summaryrefslogtreecommitdiff
path: root/doc/rfc/rfc3718.txt
blob: b07a69a1f7cb46794a28cbf023a7204e06f10a71 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
Network Working Group                                         R. McGowan
Request for Comments: 3718                                       Unicode
Category: Informational                                    February 2004


    A Summary of Unicode Consortium Procedures, Policies, Stability,
                           and Public Access

Status of this Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2004).  All Rights Reserved.

Abstract

   This memo describes various internal workings of the Unicode
   Consortium for the benefit of participants in the IETF.  It is
   intended solely for informational purposes.  Included are discussions
   of how the decision-making bodies of the Consortium work and their
   procedures, as well as information on public access to the character
   encoding & standardization processes.

1.  Introduction

   This memo describes various internal workings of the Unicode
   Consortium for the benefit of participants in the IETF.  It is
   intended solely for informational purposes.  Included are discussions
   of how the decision-making bodies of the Consortium work and their
   procedures, as well as information on public access to the character
   encoding & standardization processes.

2.  About The Unicode Consortium

   The Unicode Consortium is a corporation.  Legally speaking, it is a
   "California Nonprofit Mutual Benefit Corporation", organized under
   section 501 C(6) of the Internal Revenue Service Code of the United
   States.  As such, it is a "business league" not focussed on profiting
   by sales or production of goods and services, but neither is it
   formally a "charitable" organization.  It is an alliance of member
   companies whose purpose is to "extend, maintain, and promote the
   Unicode Standard".  To this end, the Consortium keeps a small office,
   a few editorial and technical staff, World Wide Web presence, and
   mail list presence.



McGowan                      Informational                      [Page 1]
^L
RFC 3718      Internal Workings of the Unicode Consortium  February 2004


   The corporation is presided over by a Board of Directors who meet
   annually.  The Board is comprised of individuals who are elected
   annually by the full members for three-year terms.  The Board
   appoints Officers of the corporation to run the daily operations.

   Membership in the Consortium is open to "all corporations, other
   business entities, governmental agencies, not-for-profit
   organizations and academic institutions" who support the Consortium's
   purpose.  Formally, one class of voting membership is recognized, and
   dues-paying members are typically for-profit corporations, research
   and educational institutions, or national governments.  Each such
   full member sends representatives to meetings of the Unicode
   Technical Committee (see below), as well as to a brief annual
   Membership meeting.

3.  The Unicode Technical Committee

   The Unicode Technical Committee (UTC) is the technical decision
   making body of the Consortium.  The UTC inherited the work and prior
   decisions of the Unicode Working Group (UWG) that was active prior to
   formation of the Consortium in January 1991.

   Formally, the UTC is a technical body instituted by resolution of the
   board of directors.  Each member appoints one principal and one or
   two alternate representatives to the UTC.  UTC representatives
   frequently do, but need not, act as the ordinary member
   representatives for the purposes of the annual meeting.

   The UTC is presided over by a Chair and Vice-Chair, appointed by the
   Board of Directors for an unspecified term of service.

   The UTC meets 4 to 5 times a year to discuss proposals, additions,
   and various other technical topics.  Each meeting lasts 3 to 4 full
   days.  Meetings are held in locations decided upon by the membership,
   frequently in the San Francisco Bay Area.  There is no fee for
   participation in UTC meetings.  Agendas for meetings are not
   generally posted to any public forum, but meeting dates, locations,
   and logistics are posted well in advance on the "Unicode Calendar of
   Events" web page.

   At the discretion of the UTC chair, meetings are open to
   participation of member and liaison organizations, and to observation
   by others.  The minutes of meetings are also posted publicly on the
   "UTC Minutes" page of the Unicode Web site.

   All UTC meetings are held jointly with the INCITS Technical Committee
   L2, the body responsible for Character Code standards in the United
   States.  They constitute "ad hoc" meetings of the L2 body and are



McGowan                      Informational                      [Page 2]
^L
RFC 3718      Internal Workings of the Unicode Consortium  February 2004


   usually followed by a full meeting of the L2 committee.  Further
   information on L2 is available on the official INCITS web page.

