OOXML

Four Shorts

2006/08/21 By Rob 2 Comments

I. OpenOffice.org Conference (OOOoCon 2006) in comming up, September 11-13th in Lyon, France. The last day starts with a panel discussion of ODF topics, and follows with a track dedicated to ODF. I’m on at 14:00 with a presentation with the exciting title, “A Technical Comparison: ISO/IEC 26300 vs Microsoft Office Open XML (Ecma International TC45 OOXML WD 1.3)”.

The abstract is:

Two XML office file formats have been pressing upon our attention, the OASIS OpenDocument Format, recently standardized by ISO, and the Draft Ecma Office Open XML. This presentation will review history of each, the process that created them, and examine each format to compare and contrast how they deal with issues such extensibility, modularization, expressivity, performance, reuse of standards, programability, ease of use, and application/OS neutrality.

II. KDE enthusiasts get together two weeks later, in Dublin, for their aKademy 2006. Tuesday the 26th will be OpenDocument Day. I’ll be there, and will give a lighting talk on something, probably related to some ODF programmability API ideas I’ve been having.

III. If you didn’t see it yet, Rick “Schemetron” Jelliffe has an interesting post over at O’Reilly looking at ODF and OOXML documents from the perspective of XML complexity metrics. This is a topic which Rick has done a good deal of work with in the past, so it is interesting to hear what he has to say. Did I see something there about OpenOffice loading documents faster than Office?

IV. The ODF Formula Subcommittee has set up a wiki page on our work defining OpenFormula. A lot of good information is there. This page will be updated with the latest status, so you’ll want to make it the first place to go for the latest info on our progress.

Math You Can’t Use

2006/08/06 By Rob 13 Comments

Summary: In this post I will look at MathML, a web standard for displaying mathematical equations. I will show how well established it is on the web, how it is integrated into ODF, and how Microsoft has decided to go off in another direction with OMML, another “stealth” standard hidden in their 4,000 page Office Open XML specfication, but little mentioned. As I did with my prior analysis of their reliance on the rejected VML specification, I will show why this is a bad thing.

I’ve been reading Math You Can’t Use: Patents, Copyright, and Software a book by Ben Klemens, Guest Scholar at the Brookings Institute. It examines the current state of software patents in U.S. and the abuses thereof. He blends his legal and economic policy background with his insights as a programmer to give a perspective worth hearing. Mind you, I don’t agree with him on many points, and in fact I found the book infuriating at times, but he does make a serious argument and I respect that. In any case I like to have my opinions challenged every now and then. It keeps the mind limber.

Although I am not going to talk about patents and copyrights today, I will steal the title of this book and talk a bit about math, the kind you can use as well as the type you can’t. The topic for today is MathML.

MathML is a web standard from the W3C, an XML vocabulary for representing the structure and content of mathematical expressions. In other words, it represents equations for display, especially complicated expressions with integrals, summations, products, limits and all the Greek you can throw at it.

If you are running Firefox and have installed the math fonts then you can get an idea of its capabilities by loading MathML-enabled pages right now, like this one. If you are running Internet Explorer, then sadly you lack native support for MathML, but a browser plugin is available.

MathML 1.0 dates back to 1999, and has been revised through MathML 2.0 (second edition) in 2003.

There are about 100 implementations of MathML if you count producers, consumers and editors, including the powerful software used by working mathematicians and scientists like Maple and Mathematica.

The W3C has made a special effort to get the various MathML vendors together to evaluate how well they handle MathML and this is reported out in their Implementation and Interoperability Report .

Where MathML is supported natively, such as in Firefox, it will render along with the text, and not merely as an embedded GIF image. So, it will scale to different screen resolutions and print well. In theory, since it is just text markup in the page, it can be indexed by an intelligent search engine, though I am aware of none that do this currently. (Is there any use for a Google search of all web pages that include a 3rd degree polynomial inequality? I wouldn’t want to be the first to say “No”.)

