"Sun has made good on its promise to deliver OpenSolaris, the
company's Unix-based answer to Linux, with a company-supported,
commercial update arriving in mid-May. Although far from a complete
product, the latest OpenSolaris is impressive and in the long run
could prove a viable alternative to Linux.
"Part of OpenSolaris' appeal is that it contains a subset of the
source code for the Solaris Operating System, but with an open
source license. Among the familiar Sun features are the enviable
DTrace tuning and monitoring tool and the ever-impressive ZFS
filesystem, neither of which are likely to make it to Linux due to
licensing and personality conflicts.
"On the other hand, larger Linux efforts like Debian (which is
the basis of Ubuntu) have an impressive range of open source
software packages which, so far, OpenSolaris can't match..."