Metalink takes off!

In a world of unintended consequences, one I often think about is not realizing how many new friends I would make because of my kids. Through numerous events, car-pooling, baby sitting, play dates, parties, and years of schooling with the same kids in their classes, I gained a whole new set of good friends (the parents that is, not the kids!).

Similarly, I hadn't realized when starting my blog that you can make some very interesting connections and virtually meet people who share your interests. It's a great benefit, and here's a great example. Soon after starting my blog, I "met" Anthony Bryan via some thoughtful, intelligent comments he left on subjects I was discussing. He must've found me due to my interest in ESD and download managers -- if you look around, there's simply not that much written about those subjects. And it's always great to find others who share your interests and passions.

I first mentioned Anthony's project, Metalink, almost two years ago, when he was just starting to gain traction. We've kept in touch, and it's really amazing to see how it's taken off since then. It's no accident of course -- it took perseverance, in combination with his clever, well-implemented, open technology. Metalink filled a gap in download managers and systems, providing for much needed enhanced redundancy, load sharing, and fault tolerance for large file downloads.

There's a long list of products now that incorporate Metalink, a sure sign of growing acceptance and success. I was going to mention a few, but I see his home page is up-to-date and says it much better than I can, so take a look. Also, here's an informative interview with Anthony about his project and its benefits.

So, what about Sun Download Manager (SDM), does it use Metalink? Well, no, not yet at least. The main reason is that SDM's primary audience is customers downloading Sun software from Sun Download Center (SDLC). Access to this software is carefully controlled for security and export control reasons. We use load management to distribute the load on multiple servers in our own data centers. As there aren't mirrors our there for this class of software (i.e., mostly not Sun's open source software), we lose one of the main advantages of Metalink. That said, we do know a lot of people use SDM on other sites because it's a good, simple, free, cross-platform download manager. So that sounds like a good argument to build in Metalink support in the future! (I'll say it before Anthony does.) I'll certainly keep it on the radar, but must admit all our engineers are tied up finishing our new download system at the moment.

In the meantime, I see that Metalink is used for OpenOffice distribution and was further pleased to see it mentioned in a number of other Sun blogs

Congratulations Anthony, and I hope Metalink is just the first of many successes for you. 


I am happy to see such a good progress with the new download system and the will to evaluate Metalink support for it!

You can find working PHP and Python example code in the Metalink Library:

Some of the features are automatic parsing of Torrents, mirror, hash and local download files.

If you have any questions or feature requests, please let me know, add a Wiki comment or file an entry to the Issue Tracker.

Keep up the good work,

Posted by René Leonhardt on November 29, 2007 at 04:12 PM PST #

Hi René, thanks much for your comments and links to the metalink resources. I see you've worked on the project in producing these libraries and appreciate your efforts!

Posted by Gary Zellerbach on November 30, 2007 at 01:50 AM PST #

Gary, thank you very much for posting about Metalink, and for the dialogue.

Us download aficionados are few & we need to stick together. :)

I would of course be ecstatic if SDM was going to use Metalink, and it would also be interesting to eventually see (experimental?) .metalinks for downloads as Metalink gets incorporated into browsers and other download managers.

Happy holidays to you & your family!

Posted by Anthony Bryan on December 26, 2007 at 05:20 AM PST #

Hello Gary,

It's not easy today to get the JDK download page displayed... ;)

By the way, the Metalink Library has a simple and effective command-line interface since version 1.1.
In addition, BitTorrent files can now easily be imported or generated.

# Create .metalink and .torrent files for every found file > 1 MB jdk-\* --create-torrent=

Posted by René Leonhardt on January 08, 2008 at 03:38 PM PST #

Hi Rene,

Thanks for the update on the Metalink Library -- you are doing some excellent work! Regarding your comment on the JDK download page, I'd be happy to pass along any feedback to the team that manages it, if you wish to elaborate a bit.

Posted by Gary Zellerbach on January 10, 2008 at 01:50 AM PST #

Hi Gary,

I am just using a website watcher to keep me up-to date with all the latest software versions and I recognized the availability of Java 6 Update 4, but both download links (JDK 6u4 and JRE 6u4) kept on resulting in timeouts.
After a while they replaced the download links by the last version (6u3) and I just got the new JRE from a mirror site, which provided an authenticated link, but unfortunately not for the JDK.

I hope some of the distribution folks will look into Metalink and BitTorrent to help avoiding such problems in the future.

Thank you, the next version will probably introduce a Ruby port of the library in addition to PHP and Python.

Posted by René Leonhardt on January 10, 2008 at 03:13 AM PST #

Hi Rene,

Thanks for getting back to me with more info. My understanding is that the JDK for 6u4 is coming out very soon (it may even be live by the time your read this, but I'm not directly involved in the release). Sounds like maybe the staging links got accidentally exposed prematurely, then got reverted back to the prior release until the "official" release happens on Stuff happens! Sorry for any inconvenience. I'd suggest giving it another try shortly.

I do know that 6u4 will be the first JDK release on our new download system. These releases get a LOT of traffic, so it should be a good test!


Posted by Gary Zellerbach on January 10, 2008 at 07:23 AM PST #

Hello Gary,

Java 6u4 seems to be available from now on, the JDK download went very smoothly (I did not try the Sun Download Manager, though).

The Windows i586 version is 4 MB bigger than 6u3, but wow, 376 bug fixes, good job!

Posted by René Leonhardt on January 11, 2008 at 07:33 AM PST #

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I helped design, build, and manage download systems at Sun for many years. Recently I've focused on web eMarketing systems. Occasionally, I write about other interests, such as holography and jazz guitar. Follow me on Twitter:


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