MathML also is the key to enabling better support for mathematics via screen readers and other assistive agents. When a visually impaired user is presented an equation in the form of a GIF or other image format, they are left out. But put the formula in MathML and the possibilities look better. The work is not complete yet, but progress is being made. For example this report from CSUN 2004 and NIDE’s MathML Accessibility Project.

Further innovations are seen at sites like Wolfram’s MathMLCentral where we see web services for creating, displaying, or even integrating MathML expressions, using their Mathematica program as the backend.

For the above, and many other reasons, MathML was the only logical choice for us to use to support equations in OpenDocument Format (ODF). With such a thriving ecosystem of producers and consumers, with support the tools used by academia and industry like Mathematica and Maple, strong support in web browsers like Firefox, with the accessibility initiatives around it, I don’t see how you could argue otherwise. MathML is the way the web does math.

But the choice of MathML is more than just a fashion statement. It has practical significance and enables opportunities for innovative workflows around mathematical document production. If you create an equation block in OpenOffice, it saves the equation as a standalone MathML XML document in the ODT document archive. This makes it very easy to access, read, replace, etc.

We should be thinking about workflows like the following:

Do your complicated calculations in a tool like Mathematica
When you get the final results you want, export it to MathML, for example, using Mathematica’s MathMLForm[ ] function.
Copy the MathML into an ODF document archive
Take the ODF document and complete the prose write-up of the document in OpenOffice
Share the draft with colleagues, review, etc., in the editable ODF format
When ready to publish, export to XHTML with embedded MathML preserved for the equations, and embedded SVG for the charts.
Users can then view in Firefox or Internet Explorer (with extra plugin)

We’re not quite there yet, end to end. Step #6 in particular is not working as I’d expect in OpenOffice 2.03. But you get the idea. There is opportunity for fame glory and perhaps some profit to the person or company who provides an end-to-end mathematical editing and publishing solution based on open standards.

So, in this happy world I’ve described, what is missing? If you guessed “Microsoft Office” then you guessed correctly! Even though MathML is a 7 year-old standard, widely implemented, supported by the leading mathematical tools, the preferred format for publishing math on the web, etc, etc., (the mantra should be familiar), Microsoft has ignored it and instead is pushing forward a new competing format in their Office Open XML (OOXML) specification rushing through Ecma.

The new math markup format is called OMML and you’ve probably never heard of it. You can check Google, you can check Wikipedia, you can check MSDN. You won’t find it. In fact, I’m not even sure what OMML stands for since the acronym is not defined in the spec. But it is there, nestled away in the 4,081 page draft OOXML specification as the markup that “specifies the structures and appearance of equations in the document”, Section 25.1, all 93 pages of it.

OMML is not MathML, though it does the solves the same problem. But if you use OMML, it will not work with Firefox, with Mathematica, with OpenOffice or with any of the other 100 applications that support MathML. OMML works with Office, and that’s it. One door in, no doors out.

Consider that Ecma TC45’s Programme of Work included the goal of:

….enabling the implementation of the Office Open XML Formats by a wide set of tools and platforms in order to foster interoperability across office productivity applications and with line-of-business systems.

How exactly does the OOXML specification foster this interoperability when it ignores relevant web standards like MathML (and SVG and XForms)?

Microsoft’s typical argument is to say that the existing standards are inadequate, that Microsoft users expect more, that they need more features, that this is because they need to deal with billions of documents and trillions of dollars, etc. But this rings hollow when talking about math. An examination of the history of mathematical notation demonstrates, as you may already know, that mathematical notation is not exactly experiencing a high rate-of-change. Equations, as used in math and sciences, for the most part use the same notation they did 100 years ago, and many parts of notation are 200-300 years old. Certainly there is no essential change in notation since 1999, when MathML was created.