4.  Unicode Technical Committee Procedures

   The formal procedures of the UTC are publicly available in a document
   entitled "UTC Procedures", available from the Consortium, and on the
   Unicode web site.

   Despite the invocation of Robert's Rules of Order, UTC meetings are
   conducted with relative informality in view of the highly technical
   nature of most discussions.  Meetings focus on items from a technical
   agenda organized and published by the UTC Chair prior to the meeting.
   Technical items are usually proposals in one of the following
   categories:

      1. Addition of new characters (whole scripts, additions to
         existing scripts, or other characters)

      2. Preparation and Editing of Technical Reports and Standards

      3. Changes in the semantics of specific characters

      4. Extensions to the encoding architecture and forms of use

   Note: There may also be changes to the architecture, character
   properties, or semantics.  Such changes are rare, and are always
   constrained by the "Unicode Stability Policies" posted on the Unicode
   web site.  Significant changes are undertaken in consultation with
   liaison organizations, such as W3C and IETF, which have standards
   that may be affected by such changes.  See sections 5 and 6 below.

   Typical outputs of the UTC are:

      1. The Unicode Standard, major and minor versions (including the
         Unicode Character Database)

      2. Unicode Technical Reports

      3. Stand-alone Unicode Technical Standards

      4. Formal resolutions

      5. Liaison statements and instructions to the Unicode liaisons to
         other organizations.






McGowan                      Informational                      [Page 3]
^L
RFC 3718      Internal Workings of the Unicode Consortium  February 2004


   For each technical item on the meeting agenda, the general process is
   as follows:

      1. Introduction by the topic sponsor

      2. Proposals and discussion

      3. Consensus statements or formal motions

      4. Assignment of formal actions to implement decisions

5.  Unicode Technical Committee Motions

   Technical topics of any complexity never proceed from initial
   proposal to final ratification or adoption into the standard in the
   course of one UTC meeting.  The UTC members and presiding officers
   are aware that technical changes to the standard have broad
   consequences to other standards, implementers, and end-users of the
   standard.  Input from other organizations and experts is often vital
   to the understanding of various proposals and for successful adoption
   into the standard.

   Technical topics are decided in UTC through the use of formal
   motions, either taken in meetings, or by means of thirty-day letter
   ballots.  Formal UTC motions are of two types:

      1. Simple motions

      2. Precedents

   Simple motions may pass with a simple majority constituting more than
   50 percent of the qualified voting members; or by a special majority
   constituting two-thirds or more of the qualified voting members.

   Precedents are defined, according to the UTC Procedures as either

      (A) an existing Unicode Policy, or

      (B) an explicit precedent.

   Precedents must be passed or overturned by a special majority.

   Examples of implicit precedents include:

      1. Publication of a character in the standard

      2. Published normative character properties




McGowan                      Informational                      [Page 4]
^L
RFC 3718      Internal Workings of the Unicode Consortium  February 2004


      3. Algorithms required for formal conformance

   An Explicit Precedent is a policy, procedure, encoding, algorithm, or
   other item that is established by a separate motion saying (in
   effect) that a particular prior motion establishes a precedent.

   A proposal may be passed either by a formal motion and vote, or by
   consensus.  If there is broad agreement as to the proposal, and no
   member wishes to force a vote, then the proposal passes by consensus
   and is recorded as such in the minutes.

6.  Unicode Consortium Policies

   Because the Unicode Standard is continually evolving in an attempt to
   reach the ideal of encoding "all the world's scripts", new characters
   will constantly be added.  In this sense, the standard is unstable:
   in the standard's useful lifetime, there may never be a final point
   at which no more characters are added.  Realizing this, the
   Consortium has adopted certain policies to promote and maintain
   stability of the characters that are already encoded, as well as
   laying out a Roadmap to future encodings.

   The overall policies of the Consortium with regard to encoding
   stability, as well as other issues such as privacy, are published on
   a "Unicode Consortium Policies" web page.  Deliberations and encoding
   proposals in the UTC are bound by these policies.

