They're not even really new or untested, just being done at a different plane of abstraction. Running a system efficiently across multiple machines requires dif

They're not even really new or untested, just being done at a different plane of abstraction. Running a system efficiently across multiple machines requires different implementations of familiar abstractions than running on a single machine. Even the single machine approach has changed dramatically in the last 20+ years. We started single program, went to single user, to multi-user, to multi-processor, to multi-core, to NUMA, etc (not necessarily in that order), and a significant subset of systems are now multi-machine, even if you ignore the internet. All of these new paradigms tend to have similar base requirements/optimizations that would kind of be pointless to reinvent versus simply adapting to the new infrastructure style.