Now if Microsoft had merely wanted to create a proprietary format for equations and use that in Word in order to trap their customers onto that platform, then I’d simply say that’s not my concern and I’d blog about my heirloom tomatoes or something else. But when this shows up in a nominally open standard destined for approval by ISO, then this raises my eyebrows a little. The obvious choice would have been to simply reuse MathML. So, why are they creating, and standardizing a whole new math markup language? Are there no standards worth reusing? Will XPS replace PDF, VML replace SVG, Windows Media Photo format replace PNG, OMML replace MathML, and OOXML replace ODF? Let’s say “No” to OMML and “Yes” to MathML, the math you can use.

Follow the Leader

2006/08/03 By Rob 13 Comments

David Wheeler, the chair of the OASIS ODF Formula Subcommittee has a good status update on our work defining the details of the expression language and supporting functions used in spreadsheet formulas. I’d also like to point out some cool work by Daniel Carrera, who put together some code that post-processes the OpenFormula specification (in ODF format, of course), extracts the details of the embedded test cases, then automatically generates an ODF spreadsheet file which executes the spreadsheet functions and verifies correct results. This resulting spreadsheet allows an implementation to automatically test their compliance to the spec. This gives us a self-testing specification, a great labor savings, as well as a demonstration of the innovative things you can do with ODF. Details are here.

(I note in passing that although the OASIS ODF TC does all of its working documents in ODF format, the Ecma TC45 does none of its working documents in OOXML. They continue to use the old proprietary Microsoft binary formats as their working format on the TC. A suggestion — If they are unable for some reason to use OOXML, then I encourage TC45 to use ISO ODF. They can then download Daniel’s code to help generate test cases from their spreadsheet formula documentation and this, I promise you, will save implementors a lot of time.)

Of course, malcontents will never be pleased by our progress, and will portray this progress as proof that we are yet imperfect, and therefore not useful. The first point is obvious, but the second is dubious.

Stephen McGibbon’s blog entry of a couple weeks ago seems to be the Urquelle of this particular line of reasoning. Here’s one small quote:

I mentioned that in my opinion, Sun were completely aware that ODF wasn’t sufficiently defined to support spreadsheet interoperability as long ago as February 2005 and that the realpolitik inside OASIS was to take advantage of the EU IDA’s request to standardise by rushing to be first despite knowing the ODF specification was deficient in at least this area.

Read the rest of his article and you’ll walk away with two misconceptions:

The lack of a spreadsheet formula definition in a file format documentation is unusual, defective and prevents interoperability
Spreadsheet formulas were left out because ODF standardization was rushed, for political reasons

Let’s take a look at each of these in turn.

First, let’s look at the state of the art in spreadsheet file format documentation over the years, with particular attention to how spreadsheet formulas have been documented. As the following table shows, Excel formulas have never been publicly specified, even though Microsoft has been producing file format documentation for various binary, HTML, XHTML and XML Excel formats for over 9 years. It was only after the ODF TC decided to document our spreadsheet formulas and formed a Subcommittee to do so that Ecma TC45 decided to follow. The FUD followed soon after.

Date	Format version	Formula status
1997	Excel 97 Developers Kit (Microsoft Press, 1997)	not defined
ca 1998	MSDN CD’s in this era had Office file format documentation	not defined
Jan 1999	Office 2000’s XHTML formats for Excel	not defined
May 2001	Office XP’s XMLSS format for spreadsheets	not defined
Nov 2003	Office 2003’s XML Schemas	not defined
Dec 2005	Microsoft submits initial “base document” to Ecma	not defined
January 2006	Ecma TC45’s Working Draft 1.1	not defined
February 2006	The OASIS ODF Formula Subcommittee is formed to add formula definition to the ODF specification
April 2006	Ecma TC45’s Working Draft 1.2	not defined
May 2006	Ecma TC45’s Working Draft 1.3	Mirabile dictu! After 9 years of ignoring it, Microsoft finally decides to start defining their spreadsheet formula language.

So the statement that the lack of a formula language specification is unusual or makes interoperability impossible falls down in the face of 9 years of contrary evidence. Over the years, the industry has managed to have interoperable spreadsheet formulas between different versions of Office as well as between Excel and competing spreadsheets, including 1-2-3, Quattro Pro, OpenOffice, StarOffice, etc., all without ever having a formula specification.

