In general, the new systems assign dedicated disk drives to each processor (shared-nothing) while the older systems apply multiple processors to a shared storage pool. Each approach has its strengths and weaknesses, which introduce new differences to consider. In addition, the broader adoption of multiple processors and 64-bit memory removes some of the performance constraints that impacted earlier systems. First I’ll revisit the original list of items to see which are still relevant, and then I’ll add a few new ones.