   The general effect of the stability policies may be stated in this
   way: once a character is encoded, it will not be moved or removed and
   its name will not be changed.  Any of those actions has the potential
   for causing obsolescence of data, and they are not permitted.  The
   canonical combining class and decompositions of characters will not
   be changed in any way that affects normalization.  In this sense,
   normalization, such as that used for International Domain Naming and
   "early normalization" for use on the World Wide Web, is fixed and
   stable for every character at the time that character is encoded.
   (Any changes that are undertaken because of outright errors in
   properties or decompositions are dealt with by means of an adjunct
   data file so that normalization stability can still be maintained by
   those who need it.)

   Once published, each version of the Unicode Standard is absolutely
   stable and will never be changed retroactively.  Implementations or
   specifications that refer to a specific version of the Unicode
   Standard can rely upon this stability.  If future versions of such
   implementations or specifications upgrade to a future version of the
   Unicode Standard, then some changes may be necessary.




McGowan                      Informational                      [Page 5]
^L
RFC 3718      Internal Workings of the Unicode Consortium  February 2004


   Property values of characters, such as directionality for the Unicode
   Bidi algorithm, may be changed between versions of the standard in
   some circumstances.  As less-well documented characters and scripts
   are encoded, the exact character properties and behavior may not be
   well known at the time the characters are first encoded.  As more
   experience is gathered in implementing the newly encoded characters,
   adjustments in the properties may become necessary.  This re-working
   is kept to a minimum.  New and old versions of the relevant property
   tables are made available on the Consortium's web site.

   Normative and some informative data about characters is kept in the
   Unicode Character Database (UCD).  The structure of many of these
   property values will not be changed.  Instead, when new properties
   are defined, the Consortium adds new files for these properties, so
   as not to affect the stability of existing implementations that use
   the values and properties defined in the existing formats and files.
   The latest version of the UCD is available on the Consortium web site
   via the "Unicode Data" heading.

   Note on data redistribution: Unlike the situation with IETF
   documents, some parts of the Unicode Character Database may have
   restrictions on their verbatim redistribution with source-code
   products.  Users should read the notices in files they intend to use
   in such products.  The information contained in the UCD may be freely
   used to create derivative works (such as programs, compressed data
   files, subroutines, data structures, etc.) that may be redistributed
   freely, but some files may not be redistributable verbatim.  Such
   restrictions on Unicode data files are never meant to prohibit or
   control the use of the data in products, but only to help ensure that
   users retrieve the latest official releases of data files when using
   the data in products.

7.  UTC and ISO (WG2)

   The character repertoire, names, and general architecture of the
   Unicode Standard are identical to the parallel international standard
   ISO/IEC 10646.  ISO/IEC 10646 only contains a small fraction of the
   semantics, properties and implementation guidelines supplied by the
   Unicode Standard and associated technical standards and reports.
   Implementations conformant to Unicode are conformant to ISO/IEC
   10646.

   ISO/IEC 10646 is maintained by the committee ISO/IEC JTC1/SC2/WG2.
   The WG2 committee is composed of national body representatives to
   ISO.  Details on the ISO organization may be found on the official
   web site of the International Organization for Standardization (ISO).





McGowan                      Informational                      [Page 6]
^L
RFC 3718      Internal Workings of the Unicode Consortium  February 2004


   Details and history of the relationship between ISO/IEC JTC1/SC2/WG2
   and Unicode, Inc. may be found in Appendix C of The Unicode Standard.
   (A PDF rendition of the most recent printed edition of the Unicode
   Standard can be found on the Unicode web site.)

   WG2 shares with UTC the policies regarding stability: WG2 neither
   removes characters nor changes their names once published.  Changes
   in both standards are closely tracked by the respective committees,
   and a very close working relationship is fostered to maintain
   synchronization between the standards.