Even though every other spreadsheet file format specification in the past decade failed to document a spreadsheet formula language, the ODF TC knew that we could and should do better. That is why we took the lead and formed a Subcommittee to define, in great detail, with test cases, how spreadsheet formulas, expressions and functions should be interpreted. This is not fixing a problem. This is advancing the state of the art in file format specifications.

They say that imitation is the sincerest form of flattery. If so the ODF community should be blushing with all of this flattery heaped on it. If it wasn’t for the continual market pressure that our innovations bring, Microsoft would never have 1) issued a patent covenant for OOXML, 2)brought OOXML before a standards body, 3) started to document their spreadsheet formula language or 4) started to create an ODF Add-in for Office.

So, then what about the statement that ODF was rushed through the standardization process?

Let’s look at the numbers. Both ODF and OOXML are derived from pre-existing formats . This is not necessarily a bad thing. This is one source of “implementation experience” and this is beneficial to any standard to have this. But only once the “base document” is submitted to a multi-vendor open standards development organization (SDO) does the true work of standardization begin, including deep technical review of the specification to confirm completeness, conciseness, lack of ambiguity, correct use of formal specification language, ensuring platform independence, encourage flexibility and extensibility, etc. So, I’ll start the clock when the base specification is submitted to the SDO, and stop the clock when the SDO approves the standard.

The ODF numbers are clear enough since the 1.0 version is complete. The OOXML numbers require some estimation, since they are not complete, but I’ll justify my estimates this way:

The OOXML Working Draft 1.3 is currently 4,081 pages long. At the SC34 meeting in June we were told by the Ecma Secretary General that more material was coming and that this draft was only 2/3 complete. By my calculations, this gives a final size estimate of around 6,000 pages.
Predicting the completion date is harder. But we do know that Ecma specifications can only be approved twice a year at Ecma General Assembly which are in June and December. If I were Microsoft I’d really really really want OOXML approved in time for the Office 2007 launch, so I’m predicting Ecma approval will be sought at the December Ecma General Assembly.

Of course I could be wrong on either or both of those estimates, but let’s see where the logic takes us. The following table summarizes the time under standardization as well as the rate of standardization (pages/day) for each specification.

Standard	Submitted to SDO	Standard issued	Days elapsed	Standard length	Rate of work
ODF	12 Dec 2002	1 May 2005	867	706 pages	0.8 pages/day
OOXML	15 Dec 2005	31 Dec 2006 (est)	381 (est)	6000 pages (est)	15.6 pages/day (est)

Now I ask you, who is rushing? ODF took 2 ½ years to standardize 700 pages. Microsoft is trying to standardize a 6,000 page behemoth in just 1 year. I think the argument that ODF was rushed through under political pressure just doesn’t stand up to even cursory examination. Honestly, I think this FUD is being spread around as a smoke screen to hide the fact that OOXML is the one that is really being rushed.

Throwing stones at people in glass houses

2006/07/27 By Rob 9 Comments

I work in a house with glass walls. Not literally, of course. The cost to air-condition such a house would be prohibitive. I mean that working on standard in OASIS is a public act, with process transparency and public visibility. The public doesn’t see merely the end-product, or quarterly drafts, they can see (if they are so inclined) every discussion, every disagreement and every decision made by the TC, in near real-time. Our meeting minutes for our TC calls are posted for public inspection. Our mailing list archives, where most of the real work occurs, is there for the public to view. The comments submitted by the public are also available for anyone to read. This information is all archived from when the TC first met back in 2002, all the way to the discussions we’re having today on spreadsheet formula namespaces.

One result of this openness is that it is very easy, trivial even, for our critics to simply read our mailing list, look for a disagreement or discussion of an issue, and repeat our words, usually out of context. Cut & Paste. This is certainly the most efficient way to criticize ODF since it minimizes the amount of thinking required. However, this is a bit tedious, especially when this is applied so asymmetrically, as I shall now explain.

