time and MAC address).

Information labeled with UUIDs by independent parties can therefore be later combined into a single database or transmitted on the same channel, with a negligible probability of duplication.Īdoption of UUIDs is widespread, with many computing platforms providing support for generating them and for parsing their textual representation. Thus, anyone can create a UUID and use it to identify something with near certainty that the identifier does not duplicate one that has already been, or will be, created to identify something else. While the probability that a UUID will be duplicated is not zero, it is close enough to zero to be negligible.

#Universal generator registration#

Their uniqueness does not depend on a central registration authority or coordination between the parties generating them, unlike most other numbering schemes. When generated according to the standard methods, UUIDs are, for practical purposes, unique. The term globally unique identifier ( GUID) is also used, often in software created by Microsoft. A universally unique identifier ( UUID) is a 128-bit label used for information in computer systems.