Hi Dave,
Take a look at "A UUID URN Namespace":
ftp://ftp.ietf.org/internet-drafts/draft-mealling-uuid-urn-00.txt
(Note that this registration comes from the ISO JTC1 folks, this
is solid).
Numerous examples, and implementation details.
Cheers,
- Ira McDonald
High North Inc
------------------------------------------------------------------
[exerpts from "A UUID URN Namespace" draft]
Abstract
This specification defines a Uniform Resource Name namespace for
UUIDs ( (Universally Unique IDentifier), also known as GUIDs
(Globally Unique IDentifier). A UUID is 128 bits long, and if
generated according to the one of the mechanisms in this document, is
either guaranteed to be different from all other UUIDs/GUIDs
generated until 3400 A.D. or extremely likely to be different
(depending on the mechanism chosen). UUIDs were originally used in
the Network Computing System (NCS) [1] and later in the Open Software
Foundation's (OSF) Distributed Computing Environment [2].
This specification is derived from the latter specification with the
kind permission of the OSF. The original version of this document
was written by Paul Leach and Rich Salz but was unpublished for
several years. This is an updated version incorporated as part of
the URN registration document.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Namespace Registration Template . . . . . . . . . . . . . . 4
4. Specification . . . . . . . . . . . . . . . . . . . . . . . 7
4.1 Format . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4.1.1 Variant . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4.1.2 UUID Layout . . . . . . . . . . . . . . . . . . . . . . . . 8
4.1.3 Version . . . . . . . . . . . . . . . . . . . . . . . . . . 9
4.1.4 Timestamp . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.1.5 Clock sequence . . . . . . . . . . . . . . . . . . . . . . . 10
4.1.6 Node . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.1.7 Nil UUID . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.2 Algorithms for creating a time-based UUID . . . . . . . . . 12
4.2.1 Basic algorithm . . . . . . . . . . . . . . . . . . . . . . 12
4.2.2 Reading stable storage . . . . . . . . . . . . . . . . . . . 13
4.2.3 System clock resolution . . . . . . . . . . . . . . . . . . 13
4.2.4 Writing stable storage . . . . . . . . . . . . . . . . . . . 14
4.2.5 Sharing state across processes . . . . . . . . . . . . . . . 14
4.2.6 UUID Generation details . . . . . . . . . . . . . . . . . . 14
4.3 Algorithm for creating a name-based UUID . . . . . . . . . . 15
5. Algorithms for creating a UUID from truly random or
pseudo-random numbers . . . . . . . . . . . . . . . . . . . 16
6. Byte order of UUIDs . . . . . . . . . . . . . . . . . . . . 17
7. Node IDs when no IEEE 802 network card is available . . . . 17
8. Obtaining IEEE 802 addresses . . . . . . . . . . . . . . . . 19
9. Community Considerations . . . . . . . . . . . . . . . . . . 19
10. Security Considerations . . . . . . . . . . . . . . . . . . 20
11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 20
Normative References . . . . . . . . . . . . . . . . . . . . 20
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . 21
A. Appendix A - UUID Sample Implementation . . . . . . . . . . 21
B. Appendix B - Sample output of utest . . . . . . . . . . . . 33
C. Appendix C - Some name space IDs . . . . . . . . . . . . . . 33
Full Copyright Statement . . . . . . . . . . . . . . . . . . 35
-----Original Message-----
From: HALL,DAVID (HP-Vancouver,ex1) [mailto:dhall@hp.com]
Sent: Wednesday, December 04, 2002 10:47 AM
To: 'McDonald, Ira'
Subject: URI GUID example
Hey Ira...
We're moving forward with the sample implementation, and are having a hard
time figuring out what a String representation of a GUID would be...
Do you have a link to, or can you make some examples?
Would it look like this:?
GUID://myserver.mydomain/{12321-23123-231adfe-321f}
Thanks!
Dave
This archive was generated by hypermail 2b29 : Wed Dec 04 2002 - 15:27:37 EST