> Mainframes were meant, yes?
No not at all. We’re talking early-mid 1980s so people in the research community (at least at the leading institutions) were by then pretty used to what’s called cloud computing these days. In fact the term “cloud” for independent resources you could call upon without knowing the underlying architecture came from the original Internet papers (talking originally about routing, and then the DNS) in the late 70s
So for example the mail or file or other services at PARC just lived in the network; you did the equivalent of an anycast to check your mail or look for a file. These had standardized APIs so it didn’t matter if you were running Smalltalk, Interlisp-D, or Cedar/Mesa you just had a local window into a general computing space, just as you do today.
Most was on the LAN, of course, as the ARPANET was pretty slow. But when we switched to TCP/IP the LAN/WAN boundaries became transparent and instead of manually bouncing through different machines I could casually check my mail at MIT from my desk at PARC.
Lispms were slightly less flexible in this regard back then, but then again Ethernet started at PARC. But even in the late 70s it wasn’t weird to have part of your computation run on a remote machine you weren’t logged into interactively.
The Unix guys at Berkeley eventually caught up with this (just look at the original sockets interface, very un-unixy) but they didn’t quite get it: I always laughed when I saw a sun machine running sendmail rather than trusting the network to do the right thing on its behalf. By the time Sun was founded that felt paleolithic to me.
Because I didn’t start computing until the late 70s I pretty much missed the whole removable media thing and was pretty much always network connected.