Thursday, September 07, 2006

Guardian: "Dave Winer's 'river of news' finally looks like catching on." 

On this day in 2004, a drive from Kelowna to Seattle. 

Valleywag says John Doerr's departure from the Sun board signals a looming Sun sell-off. 

Jason Pontin reads Scripting News.  

Om Malik: "Treo has issues." 

Chris Heuer: "I was not saying anything about the O'Reilly situation in the hopes I might be able to one day talk to him about what's going on." 

Fred Wilson explains the change at Facebook that's sparking a revolt by users. "Social networks to date have been these big unmanageable messes. Facebook is addressing that by giving users a tool to consolidate the information they care about." 

The RSS "ttl" element and P2P networks 

There's been some recent discussion of the RSS 2.0 ttl element. There's a bit of history to it, and a grand plan that as far as I know, was never put into action.

The initial discussion of the element was on 5/19/02, as part of document proposing three new elements: pubDate, guid and ttl. It was linked to from Scripting News on that day.

In April and May of 2002, we were working with Streamcast Networks, the makers of the Morpheus P2P client on integrating RSS with Gnutella. The ttl element was the key that would allow the network, which consisted of many millions of nodes, to share RSS feeds that were hosted on servers that likely couldn't take the pounding such a network could deliver. At the time, Morpheus was trying to re-launch after being shut down by a court order. I learned a lot from their CTO, Darrell Smith, who I spoke with several times, at length, in the spring of 2002.

Here's how ttl was intended to work. Suppose you have a copy of Gnutella running on your machine, and I have one running on my machine. My machine wants a copy of a certain feed, so it asks your machine if it has it. Your copy of Gnutella looks in its cache, finds a copy of the feed, takes the lastBuildDate, adds its ttl value. If the resulting time is greater than the current time, it says yes, I can give you that, otherwise it says no. If your Gnutella strikes out, if everyone it asks says no, it reads the feed from the feed's server.

I'm not sure what happened at Morpheus, but this was just before I got knocked out in June, and I didn't return to UserLand after that, so the project with Streamcast was never completed. The ttl element, however, made it into the RSS 2.0 spec, later that year, and it's still there, presumably ready to be used should this problem ever appear. Of course, in practice, in 2006, there aren't many feeds that receive so many hits as to require this peer-to-peer treatment. The market went a different way, at least for now.

Hope this helps.

Roasted hot green peas 

Super yummy!