I'll make no secret of it: the BSDs really aren't my area of expertise. I've always seen them as the more ideologically developed alternative to Linux, which tends to take a more practical approach to development. Considering my lack of knowledge, here's what the team itself considers the most important new features and changes in FreeBSD 9.0.
- A new installer, bsdinstall(8) has been added and is the installer used by the ISO images provided as part of this release
- The Fast Filesystem now supports softupdates journaling
- ZFS updated to version 28
- Updated ATA/SATA drivers support AHCI, moved into updated CAM framework
- Highly Available Storage (HAST) framework
- Kernel support for Capsicum Capability Mode, an experimental set of features for sandboxing support
- User-level DTrace
- The TCP/IP stack now supports pluggable congestion control framework and five congestion control algorithm implementations available
- NFS subsystem updated, new implementation supports NFSv4 in addition to NFSv3 and NFSv2
- High Performance SSH (HPN-SSH)
- Flattened device tree (FDT), simplifying FreeBSD configuration for embedded platforms
- The powerpc architecture now supports Sony Playstation 3
- The LLVM compiler infrastructure and clang have been imported
- Gnome version 2.32.1, KDE version 4.7.3
As always, architecture support is outstanding, so no matter if you have an amd64, i386, ia64, powerpc, powerpc64, or sparc64 box, FreeBSD 9.0 will happily run. One note, though - a problem was found with the DVD images for amd64 and i386; new images have since been uploaded, but if you downloaded one of these images before this announcement, it's wise to re-download the image, or verify its checksum.
Have fun, and FreeBSD users, let us know how it goes!