[andrewl]

It may be experimental in that it's diverged significantly from FreeBSD, from which it was forked. But experimental does not mean new. Release 1.0 was in July 2004. Apparently the lead developer's experience with the Amiga OS influenced the project to some degree.

[loeg]

Yeah, Dillon (lead developer) forked FreeBSD 4 over (at least) a dispute in how SMP should be implemented. (FreeBSD 5 was the first release to support SMP.) DragonFlyBSD => DFBSD => Dillon's FreeBSD.

[jabl]

I recall back then Dillon had some unconventional ideas how to do SMP compared to the traditional approach of ever more fine-grained locking as done by FreeBSD and Linux. Is DragonFlyBSD still following this design, and if so, how well did it work out, or if not, did they revert to a more traditional approach?

[loeg]

I don't follow DFBSD development too closely, but it looks like they still have the somewhat novel lock tokens:

https://www.dragonflybsd.org/docs/developer/Locking_and_Sync...

I don't know how well it works for them or if they've gone back to using more typical locking more recently.

[tedunangst]

FreeBSD 3 supported SMP. FreeBSD 5 had the "new" SMP.

[loeg]

Mea culpa. This all predates my involvement.