Re: [OT] non-terrestrial writing systems

From: Andrew West (
Date: Tue Jun 05 2007 - 04:26:55 CDT

  • Next message: Philippe Verdy: "RE: [OT] non-terrestrial writing systems"

    On 05/06/07, Doug Ewell <> wrote:
    > Back in the day when ISO 10646 was still 31 bits wide and the proposal was
    > made to limit it to 17 planes, as Unicode already was, there were quite a
    > few, apparently serious, objections that this would be a regrettable,
    > Y2K-like limitation because of the eventual discovery of non-terrestrial
    > scripts that would need the extra coding space.

    This is not just ancient history. At the Xiamen 2005 WG2 meeting this
    issue was debated quite vigorously, with Japan resolutely against
    restricting 10646 to 17 planes ... although no-one mentioned
    extra-terrestrial writing systems as far as I remember. The discussion
    on this issue in the minutes
    (<> section 8.4),
    although somewhat condensed, is worth reading:

    8.4 Seventeen Plane Restriction
    Input document:
    2920 Seventeen planes restriction; USNB, Michel Suignard; 2005-01-25
    Dr. Asmus Freytag: The background to the request is that there is a
    perception that ISO/IEC 10646 and Unicode are not fully synchronized.
    In ISO/IEC 10646 one can talk about planes outside Unicode … even
    though all other planes in the standard are permanently reserved. The
    goal is to add text to the standard towards eliminating the perception
    of this difference.
    a. Mr. Mike Ksar: There was a similar input in one of the previous
    meetings from Mr. Zhang Zhoucai, China. It is not just the US /
    Unicode input.
    b. Dr. Ken Whistler: The wording of the third bullet is the key. We
    already had language in the standard. It spells out what is
    permanently reserved in the standard.
    c. Mr. Masahiro Sekiguchi: I am hearing from user communities in Japan
    that 17 planes are not sufficient. It is important that ISO/IEC 10646
    allows for more characters. It may not be our intent to use beyond the
    17 planes.
    d. Dr. Ken Whistler: This kind of concerns is raised in a lot of
    forums. The change is requested to address such concerns. Characters
    cannot get into the standard without approval from this committee.
    There are about 800 000 character positions unassigned. It may take
    about 800 years to reach the limit at the rate we are adding
    characters now. I don't think it is appropriate to signal to the user
    community that this committee leaves the de-synchronization open.
    e. Mr. Michael Everson: Irish position is that a limitation is
    reasonable, until the 17 planes are filled. At that time if we need
    the space we can look at it.
    f. Mr. Masahiro Sekiguchi: The users feel that 17 planes are not
    sufficient. I am not objecting to the idea to state that ISO/IEC 10646
    will not add characters that cannot be addressed also by the Unicode
    standard. At this time I do not have alternate text.
    g. Dr. Umamaheswaran: One thing we should keep in mind that UTF-16
    already has an upper limit of end of Plane 16. If we do not restrict
    beyond that limit, there will be a potential inconsistency in the
    h. Dr. Ken Whistler: The best way in the standardese of ISO/IEC 10646
    is to state that the code positions beyond the limit are Permanently
    Reserved. The octets are still there; the planes are still there from
    architecture point of view.
    i. Mr. Taichi Kawabata: PUA has only two planes and a few rows. There
    may be user groups who want to use these planes for private use
    purposes. 17 planes may not be enough.
    j. Mr. Mike Ksar: The editor has taken the material out of the
    Amendment 1 ballot comments from the US. I would suggest that the
    proposed text be accepted for inclusion in Amendment 2. The national
    bodies can propose alternate wordings to be able to improve on the
    text during ballot response.
    k. Mr. Michel Suignard: The important point is the comment you made
    about the characters the user makes. One could do whatever someone
    wants in the UCS 4 space.
    l. Mr. Masahiro Sekiguchi: I want to promote ISO/IEC 10646. Some
    people are emotionally objecting to the limited code space. I hear
    that 20 bits are not enough.
    m. Mr. Mike Ksar: The architecture is not changing. Would like to have
    backed up rationale if the proposed text is not adequate.
    n. Mr. Masahiro Sekiguchi: The difficulty I have with the proposal ---
    is only in terms of how to word in such a way that we can address our
    o. Mr. Michel Suignard: Document N2920 contains terms that need to be updated.
    Disposition: Accept document N2920 in principle for inclusion in Amendment 2.
    Relevant resolution:
    M46.12 (17-plane restriction): Abstention: Japan
    Approval: Canada, China, Ireland, Korea (Republic of), Mongolia,
    Poland and the USA
    WG2 accepts in principle the recommendation to permanently reserve all
    code positions beyond Plane 16 from document N2920 and instructs its
    editor to prepare appropriate text and include it in Amendment 2 to
    ISO/IEC 10646: 2003.

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