These are the first generation of disc drives from Vortex. The interface supports either a single ("S" variant) or two ("D" variant) 80-track drives (BASF 6138). Additionally, a 3" [[Amstrad Disk Drive|FD-1]] can be connected as third drive, ie. unlike most other CPC disk interfaces it supports more than 2 drives. With [[VDOS]] only two drives are accessible at one time.
These drives interface interfacing with their own FDC can be used with the CPC 6128 to use different I/O ports (see below). TO BE CONFIRMED: Does the interface fully decode US0/US1 from NEC765 and if you select unit 3 which drive is accessed.
==== Variants ====