Re: Alternatives?
Sun had very little interest in Linux on larger systems, at least until it could be run in a virtualised environment. They wanted to sell Solaris, and made sure that customers bought Solaris by- in part- making sure that it was the only way to get things like environmental monitoring; this is, of course, exactly what IBM does on its bigger iron.
Oracle seem to have little interest in their own Linux targeting SPARC. From their POV, the desktop is x86 and the backend is Solaris.
OpenSolaris (or whatever it's called these days) is available for SPARC in the form of OpenSXCE. Unfortunately the developer of this has strong political opinions, which results in his website being hacked to oblivion on a regular basis. A great pity, since he's done some good work.
As far as "real computers" go, i.e. things that can hold lots of discs, lots of Gb RAM, and lots of CPUs, there's no real alternative to x86 and x86-64. Itanium's dead and was dropped by Debian a year or so ago, MIPS is good for small stuff but it's unclear whether China really does have the balls to push it, and ARM has never really penetrated that part of the industry.