Every new system wants to be a mainframe when it grows up. VMS, Unix, Linux, NT...they all started "small" and gradually added the capabilities and approaches of the Bigger Iron that came before them.
Call that the mainframe--though it too has been evolving all along and is a much more moving target than the caricatures suggest. Clustering, partitions, cryptographic offload, new Web and Linux and data analytics execution environments, most recently data streaming and AI--many new use modes have been added since the 60s and 70s inception.
> Every new system wants to be a mainframe when it grows up. VMS, Unix, Linux, NT...they all started "small" and gradually added the capabilities and approaches of the Bigger Iron that came before them
True. Every new system wants to be just about everything when it grows up. Run workstations, process transactions, power factors, drive IoT, analyze data, run AI...
"Down" however is historically a harder direction for a design center to move. Easier to add features--even very large, systemic features like SMP, clustering, and channelized I/O--than to excise, condense, remove, and optimize. Linux and iOS have been more successful than most at "run smaller, run lighter, fit into a smaller shell." Then again, they also have very specific targets and billions of dollars of investment in doing so, not just hopeful aspirations and side-gigs.
Call that the mainframe--though it too has been evolving all along and is a much more moving target than the caricatures suggest. Clustering, partitions, cryptographic offload, new Web and Linux and data analytics execution environments, most recently data streaming and AI--many new use modes have been added since the 60s and 70s inception.