Mission to Mars
Adobe published a prerelease version of Mars on Adobe Labs last week, and blog posts are starting to show up. I’m very happy with the response so far – most everyone who looks at it has good things to say about it. However, one of the more common memes around the Mars release is that it is nothing more than a ‘me-too’ response to XPS. That isn’t the case: Mars has been in the works since before XPS was even a twinkle in Microsoft’s eye.
The origins of Mars began way back in 1999 when Jim King and Chip Brown experimented with a PDF representation that used ZIP-based packaging of SVG page content built on Acrobat 4.0. At the time, it was known internally as PDML (for Page Description Markup Language) and later became known as XDF (XML Document Format, I presume).
In 2003, Phil Levy began work on a new implementation of the idea, with the intention of productizing the technology as part of Acrobat 7.0. Unfortunately, the feature didn’t make it in time for Acrobat 7.0, but it was present in at least one public Acrobat 7 beta release. In retrospect, getting cut from Acrobat 7 was a good thing, as the feature wasn’t quite ready for the Acrobat 8.0 release in November 2006 either 🙂 Seriously, though, the design did get refined quite a bit over the last year and a half. The early version of Mars used an Adobe-defined packaging mechanism, while the current version uses the packaging mechanism defined in the OEBPS Container Format, which in turn is built on top of ODF. The early version supported only a subset of PDF, while the current version supports virtually all PDF features with only a few legacy edge cases unsupported. Maintaining backward compatibility with PDF was a critical feature for Mars.
Bottom line on all this history, though, is that the Mars technology has a long history here at Adobe and is not something we just threw together as a response to Microsoft. It is, in fact, a much richer and more standards-based technology than anything Microsoft is attempting. Eliot Kimber said it better than I ever could:
After seeing Adobe’s presentation and talking to the guys from Adobe it’s clear that what they’ve done is a sincere and well-thought-out attempt to Do The Right Thing rather than a cynical recasting of proprietary stuff into markup so it’s “open.”
MARS tries to use standards as much as it can and it seems to do so to a remarkable level of completeness. It uses SVG for representing each page, supports the usual standards for media objects (bitmaps, videos, etc.). Uses Zip for packaging, and so on.
I’ll talk more about why Mars and standards in a future blog post.
Shebanator 
I think this is really good news. Just my own opinion but would it not have been worth considering to concentrate more on this for Acrobat 8 than the Breeze add ons that may or may or may not be interesting for people who have followed PDF over the years?
My impression is that the Acrobat Users site is not yet covering Mars to any great extent. Will this change?
I am asking about this as there was an Acrobat User Forum in the UK that now meets very infrequently. XML was definitely a topic, like the cost of server software.
So this Mars project is interesting.
Nothing against Flash of course.
I guess I simply do not get what problem Microsoft’s XPS file format is trying to solve. I hear that they are going to submit XPS to ‘standards organizations” – which one(s)? WHich one cares ?
Michael,
That is IMHO an excellent question, but that is one you’d be better off asking Microsoft. My snide side says the problem is that Microsoft doesn’t own or control PDF.