Ecma TC45, the committee producing Office Open XML (OOXML), does not operate in such a transparent manner. They do not have a public mailing list archive. They have not published their meeting minutes. The comments they receive from the public are not open for the public to read. The public has no idea what exactly the TC is working on, what issues they think are critical, whether the TC is in unanimous agreement, whether there is spirited debated or whether Microsoft dominates and determines everything. The fact that they have not yet sent OOXML for an Ecma vote is proof that believe the specification is not yet ready for standardization. But we know no details of what exactly is lacking, what problems are being fixed or, more importantly, what defects are being allowed to remain.

And in this way, the ODF-bashers take advantage of our openness, while holding their deliberations in obscurity. They throw rocks at our glass house while hiding in the shadows.

So this openness at OASIS has an apparent downside. But honestly, I wouldn’t trade it for any alternative. Making a standard, especially one this important, is a privilege, not a right. The public deserves to know how a standard is made, the same way and for the same reasons they deserve to know how legislation is made. I relish this scrutiny because I know it makes us stronger.

Sun’s Simon Phipps has posted his keynote from the recent OSCON conference. The topic was the “Zen of Free” and, among other goodies, Phipps lists 5 requirements for “full support for fully open standards”, of which I quote the 4th, since it states the point better than I have:

…the standard [Phipps here speaking generically and not about any specific standard] should have been created transparently. Just as an open source community looks with concern on a large, monolithic code contribution, so we should be wary of standards created without the opportunity for everyone to participate or, failing that, with a full explanation of every decision that was made in its construction. Without that there’s a chance that it’s designed to mesh with some facility or product that will be used to remove our freedom later.

Another way to attack openness is to do it with legal restrictions. For example, we’re seeing many references to a year-old performance evaluation of an atypical spreadsheet file, and using that to make the ridiculous claim that the ODF format itself is too slow. I’d love to dispute that claim and show it for what it is. I’d love to show that for most common document sizes, ODF documents are actually smaller and faster to load and save than OOXML documents. I’d love to show you all this, but I can’t. Why? Because Microsoft won’t let me. The only implementation of OOXML is the Office 2007 beta, and the End User License Agreement (EULA) has this language:

7. SCOPE OF LICENSE. …You may not disclose the results of any benchmark tests of the software to any third party without Microsoft’s prior written approval

So, our critics can quote benchmark results about ODF running in OpenOffice, but we can’t quote numbers about OOXML running in Office. They can read our mailing lists and quote us discussing ODF issues as we address them, but we cannot even see what they are working on.

What should we make of all this? I suggest that no specification is perfect. That’s why we have version numbers. The question you need to ask yourself is: what leads to a better specification, full and open public discussion and scrutiny? Or something rushed through behind closed doors? You know what the issues with ODF are, and you’ll continue to hear the same small list over and over again. But this is a shrinking list, as the ODF TC experts address these issues. But do you know what the issues with OOXML are, the reasons why Ecma TC45 has not yet put forward their specification as an Ecma standard? What do their experts say when speaking candidly about their specification? The public simply doesn’t not know. Do we assume silence means perfection? I don’t think so.

VML and OOXML: Cum mortuis in lingua mortua

2006/07/24 By Rob 7 Comments

In this post, I will look at the history of Vector Markup Language (VML), how it lost out to the W3C’s SVG back in the 1990’s, but has come back from the dead, showing up in the draft Ecma Office Open XML (OOXML) specification. I offer some opinions on why this is a bad thing.

First, a bit of history. The field is vector graphics, the type of graphics composed of lines and shapes and background fills, the type of graphics that scales nicely to different sizes/resolutions, and different devices, as opposed to raster graphics which is a bunch of pixels such as a GIF or JPEG file. This is a gross oversimplification, but it will suffice.

