Interesting. Say more. I am a confessed greybeard mainframe bigot, and I understand that the world has passed me by... so looking for education on that 'architecture eclipsed' bit. If you mean market and/or mind share; obviously... but this phrasing implies technical obsolescence. So are you referring to the insane amount of redundancy/resilience built into mainframes? I work for a large company with tens of thousands of x86 and proprietary (AIX, Solaris) servers of every stripe imaginable; converged and plain, virtualized and not. Every morning on our operations call there are alway a handful that have had some failure of some ilk. Sometimes they fall over to their secondary, sometimes not. In my 8 years here, we have had exactly ONE hardware failure in our 30k+ MIPS mainframe collection, and the internal redudancy of the box allowed the workload to continue un-interrupted for a week while we analyzed the failure and scheduled a fix. Turned out to be a microcode issue. So is THAT the eclipsed architecture, or do I need to go into I/O capabilities?