The large central computers of the 1950s to 1970s, which filled rooms and were shared by many users. The first computer artists worked on mainframes at universities, labs and companies.
He would then feed the cards into a mainframe computer, where a program modified the data and put it onto continuous paper tape, which the plotter required.
Caroline Csuri, Caroline Csuri on Charles Csuri and Computation as Playground
In the ‘60s, artists like Manfred Mohr would have used punch cards—writing in Fortran or something similar—and feeding them into a massive mainframe computer. The computer job would take hours or even days.
Matt DesLauriers, Matt DesLauriers on a Generative World