Vector Markup Language (VML) was an XML vocabulary for vector graphics submitted to the W3C by Microsoft and others back in mid-1998. I will not comment on its quality or merits, but merely note that it was rejected by the W3C in favor of Scalable Vector Graphics (SVG) specification which became a W3C Recommendation (that’s what the W3C calls their standards) in 2001. Since then, SVG 1.0 was upgraded to SVG 1.1. in 2003 and several mobile profiles (SVG Tiny and SVG Basic) were created. SVG has native support in Firefox and Opera, with Plugins available for most other browsers. There is support on mobile phones and PDA’s. A search of Amazon.com shows 19 books dedicated to SVG. The SVGOpen Conference has been going for 5 years strong. This all adds up to SVG being an established, open standard, widely implemented with a thriving implementor/user community and signs of continued innovation. It is a standard with a past, a present and a future.

But what ever happened to VML? VML has been a dead-end, from a standards perspective, for 8 years now, an eternity in web time. I was not able to find any VML books on Amazon. I could not find any VML conferences (unless one counts the Virgina Municipal League’s get-together at Virgina Beach in October). However, there is some lingering VML support in Internet Explorer and Office. Developers still use VML to target those applications, but I wonder, is it done out of preference or out of necessity? Although it is the users who are portrayed as dinosaurs for not upgrading to Office 2003, doesn’t it seem like Microsoft Office and Internet Explorer are the ones in need of an upgrade? They should join the rest of the world and start using SVG rather dragging along a dead spec.

But it is worse than this. I wouldn’t have bothered writing this just to point out something you already know, that Internet Explorer slowly or never adopts relevant web standards. The thing I wish to bring to your attention is that VML, the same VML rejected in 1998, is now being proposed as part of the draft Ecma Office Open XML. Take a look for yourself (warning, 25 MB specification download!).

Section 8.6.2 of the spec (Ecma Office Open XML, Working Draft 1.3) says:

VML specifies the appearance and content of certain shapes in a document. This is used for shapes such as text boxes, as well as shapes which must be stored to maintain compatibility with earlier versions of consumer/producer applications.

How should one parse “earlier versions of consumer/producer applications”? Is this a circuitous way of saying “MS Office and Internet Explorer”?

Now take a look at Chapter 23, VML, pages 3571-3795 (PDF pages 3669-3893). We see here 224 pages of “VML Reference Material”, which appears to be a rehash of the 1999 VML Reference from MSDN, and in this form it hides itself in a 4,081-page OOXML specification, racing through Ecma and then straight into ISO. Is this right? Should a rejected standard from 1998, be fast-tracked to ISO over a successful, widely implemented alternative like SVG?

Why should you care? It is all about reuse.

If a standard reuses an already successful standard, it reuses the collective community wisdom that went into making that standard. It also reuses the considerable editorial effort in writing, editing and reviewing a technical specification. Reusing this effort lets the TC focus their time on on truly innovative aspects of their specification, and leads to a higher quality standard.
When you reuse a standard, you allow implementors to reuse the experience and knowledge they have already developed around that standard. Remember the 19 books dedicated to SVG? There is a lot of SVG knowledge out there. Why waste it?
Reusing an existing standard, especially a popular one like SVG, allows implementors to reuse the various code bases, both commercial and open source that support it. Why reinvent the wheel? Do you really want to rewrite a vector graphics engine? SVG has several good open source libraries including Apache Batik and librsvg.

Use SVG and you get reuse on three fronts. Stick with VML and the only thing that is reused is Microsoft’s legacy code. Using SVG is clearly the better choice.

I suggest that Ecma TC45 investigate this issue and consider moving off of VML and move to SVG, or at least demonstrate why it is impossible to do so. Why does the world need yet another XML vector graphics standard? If there is something missing in SVG (which I doubt) then why not work with the W3C to propose a enhancement for SVG rather than re-proposing the VML standard which was rejected back in 1998?

Again, I make no technical argument why SVG is or isn’t superior to VML. I merely note that SVG has been an adopted W3C standard for 5 years now and should have a presumption of suitability for the task, especially over a specification which were rejected 8 years ago.