The Durango F85 was an early Personal computer introduced in 1977 by Durango Systems Corporation. It could run its own multitasking operating system called DX-85M, which included an integral Indexed Sequential (ISAM) file system and per-task file locking, or alternatively CP/MDurango later dropped the "F-85" model name and adopted a user model system, with 700 being the entry model and 950 being the full-featured model, and still later designed a 16-bit system, The Durango "Poppy".