That was the 1960s-80s way of working with computers. Multiple terminals connected to a single timesharing mainframe (or mini, for that matter). You might have a network like DECNET, but mostly it would be hardwired terminals, or if you were less lucky, a dialup modem and an acoustic coupler at a blazing 300 bps. You were sharing one machine with potentially dozens of other developers.

Legacies of this abound in Linux (even the ability to SSH in is a descendant of this world). Commands like "who" are there to show who's logged in, and there's even an entire process accounting system that can be switched on to bill your users for CPU time.