Just because I don't think I've mentioned it specifically yet: it will not be possible for Hammer to serve as a bootable volume in the 2.0 release.  2.2, definitely.
I've been traveling for a few days, so it's time you break out the bullet points again in an effort to catch up. Matthew Dillon posted a Hammer summary and warning on the 25th, along with another update today, mostly about mirroring and very large (terabyte!) files. Michael Neumann is also adding to Hammer functionality. He also did some initial porting work on netgraph from FreeBSD, though there's some objections. The purpose is to make updating certain utilites easier. This minor update to ATA support leads to a page with some interesting details about how ATA works. FreeBSDNews.net has set up a Google calendar for FreeBSD events, though I daresay many of the events will have multiple BSDs represented. You know how I always post about roguelike games here? The ultimate form of the roguelike has been announced. Dru Lavigne says "Grs!".  A bonus point to whomever figures out that reference...
Matthew Dillon's posted another Hammer update, this one looking forward to pseudo file systems and mirroring, and perhaps a bit farther.
Here's some BSD and Linux comparisons that happened to come up recently: First, NetBSD is moving to a 2-clause BSD license. Hubert Feyrer has mention of this, along with a small graph contrasting the word count of the GPL vs. the BSD license used in NetBSD, over time. KernelTrap has a post up about a position statement from the Linux Foundation that "urge[s] vendors to adopt a policy of supporting their customers on Linux with open-source kernel code." Compare that to the OpenBSD position on binary blobs.
The @Play column at GameSetWatch has another article on roguelikes. This covers early roguelike software that has become lost; a strange concept in today's world where everything is saved somewhere out there on the Internet. For an added bonus, the column has a link to a newspost from Moria's original author, which includes this interesting quote:
I plan to download it and Angband and play them... Maybe something has been added that will surprise me! That would be nice... I never got to play Moria and be surprised...
Is that perhaps the worst part of game development? You always know how the story ends.
More conversations about Hammer capabilites has been going on, on the kernel@ mailing lists, including where Matthew Dillon describes where Hammer's mirroring concept came from, and the possibilities of growing and shrinking filesystems. (Read to the end.) Also, he's put up a preliminary paper describing Hammer - what it does, how to use it, and future plans. There's a section on porting for those who might be interested. KernelTrap's still tracking progress, too. (Apparently Hammer does not need to be in all caps as I've been writing it, going by the paper.)
Matthew Dillon's latest HAMMER update warns of the usual need for a newfs, but says that the last change requiring this will go in today. Performance is on a par with UFS; this would be interesting for someone to benchmark and graph...
KernelTrap has a summary up of recent HAMMER development, though if you've been reading here, it'll already be familiar in a more truncated format. Also! There's a June 13th HAMMER update From Matthew Dillon, just to continue the trend.  Recompile and re-newfs, as usual. Following some of the article tags at KernelTrap creates an interesting topic-specific DragonFly history, incidentally.