Different era - I was using the Elliott in 1967/68
Same again - the 1903S was released in 1971 and was a medium scale machine - and ours was a fairly small example.
memory
Sure, but you couldn't physically fit that much RAM into an IBM PC-AT or PC-XT
Around 1980 I was working at the BBC, this time on ICL 2966 systems. The production system was normally running 11 or 12 different online systems that together supported around 400 green-screen 24x80 terminals. This mainframe had 16MB of RAM. The development system also served as backup for the live system and had even less RAM - 8MB - I never knew how many developers it supported, but we were all using it interactively, writing interactive systems in COBOL the used IDMSX databases.
Not that any of the above is relevant to my point - which is that before multi-colour graphical displays became the norm, personal computers and mainframes running typical back-office systems could and did routinely use what now look like laughably small amounts of memory.