Solaris 10 Released
AusG4 writes "Sun Microsystems has released Solaris 10 for both SPARC and Intel/Opteron. Downloading it is the usual 'register and get your free license' meandering; the Intel/Opteron version is 4 CDs and an optional language and companion disc (a bunch of pre-compiled GNU software in pkgadd format, I'm assuming, same as Solaris 8 and 9)."
Solaris is no longer available for "SPARC" systems, only UltraSPARC systems. It no longer supports sun4m or sun4d.
Solaris 10 zones have much better performance than UML, more comparable to Xen or FreeBSD jails. However, Xen runs only on IA32, where Solaris also does AM64 and Sparc. Xen and UML also don't support multiprocessor machines, if I'm not mistaken, and FreeBSD jails do not support things like resource managers, in case of a jail process bringing the whole machine (and other jails) down. Sun has its Fair Share Scheduler, where you can bind a container to one or more processors.