Interesting, how are you getting up to 2048 CPU, is it virtual? The largest SSI I've heard about are 1024, and that wasn't long ago. This probably isn't just straight "Linux" either is it, don't you need some proprietary SSI software from IBM or SGI, etc to provide the boot layer? I've heard about OpenSSI but it's nowhere close to this is it? You're right about the programming advantages though, I've heard programming for the clusters can be difficult, and why so many stick with their old Cray or IBM Mainframe.