The 11/785 had access to an RX02 drive that was attachted to it pdp 11 console computer. The 11/780 and 11/782 probably were similar to that. The sysgen command connect console created csa0 and csa1 (IIRC) for use by VMS. Other VAX models with standard default floppies used 5.25” and 3.5” types.