The Rise of the Rolling Release
Rolling releases are not new. Gentoo was one of the first, if not the actual, that was considered a rolling release. Later rPath, then PCLOS came along and Sabayon followed. Arch joined the fray and openSUSE began Tumbleweed. But more projects are kicking around the idea these days and some have even done it.
Rolling release are those systems which are updated in smaller increments over time usually from within the system with a software management client as opposed to the more traditional installation of a new system every so often. The advantages to the user is obvious, but the developer has his reasons as well. That's why more and more projects are implementing the rolling release model, or are at least talking about it. Here are two very recent examples.
Ubuntu Rolling Release
It's been making big news and spawned several passionate blog posts. It's been rumored before, but it's now being scheduled for discussion at the next Ubuntu Developer Summit. That's right, an Ubuntu rolling release. Lead Ubuntu developers are saying the rolling release model would probably fit in better with the future that Ubuntu looks to be heading. Of course there are those that are all for it, and some who are not because rolling release can and do break (at the most inconvenient times). But it's just an intriguing idea for now. OMG!Ubuntu! has more details on that.
PC-BSD 9.1 Rolling Release
FreeBSD News reported last week that the PC-BSD project has uploaded the first test images for their rolling release branch and that the news was "well received" by the community. An online updater is being polished for those starting with a standard release.
But Not Fedora
Fedora rolling releases were the subject of many discussions recently as well. In fact, it keeps coming up, but many commonly point to Rawhide. Rawhide is the developmental branch of Fedora that can be used as a basis for an operating system. It's risky, and while some folks like it, Rawhide isn't a rolling release. Rumors and discussions will probably persist.