OS Review: NetBSD 1.6.2 on SPARC64
JigSaw writes "NetBSD is the king of operating system portability, running on 40+ different hardware platforms, including x86, MIPS, and even the Sega Dreamcast. So it comes as no surprise that among the supported platforms, NetBSD runs on Tony Bourke's Sun Ultra 5. Here is his review."
a 64-bit kernel with 32-bit userland.
NetBSD wants to have 64-bit userland.
That said, I don't think there's anything major that can't be fixed. Once installed, it's run flawlessly, and the only package I couldn't compile from pkgsrc is Apache 2.x (I installed Apache 1.x instead).
I've had the (32-bit) sparc port of NetBSD running solidly on a SparcStation-2 for over a year and a half (it's my DHCP/NTP/DNS server).