   The Unicode Collation Algorithm (UCA) is one of a small set of other
   independent standards defined and maintained by UTC.  It is not,
   properly speaking, part of the Unicode Standard itself, but is
   separately defined in Unicode Technical Standard #10 (UTS #10).
   There is no conformance relationship between the two standards,
   except that conformance to a specific base version of the Unicode
   Standard (e.g., 4.0) is specified in a particular version of a UTS.
   The collation algorithm specified in UTS #10 is conformant to ISO/IEC
   14651, maintained by ISO/IEC JTC1/SC2, and the two organizations
   maintain a close relationship.  Beyond what is specified in ISO/IEC
   14651, the UCA contains additional constraints on collation,
   specifies additional options, and provides many more implementation
   guidelines.

8.  Process of Technical Changes to the Unicode Standard

   Changes to The Unicode Standard are of two types: architectural
   changes, and character additions.

   Most architectural changes do not affect ISO/IEC 10646, for example,
   the addition of various character properties to Unicode.  Those
   architectural changes that do affect both standards, such as
   additional UTF formats or allocation of planes, are very carefully
   coordinated by the committees.  As always, on the UTC side,
   architectural changes that establish precedents are carefully
   monitored and the above-described rules and procedures are followed.

   Additional characters for inclusion in the The Unicode Standard must
   be approved both by the UTC and by WG2.  Proposals for additional
   characters enter the standards process in one of several ways:
   through...

      1. a national body member of WG2

      2. a member company or associate of UTC

      3. directly from an individual "expert" contributor



McGowan                      Informational                      [Page 7]
^L
RFC 3718      Internal Workings of the Unicode Consortium  February 2004


   The two committees have jointly produced a "Proposal Summary Form"
   that is required to accompany all additional character proposals.
   This form may be found online at the WG2 web site, and on the Unicode
   web site along with information about "Submitting New Characters or
   Scripts".  Instructions for submitting proposals to UTC may likewise
   be found online.

   Often, submission of proposals to both committees (UTC and WG2) is
   simultaneous.  Members of UTC also frequently forward to WG2
   proposals that have been initially reviewed by UTC.

   In general, a proposal that is submitted to UTC before being
   submitted to WG2 passes through several stages:

      1. Initial presentation to UTC

      2. Review and re-drafting

      3. Forwarding to WG2 for consideration

      4. Re-drafting for technical changes

      5. Balloting for approval in UTC

      6. Re-forwarding and recommendation to WG2

      7. At least two rounds of international balloting in ISO

   About two years are required to complete this process.  Initial
   proposals most often do not include sufficient information or
   justification to be approved.  These are returned to the submitters
   with comments on how the proposal needs to be amended or extended.
   Repertoire addition proposals that are submitted to WG2 before being
   submitted to UTC are generally forwarded immediately to UTC through
   committee liaisons.  The crucial parts of the process (steps 5
   through 7 above) are never short-circuited.  A two-thirds majority in
   UTC is required for approval at step 5.

   Proposals for additional scripts are required to be coordinated with
   relevant user communities.  Often there are ad-hoc subcommittees of
   UTC or expert mail list participants who are responsible for actually
   drafting proposals, garnering community support, or representing user
   communities.

   The rounds of international balloting in step 7 have participation
   both by UTC and WG2, though UTC does not directly vote in the ISO
   process.




McGowan                      Informational                      [Page 8]
^L
RFC 3718      Internal Workings of the Unicode Consortium  February 2004


   Occasionally a proposal approved by one body is considered too
   immature for approval by the other body, and may be blocked de-facto
   by either of the two.  Only after both bodies have approved the
   additional characters do they proceed to the rounds of international
   balloting.  (The first round is a draft international standard during
   which some changes may occur, the second round is final approval
   during which only editorial changes are made.)

   This process assures that proposals for additional characters are
   mature and stable by the time they appear in a final international
   ballot.

9.  Public Access to the Character Encoding Process

   While Unicode, Inc. is a membership organization, and the final say
   in technical matters rests with UTC, the process is quite open to
   public input and scrutiny of processes and proposals.  There are many
   influential individual experts and industry groups who are not
   formally members, but whose input to the process is taken seriously
   by UTC.

   Internally, UTC maintains a mail list called the "Unicore" list,
   which carries traffic related to meetings, technical content of the
   standard, and so forth.  Members of the list are UTC representatives;
   employees and staff of member organizations (such as the Research
   Libraries Group); individual liaisons to and from other standards
   bodies (such as WG2 and IETF); and invited experts from institutions
   such as the Library of Congress and some universities.  Subscription
   to the list for external individuals is subject to "sponsorship" by
   the corporate officers.

