What brand of computer was installed at Sterling Cooper Draper Pryce?

The computer installed at Sterling Cooper Draper Pryce was an IBM System/360. Its arrival is central to the Season 7 episode “The Monolith,” when the agency makes room for a large, climate-controlled mainframe and confronts the changing nature of office work.

IBM announced the System/360 family on April 7, 1964, and delivered systems from 1965 onward. Rather than being one machine, it was a compatible range of computers designed to handle both commercial and scientific workloads. Customers could move to more powerful models without completely replacing their software and peripherals, a major advantage at the time.

The machine was enormous by modern standards and required specialized operators, facilities, and maintenance. In Mad Men, its installation symbolizes the pressure automation places on traditional advertising jobs, especially copywriting and clerical work. The computer is not a personal desktop like the later Apple II, nor a small office machine such as the Commodore PET. Those alternatives belong to a later era and do not fit the agency’s late-1960s setting.