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Re: Efficiently compressed XML

From: Daniel Peintner <daniel.peintner@gmail.com>
Date: Thu, 10 Dec 2009 09:49:28 +0100
Message-ID: <abbf52e10912100049g606717c6i5db893dd937565ee@mail.gmail.com>
To: "steve.williams" <steve.williams@advance-software.com>
Cc: carine <carine@w3.org>, public-exi <public-exi@w3.org>
Hello Steve,

> A few questions, if I may. Please feel free to point me at a document if
> this is all covered in the specification or an FAQ.

Thank you for interest in EXI. Please find further information and
comments inline.

> 1. Is EXI considered a replacement for FIS, or are they competing standards.
> Does the W3C have a preferred encoding ?

The intent of W3C EXI is to provide a single, interoperable standard
for the web. Prior to EXI, there were many different binary XML technologies
and standards targeted at different use cases. The goal of EXI is to address
the resulting fragmentation and non-interoperability by providing a single
standard that works well for all the W3C's use cases [1] and requirements [2].

FastInfoset is one of three different binary XML standards from ISO. It was
one of the candidate technologies considered for the W3C EXI standard, but
unfortunately it did not achieve the levels of compactness or generality
required by the W3C use cases [3]. As such, it was not selected to be the
W3C EXI standard.

> 2. A suitable data format must include support for efficiently packing
> floating point and integer arrays.
>
> I note FIS has such support, what about EXI ?

EXI provides you with efficient encodings of float and integer values
as well as plenty of other datatypes. The EXI specification [4]
describes how XML schema datatypes are represented in EXI.
You may also want to take a look at our evaluation note [5] that
highlights the benefit of the EXI format regarding compactness and
processing speed.

> 3. Is there an EXI discussion group somewhere I can join ?

Basically, there are two public mailing lists you may want to follow.

* List for technical discussions with the working group
public-exi@w3.org,
http://lists.w3.org/Archives/Public/public-exi/

* List for sending feedbacks on the EXI format specification
public-exi-comments@w3.org,
http://lists.w3.org/Archives/Public/public-exi-comments/

If not already, you can subscribe to those lists.

> 4. Is there an EXI C/C++ reference implementation ?

The W3C usually does not do reference implementations. The EXI working
group does neither work on nor plan to develop a reference
implementation.
Nevertheless, we are interested in upcoming implementations and there
are already some implementations available and we keep track of those
on our public web page [6].

Hope this helps,

-- Daniel

[1] http://www.w3.org/TR/xbc-use-cases/
[2] http://www.w3.org/TR/xbc-characterization/#N102EC
[3] http://www.w3.org/TR/exi-measurements/#contributions-assessment
[4] http://www.w3.org/TR/exi/#encodingValues
[5] http://www.w3.org/TR/exi-evaluation/
[6]  http://www.w3.org/XML/EXI/#implementations


>
> Best regards,
>
> Steve Williams
> Director
> Advance Software
>
>
>
Received on Thursday, 10 December 2009 08:50:09 GMT

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