   Unicode, Inc. also maintains a public discussion list called the
   "Unicode" list.  Subscription is open to anyone, and proceedings of
   the "Unicode" mail list are publicly archived.  Details are on the
   Consortium web site under the "Mail Lists" heading.

   Technical proposals for changes to the standard are posted to both of
   these mail lists on a regular basis.  Discussion on the public list
   may result in a written proposal being generated for a later UTC
   meeting.  Technical issues and other standardization "events" of any
   significance, such as beta releases and availability of draft
   documents, are announced and then discussed in this public forum,
   well before standardization is finalized.  From time to time, the UTC
   also publishes on the Consortium web site "Public Review Issues" to
   gather feedback and generate discussion of specific proposals whose
   impact may be unclear, or for which sufficiently broad review may not
   yet have been brought to the UTC deliberations.




McGowan                      Informational                      [Page 9]
^L
RFC 3718      Internal Workings of the Unicode Consortium  February 2004


   Anyone may make a character encoding or architectural proposal to
   UTC.  Membership in the organization is not required to submit a
   proposal.  To be taken seriously, the proposal must be framed in a
   substantial way, and be accompanied by sufficient documentation to
   warrant discussion.  Examples of proposals are easily available by
   following links from the "Proposed Characters" and "Roadmaps"
   headings on the Unicode web site.  Guidelines for proposals are also
   available under the heading "Submitting Proposals".

   In general, proposals are publicly aired on the "Unicode" mail list,
   sometimes for a long period, prior to formal submission.  Generally
   this is of benefit to the proposer as it tends to reduce the number
   of times the proposal is sent back for clarification or with requests
   for additional information.  Once a proposal reaches the stage of
   being ready for discussion by UTC, the proposer will have received
   contact through the public mail list with one or more UTC members
   willing to explain or defend it in a UTC meeting.

10.  Acknowledgements

   Thanks to Mark Davis, Simon Josefsson, and Ken Whistler for their
   extensive review and feedback on previous versions of this document.

11.  Security Considerations

   This memo describes the operational procedures of an organization;
   the procedures themselves have no consequences for Internet Security.

12.  Author's Address

   Rick McGowan
   c/o The Unicode Consortium
   P.O. Box 391476
   Mountain View, CA 94039-1476
   U.S.A.

   Phone:   +1-650-693-3921
   Web: http://www.unicode.org/













McGowan                      Informational                     [Page 10]
^L
RFC 3718      Internal Workings of the Unicode Consortium  February 2004


13.  Full Copyright Statement

   Copyright (C) The Internet Society (2004).  This document is subject
   to the rights, licenses and restrictions contained in BCP 78 and
   except as set forth therein, the authors retain all their rights.

   This document and the information contained herein are provided on an
   "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
   OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
   ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
   INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
   INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
   WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Intellectual Property

   The IETF takes no position regarding the validity or scope of any
   Intellectual Property Rights or other rights that might be claimed to
   pertain to the implementation or use of the technology described in
   this document or the extent to which any license under such rights
   might or might not be available; nor does it represent that it has
   made any independent effort to identify any such rights.  Information
   on the procedures with respect to rights in RFC documents can be
   found in BCP 78 and BCP 79.

   Copies of IPR disclosures made to the IETF Secretariat and any
   assurances of licenses to be made available, or the result of an
   attempt made to obtain a general license or permission for the use of
   such proprietary rights by implementers or users of this
   specification can be obtained from the IETF on-line IPR repository at
   http://www.ietf.org/ipr.

   The IETF invites any interested party to bring to its attention any
   copyrights, patents or patent applications, or other proprietary
   rights that may cover technology that may be required to implement
   this standard.  Please address the information to the IETF at ietf-
   ipr@ietf.org.

Acknowledgement

   Funding for the RFC Editor function is currently provided by the
   Internet Society.









McGowan                      Informational                     [Page 11]
^L